Download - SimXpert R3.2 Crash Workspace Guide
1Introduction
Crash Workspace GuideIntroduction
Overview and Definition2
Overview and DefinitionAn overview of the SimXpert crash workspace is given here.
IntroductionSimXpert crash is a preprocessor for graphically preparing input data for LS-DYNA, an explicit dynamic software, used in applications such as crash, crush, and drop test simulations. Use of crash workspace allows users to work within one common modeling environment with other SimXpert workspaces such as Structures. Thus, for example, a model originally prepared for NVH, linear, or implicit nonlinear analysis can be easily used in explicit applications (crash). This dramatically reduces the time spent to build different models for implicit and explicit analysis and prevents you from making mistakes because of unfamiliarity between different programs.
TheoryA detailed theory of explicit analysis is outside the scope of this guide. However, it is important to understand the basics of the solution technique, since it is critical to many aspects of using the SimXpert crash workspace. If you are already familiar with explicit methods and how they differ from implicit methods, you may disregard this section.
Method of SolutionAlthough crash simulation software, including LS-DYNA uses the Explicit methods, a brief overview of both the Implicit and the Explicit Methods for the solution of dynamic response calculations is given below.
Implicit Methods
Most finite element programs use implicit methods to carry out a transient solution. Normally, they use
Newmark schemes to integrate in time. If the current time step is step , a good estimate of the
acceleration at the end of step will satisfy the following equation of motion:
where:
= mass matrix of the structure
= damping matrix of the structure
= stiffness matrix of the structure
= vector of externally applied loads at step
n
n 1+
Ma'n 1+ Cv'n 1+ Kd'n 1++ + Fn 1+ext
=
MCKFn 1+
extn 1+
3IntroductionOverview and Definition
and the prime denotes an estimated value.
The estimates of displacement and velocity are given by:
or
where is the time step, and , and are constants.
The terms and are predictive and are based on values already calculated.
Substituting these values in the equation of motion results in
or
The equation of motion may then be defined as
The accelerations are obtained by inverting the matrix as follows:
This is analogous to decomposing the stiffness matrix in a linear static analysis. However, in dynamics, mass and damping terms are also present.
= estimate of acceleration at step
= estimate of velocity at step
= estimate of displacement at step
a'n 1+ n 1+v'n 1+ n 1+d'n 1+ n 1+
d'n 1+ dn vnΔt 1 2β–( )anΔt2( ) 2 βa'n 1++⁄ Δt
2+ +=
v'n 1+ vn 1 γ–( )anΔt γa'n 1+ Δt+ +=
d'n 1+ dn* βa'n 1+ Δt
2+=
v'n 1+ vn* γa'n 1+ Δt+=
Δt β γ
dn* vn
*
Ma'n 1+ C v*n γa'n 1+ Δt+( ) K d*n βa'n 1+ Δt2
+( )+ + Fn 1+ext
=
M CγΔt KβΔt2
+ +[ ]a'n 1+ Fn 1+ext
Cvn*– Kdn
*–=
M*a'n 1+ Fn 1+residual
=
M*
a'n 1+ M*1–Fn 1+
residual=
Overview and Definition4
Explicit Methods
The equation of motion
can be rewritten as
where:
The acceleration can be found by inverting the mass matrix and multiplying it by the residual load vector.
In LS_DYNA, like any explicit finite element code, the mass matrix is lumped which results in a diagonal mass matrix.
Since is diagonal, its inversion is trivial, and the matrix equation is a set of independent equations for each degree of freedom, as follows:
The Leap-frog scheme is used to advance in time.
The position, forces, and accelerations are defined at time level , while the velocities are defined at time
level . Graphically, this can be depicted as:
= vector of externally applied loads
= vector of internal loads (e.g., forces generated by the elements and hourglass forces)
=
= mass matrix
Man Cvn Kdn+ + Fnext
=
Man Fnext
Fnint
–=
an M1–Fn
residual=
Fnext
Fnint
Cvn Kdn+M
M
ani Fniresidual
Mi⁄=
n
n 1 2⁄+
vn 1 2⁄+ vn 1 2⁄– an Δtn 1 2⁄+ Δtn 1 2⁄–+( ) 2⁄+=
dn 1+ dn vn 1 2⁄+ Δtn 1 2⁄++=
5IntroductionOverview and Definition
The Leap-frog scheme results in a central difference approximation for the acceleration, and is second-
order accurate in .
Explicit methods with a lumped mass matrix do not require matrix decompositions or matrix solutions. Instead, the loop is carried out for each time step as shown in the following diagram:
Explicit Time Step
Implicit methods can be made unconditionally stable regardless of the size of the time step. However, for explicit codes to remain stable, the time step must subdivide the shortest natural period in the mesh. This means that the time step must be less than the time taken for a stress wave to cross the smallest element in the mesh. Typically, explicit time steps are 100 to 1000 times smaller than those used with implicit codes. However, since each iteration does not involve the costly formulation and decomposition of matrices, explicit techniques are very competitive with implicit methods.
Because the smallest element in an explicit solution determines the time step, it is extremely important to avoid very small elements in the mesh.
n 1– n 1 2§– n n 1 2§+ n 1+ time
d F a, , d F a, , d F a, ,v v
Δt
Grid-Point Accelerations
Grid-Point Velocities Grid-Point Displacements
Element Stain Rates
Element Stresses
Element Forces at Grid-Points
+ External Forces at Grid Points
Leap-frog Integration in Time
Element Formulation and Gradient Operator
Constitutive Model and Integration
CONTACT, Fluid-Structure Interaction, Force/Pressure boundaries
Element Formulation and Divergence Operator
Overview and Definition6
Courant Criterion
Since it is impossible to do a complete eigenvalue analysis every cycle to calculate the timestep, an approximate method, known as the Courant Criterion, is used. This is based on the minimum time which is required for a stress wave to cross each element:
where:
For 1-D elements, the speed of sound is defined as:
where:
Implicit vs. Explicit Analysis
The time step for implicit solutions can be much larger than is possible for explicit solutions. This makes implicit methods more attractive for transient events that occur over a long time period and are dominated by low frequency structural dynamics. Explicit solutions are better for short, transient events where the effects of stress waves are important. There is, of course, an area where either method is equally advantageous and may be used.
Explicit solutions have a greater advantage over implicit solutions if the time step of the implicit solution has to be small for some reason. This may be necessary for problems that include:
• Material nonlinearity. A high degree of material nonlinearity may require a small time step for accuracy.
• Large geometric nonlinearity. Contact and friction algorithms can introduce potential instabilities, and a small time step may be needed for accuracy and stability.
• Those analyses where the physics of the problem demands a small time step (e.g. stress wave effects as in crash, crush, and impact analyses).
= Timestep
= Timestep scale factor (<1)
= Smallest element dimension
= Speed of sound in the element material
= Young’s modulus
= density
tΔ SL/c=
ΔtSLc
c E ρ⁄=
Eρ
7IntroductionOverview and Definition
• Material and geometric nonlinearity in combination with large displacements. Convergence in implicit methods becomes more difficult to achieve as the amount of nonlinearity for all types increases.
Explicit Methods Have Increasing Advantages Over Implicit Methods as the Model Gets Bigger and Bigger.
Overview and Definition8
9Parts and Geometry
Parts and Geometry
Parts and Geometry10
Parts and GeometryThe geometry of the parts can be either created in SimXpert, or more likely imported from CAD program such as Catia, Pro/E.
UnitsSimXpert interprets all dimensions and input data with respect to a system of units. It is important to set the appropriate units prior to importing any unitless analysis files (such as a Nastran Bulk Data file) or creating materials, properties, or loads. You can control the system of units by selecting Units Manager from the Tools menu. If you import a file that contains units, SimXpert will convert them into those specified in the Units Manager.
Creating GeometryIn the first release SimXpert has very limited geometry creation capabilities. It is possible to create curves and very simple surfaces. For the most part you will be importing geometry from an external source. The imported geometry can be edited in SimXpert
Importing GeometryIf the geometry of the part is available in a CATIA, parasolid, IGES, or STL file, it can be directly imported into the SimXpert Crash Workspace.
Creating local coordinate systemsSometimes it is convenient to use local coordinate systems for specifying loads, and or boundary conditions. For example, a certain node may have a roller support placed in an inclined plane. A local
11Parts and GeometryParts and Geometry
coordinate system with one of its axes normal to the inclined plane needs to be created and used to specify the fixity (SPC) of the displacement component along the direction normal to the inclined plane.
Local coordinate systems can be in cartesian, cylindrical or spherical systems. Coordinate system created in SimXpert are represented by the following icons, corresponding to the method selected.
You can create local coordinate systems by selecting Cartesian, Cylindrical, or Spherical from the Coordinate System group under the Geometry tab. There are numerous methods to create local coordinate systems in SimXpert:
Coordinate System
Direction 1
Direction 2
Direction 3 1-3 plane
Cartesian x y z x-z (y=0)
Cylindrical r z r-z ( =0)
Spherical r r- ( =0)
CONSTRAINTCONSTRAINT
Cartesian
Cylindrical
Spherical
θ θθ φ φ θ
Parts and Geometry12
1. 3 Points: Three points are used to define the coordinate system. The first point corresponds to the location of origin. The second point defines the point on a specified axis and the third point defines a point in a specified plane.
2. Euler: Creates a coordinate system through three specified rotations about the axes of an existing coordinate system.
3. Normal: Creates a coordinate system with its origin at a point location on a surface. A specified axis is normal to the surface.
4. Two Vectors: Creates a coordinate system with its origin at a designated location and two of the coordinate frame axes are defined using vectors
5. Advanced: Location and orientation can be independently defined. There are 4 different ways to define the location of the origin of the coordinate system: Geometry, Point/Node, Coordinate System, and Center of Part. Further, the orientation can also be defined 3 ways: Global, Two Axes, and Coordinate System.
13Materials
Materials
Materials14
MaterialsSimXpert Crash Workspace supports most of the LS-DYNA material types, covering isotropic, anisotropic, orthotropic, and laminated material properties. These material properties can be dependent on temperature, strain, and strain rate. Here we briefly describe all the material types supported currently by the crash workspace. Please refer to “LS-DYNA Keyword Users’ Manual”, for a full description of all the LS-DYNA supported materials.
Supported Materials
MAT_ADD_EROSION
This material model option provides a way of including failure in material models that do not allow failure and erosion. This option can also be applied to constitutive models with other failure and erosion criterion. Each of the criterion defined here is applied independently, and once any of them is satisfied, the element is deleted from further calculation.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0) for which this erosion definition applies.
EXCL The Exclusion number. When any of the failure constants are set to the exclusion number, the associated failure criteria calculations are bypassed. For example, to prevent a material from going into tension, you may specify an unusual value for the exclusion number, e.g. 1234., set Pmin to 0.0 and all the remaining constants to 1234. The default value is 0.0, which eliminates all criteria from consideration that have their constants set to 0.0, or left blank.
PFAIL Pressure at failure, Pmin. Failure occurs when pressure is less than PFAIL
15MaterialsMaterials
Remarks:1. This failure model only applies to the 2D and 3D solid elements with one point integration.
See Also:• LS-DYNA Keyword User’s Manual
MAT_ANISOTROPIC_ELASTIC
This material model is used for modeling elastic anisotropic behavior of solids.
SIGP1 principal stress at failure, σmax. Failure occurs when the maximum principal stress exceeds SIGP1.
SIGVM Equivalent stress at failure, σvM. Failure occurs when the von Mises equivalent stress exceeds SIGVM.
EPSP1 Principal strain at failure, εmax. Failure occurs when the maximum principal strain exceeds EPSP1.
EPSSH Shear strain at failure, γmax. Failure occurs when the maximum shear strain exceeds EPSSH.
SIGTH Threshold stress, σ0 (used in evaluating the Tuler-Butcher criterion)
IMPULSE Stress impulse for failure, Kf. Failure occurs when the Tuler-Butcher criterion exceeds IMPULSE.
FAILTM Failure time. When the analysis time exceeds the failure time, the material is removed.
Field Contents
Title Unique name identifying the material model.
Desc Optional description of the material model.
Field Comments
Materials16
See Also:• LS-DYNA Keyword User’s Manual
MAT_BLATZ-KO_RUBBER
This is used to model nearly incompressible continuum rubber. The Poisson’s ratio is fixed to 0.463
See Also:• LS-DYNA Keyword User’s Manual
TITLE_OPTION If selected, the material Title will be exported to LS-DYNA
MID Material identification number. (Integer > 0)
RO Mass density.
C11... C66 Anisotropic constitutive matrix components
AOPT Material axes option
XP, YP, ZP Coordinates for point P (for AOPT= 1 and 4)
A1, A2, A3 Components of a vector a (for AOPT=2)
D1, D2, D3 Components of a vector d (for AOPT=2)
V1, V2, V3 Components of a vector v (for AOPT= 3 and 4)
BETA Material angle in degrees (for AOPT= 3)
REF Use Reference geometry to initialize the stress tensor
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear modulus
REF Use reference geometry to initialize the stress tensor (0 =off; 1 = on)
Field Contents
17MaterialsMaterials
MAT_CABLE_DISCRETE_BEAM
This material model is used to define elastic cables realistically.
Remarks:1. The force, F generated by the cable is nonzero if the cable is in tension. The force is given by:
F = max (F0 + KΔL, 0.)
where K is the stiffness, and ΔL is the change in length. If E is greater than zero, K is defined as:
K = (E X cross sectional area)/ (Initial length - offset)
2. A constant force element can be obtained by setting:
F0 > 0, and K = 0
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass density
E Young’s modulus (if value greater than zero), or stiffness (if value smaller than zero)
LCID Load curve Id for loading (engineering stress vs. engineering strain)
F0 Initial Tensile Force
TMAXF0 Time for which pre-tension force will be held
TRAMP Ramp-up time for pre-tension force
IREAD Flag: If value greater than zero, use the value of OUTPUT from card 2.
OUTPUT Flag = 1 to output axial strain
Materials18
3. The cross section, and offset are defined on the *SECTION or *ELEMENT cards. For a slack cable, the offset should be input as a negative value. For an initial tensile force, the offset should be positive.
4. If a load curve is specified, the Young’s modulus will be ignored, and the load curve will be used instead. The points on the load curve are defined as engineering stress vs. engineering strain. The unloading behavior follows the loading.
See Also:• LS-DYNA Keyword User’s Manual
MAT_ELASTIC
This LS-DYNA material model (001) is an isotropic elastic material available for beam, shell and solid elements.
Remarks:1. The axial and bending damping factors are used to damp down numerical noise. The update of the
force resultants, , and moment resultants, , includes the damping factors:
Field Contents
Title Unique name identifying the material model.
Desc Optional description of the material model.
TITLE_OPTION If selected, the material Title will be exported to LS-DYNA
MID Material identification number. (Integer > 0)
RO Mass density.
E Young’s modulus
PR Poisson’s ratio
DA Axial damping factor (used in Belytscho-Schwer beam type 2 only)
DB Bending damping factor (used in Belytscho-Schwer beam type 2 only)
Fi Mi
19MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_ELASTIC_FLUID
This LS-DYNA material model (001) is an isotropic elastic material available for solid elements.
Field Contents
Title Unique name identifying the material model.
Desc Optional description of the material model.
TITLE_OPTION If selected, the material Title will be exported to LS-DYNA
MID Material identification number. (Integer > 0)
RO Mass density.
E Young’s modulus
PR Poisson’s ratio
DA Axial damping factor (used in Belytscho-Schwer beam type 2 only)
DB Bending damping factor (used in Belytscho-Schwer beam type 2 only)
K Bulk Modulus (for fluid option)
VC Tensor viscosity coefficient (between 0.1 and 0.5)
CP Cavitation pressure (default = 1.0E+20)
Fin 1+
Fin
= 1DAΔt--------+
ΔFin 1 2⁄+
+
Min 1+
Min
= 1DBΔt--------+
ΔMin 1 2⁄+
+
Materials20
Remarks:1. The axial and bending damping factors are used to damp down numerical noise. The update of the
force resultants, , and moment resultants, , includes the damping factors:
2. Fluid like behavior is obtained with the following relationship between bulk modulus, K, and pressure rate, p:
A tensor viscosity VC, if used, which acts only on the deviatoric stresses
See Also:• LS-DYNA Keyword User’s Manual
MAT_ELASTIC_PLASTIC_THERMAL
Temperature dependent material coefficients can be defined using this material type. A minimum of two temperature points are needed, and a maximum of eight can be defined.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
Fi Mi
Fin 1+
Fin
= 1DAΔt--------+
ΔFin 1 2⁄+
+
Min 1+
Min
= 1DBΔt--------+
ΔMin 1 2⁄+
+
KE
3 1 2υ–( )------------------------=
p Kε··ii–=
21MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_ISOTROPIC_ELASTIC_PLASTIC
Defines an isotropic plasticity material with isotropic hardening. This is a very low cost plasticity model, suitable for 3D solids and plane stress elements. If used in shell elements, this material model leads to inaccurate shell thickness updates and stresses after yielding.
MID Material identification number (Integer > 0)
RO Mass Density of the material
YM_LC Load curve defining Young’s modulus Vs. Temperatures.
PR_LC Load curve defining Poisson’s raito Vs. Temperatures.
A_LC Load curve defining the coefficent of thermal expansion Vs. Temperatures.
SIGY_LC Load curve defining Yield stressVs. Temperatures.
V_LC Load curve defining the plastic hardening modulus Vs. Temperatures.
Field Contents
Name Unique name identifying the material model.
Desc Optional description of the material model.
Fields:
MID Material identification number. (Integer > 0)
RO Mass density.
G Shear modulus.
SIGY Yield Stress.
ETAN Plastic hardening modulus
BULK Bulk modulus
Field Comments
Materials22
Remarks:1. In the plane stress implementation for shell elements, a one-step radial return approach is used to
scale the Cauchy stress tensor if the state of stress exceeds the yield surface.
See Also:• LS-DYNA Keyword User’s Manual
MAT_LOW_DENSITY_FOAM
This material is used to model highly compressible low density foams. Its main applications are for seat cushions and padding on the Side Impact Dummies (SID). Optionally, a tension cut-off failure can be defined.
Field Contents
Name Unique name identifying the material model.
Desc Optional description of the material model.
Fields:
MID Material identification number. (Integer > 0)
RO Mass density.
E Young’s modulus
LCID Load Curve Id for nominal stress versus strain
TC Tension cut-off stress
HU Hysteric unloading factor (between 0 and 1). Default is 1 (no energy dissipation)
BETA Decay constant (β) for creep in unloading
23MaterialsMaterials
Remarks:
The compressive behavior is illustrated in Figure 1 where hysteresis on unloading is shown. This behavior under uniaxial loading is assumed not to significantly couple in the transverse directions. In tension the material behaves in a linear fashion until tearing occurs. Although the implementation may be somewhat unusual, it was motivated by Storakers (1986).
The model uses tabulated input data for the loading curve where the nominal stresses are defined as a function of the elongations, , which are defined in terms of the principal stretches, , as:
DAMP Viscous damping coefficient (0.05< recommended value < 0.50) to model damping effects.
LT. 0: the absolute value of DAMP is used as the load curve which defines the damping coefficient as a function of the maximum strain in compression εmax (see Remark 1). In tension, the damping constant is set to the value corresponding to the strain at 0.
SHAPE Shape factor for unloading. Active for non-zero values of the Hysteric unloading factor (HU)
FAIL Failure option, after cut-off stress reached.
= 0, Tensile stress remains at cut-off value
= 1, Tensile stress is reset to zero
BVFLAG Bulk viscosity activation flag
= 0, No bulk viscosity (recommended, default)
= 1, Bulk viscosity active
ED Young’s relaxation modulus Ed (optional), for rate effects.
BETA1 Optional Decay constant β1
KCON Stiffness coefficient for contact interface stiffness. If undefined, the maximum slope in the stress vs. strain curve is used.
REF Use Reference geometry to initialize the stress tensor. The reference geometry is defined by the keyword: *INITIAL_FOAM_REFERENCE_GEOMETRY.
= 0, Off
= 1, On
Field Contents
εi λi
εi λi 1–=
Materials24
The stretch ratios are found by solving for the eigenvalues of the left stretch tensor, , which is obtained
via a polar decomposition of the deformation gradient matrix, . Recall that,
The update of follows the numerically stable approach of (Taylor and Flanagan 1989). After solving
for the principal stretches, we compute the elongations and, if the elongations are compressive, the corresponding values of the nominal stresses, are interpolated. If the elongations are tensile, the
nominal stresses are given by
and the Cauchy stresses in the principal system become
The stresses can now be transformed back into the global system for the nodal force calculations.
Additional Remarks:1. When hysteretic unloading is used the reloading will follow the unloading curve if the decay
constant, , is set to zero. If is nonzero the decay to the original loading curve is governed by the expression:
2. The bulk viscosity, which generates a rate dependent pressure, may cause an unexpected volumetric response and, consequently, it is optional with this model.
3. The hysteretic unloading factor results in the unloading curve to lie beneath the loading curve as shown below. This unloading provide energy dissipation which is reasonable in certain kinds of foam.
4. Note that since this material has no effective plastic strain, the internal energy per initial volume is written into the output databases.
5. Rate effects are accounted for through linear viscoelasticity by a convolution integral of the form
where is the relaxation function.
The stress tensor augments the stresses determined from the foam. Consequently, the final stress, is taken as the summation of the two contributions:
Vij
Fij
Fij RikUkj VikRkj= =
Vij
τi
τi Eεi=
σi
τi
λiλk----------=
β β
1. eβt–
–
σijr
gijkl0
t
t τ–( )∂εkl
∂τ---------dτ=
gijkl t τ–( )
σi j
σij σijf σij
r+=
25MaterialsMaterials
Since we wish to include only simple rate effects, the relaxation function is represented by one term from the Prony series:
given by,
This model is effectively a Maxwell fluid which consists of a damper and spring in series. We characterize this in the input by a Young's modulus, , and decay constant, .The formulation is performed in the local system of principal stretches where only the principal values of stress are computed and triaxial coupling is avoided. Consequently, the one-dimensional nature of this foam material is unaffected by this addition of rate effects. The addition of rate effects necessitates twelve additional history variables per integration point. The cost and memory overhead of this model comes primarily from the need to “remember” the local system of principal stretches.
Figure 1 Behavior of the Low Density Urethane Foam Model
6. The time step size is based on the current density and the maximum of the instantaneous loading slope, E, and ECON. If ECON is undefined the maximum slope in the loading curve is used instead.
See Also:• LS-DYNA Keyword User’s Manual
g t( ) α0 ameβt–
m 1=
N
+=
g t( ) Edeβ1t–
=
Ed β1
Materials26
MAT_MOONEY_RIVLIN_RUBBER
This LS-DYNA material is used to define material properties for a two-parameter material model for rubber.
Remarks:
The strain energy density function is defined as:
Field Contents
Name Unique name identifying the material model.
Desc Optional description of the material model.
Fields:
MID Material identification number. (Integer > 0)
PR Poisson’s ratio.
RO Mass density.
A Mooney Rivlin Constant, A
B Mooney Rivlin Constant, B
REF Use Reference geometry to initialize the stress tensor
=0, Off
= 1, On
SGL Specimen Gauge length, l0SW Specimen width
ST Specimen thickness
LCID Load Curve Id defining the force versus actual length change (ΔL) in the gauge length.
W A I 3–( ) B II 3–( ) C III2–
1–( ) D III 1–( )2+ + +=
27MaterialsMaterials
C = 0.5A + B
D = A(5ν - 2) + B(11ν -5)/(2(1 - 2ν))
ν = Poisson’s ratio
2(A + B) = Shear modulus of linear elasticity
I, II, III are the three invariants of the Cauchy-Green Tensor
The load curve definition that provides the uniaxial data should give the change in gauge length, ,
versus the corresponding force. In compression both the force and the change in gauge length must be specified as negative values. In tension the force and change in gauge length should be input as positive values. The principal stretch ratio in the uniaxial direction, , is then given by
with L0 being the initial length and L being the actual length.
Alternatively, the stress versus strain curve can also be input by setting the gauge length, thickness, and width to unity (1.0) and defining the engineering strain in place of the change in gauge length and the nominal (engineering) stress in place of the force (Figure 2).
ΔL
λ1
λ1
L0 ΔL+
L0-------------------=
Materials28
Figure 2 Uniaxial Specimen for Experimental Data
The least square fit to the experimental data is performed during the initialization phase and is a comparison between the fit and the actual input is provided in the printed file. It is a good idea to visually check to make sure that it is acceptable. The coefficients A and B are also printed in the Dyna output file.
The stress versus strain curve can used instead of the force versus the change in the gauge length by setting the gauge length, thickness, and width to unity (1.0) and defining the engineering strain in place of the change in gauge length and the nominal (engineering) stress in place of the force (Figure 3).
Figure 3 Experimental Data from Uniaxial Specimen
See Also:• LS-DYNA Keyword User’s Manual
29MaterialsMaterials
MAT_NONLOCAL
Defines failure criterion to be dependent on the state of the material within a radius of influence which surrounds the integration point. With this failure model, the mesh size sensitivity of failure is greatly reduced, giving better convergence to a unique solution as the mesh is refined.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Non local Material identification number (Integer > 0)
PID Part Id for non local material
P Exponent of weighting function. A typical value might be 8., depending on the choice of the value for L.
Q Exponent of weighting function. A typical value might be 2.
L Characteristic length. This length should span a few elements
NFREQ Number of time steps before updating neighbors. Since the nearest neighbor search can add significant computational time, NFREQ should be set to value of 10 to 100.
NL1,,, NL8 History variable Ids for non local treatment
XC1, YC1, ZC1 Coordinate of point on symmetry plane
XC2, YC2, ZC2 Coordinate of a point along the normal vector
Materials30
MAT_ORTHOTROPIC_ELASTIC
This LS_Dyna material model (002) is an orthotropic elastic material available for solids, shells, and thick shells.
Field Contents
Title Unique name identifying the material model.
Desc Optional description of the material model.
TITLE_OPTION If selected, the material Title will be exported to LS-DYNA
MID Material identification number. (Integer > 0)
RO Mass density.
EA Young’s modulus in a-direction
EB Young’s modulus in b-direction
EC Young’s modulus in c-direction
PRBA Poisson’s ratio (νba)
PRCA Poisson’s ratio (νca)
PRCB Poisson’s ratio (νcb)
GAB Shear modulus (Gab)
GBC Shear modulus (Gbc)
GCA Shear modulus (Gca)
AOPT Material axis option
G Shear modulus for frequency dependent damping
SIGF Limit stress for frequency independent frictional damping
XP, YP, ZP Coordinates for point P (for AOPT= 1 and 4)
31MaterialsMaterials
Remarks:
The material law that relates stresses to strains is defined as:
where is a transformation matrix, and is the constitutive matrix defined in terms of the material
constants of the orthogonal material axes, , , and . The inverse of for the orthotropic case is
defined as:
Note that
A1, A2, A3 Components of a vector a (for AOPT=2)
D1, D2, D3 Components of a vector d (for AOPT=2)
V1, V2, V3 Components of a vector v (for AOPT= 3 and 4)
BETA Material angle in degrees (for AOPT= 3)
REF Use Reference geometry to initialize the stress tensor
Field Contents
C˜
T˜
TC˜ LT
˜=
T˜
C˜ L
a b c C˜ L
C˜ L
1–
1Ea------
νba
Eb--------–
νca
Ec-------– 0 0 0
νab
Ea--------–
1Eb------
νcb
Ec-------– 0 0 0
νac
Ea-------–
νbc
Eb-------–
1Ec----- 0 0 0
0 0 01
Gab--------- 0 0
0 0 0 01
Gbc--------- 0
0 0 0 0 01
Gca---------
=
νab
Ea--------
νba
Eb--------
νca
Ec-------,
νac
Ea-------
νcb
Ec-------,
νbc
Eb-------= = =
Materials32
The frequency independent damping is obtained by having a spring and slider in series as shown in the following sketch:
This option applies only to orthotropic solid elements and affects only the deviatoric stresses.
See Also:• LS-DYNA Keyword User’s Manual
MAT_PIECEWISE_LINEAR_PLASTICITY
Defines elasto-plastic material with an arbitrary stress versus strain curve and arbitrary strain rate dependency. Also, failure based on a plastic strain or a minimum time step size can be defined.
Field Contents
Name Unique name identifying the material model.
Desc Optional description of the material model.
Fields:
MID Material identification number. (Integer > 0)
E Young’s modulus. (Real > 0.0 or blank)
PR Poisson’s ratio.
RO Mass density.
SIGY Yield Stress.
ETAN Tangent modulus (ignored if LCSS.GT. 0 is defined)
G
σfric
33MaterialsMaterials
Remarks:
The stress strain behavior may be treated by a bilinear stress strain curve by defining the tangent modulus, ETAN. The most general approach is to use the table definition (LCSS) discussed below.
Three options to account for strain rate effects are possible.
1. Strain rate may be accounted for using the Cowper and Symonds model which scales the yield stress with the factor
where, is the strain rate
If VP=-1, the deviatoric strain rates are used instead.
If the viscoplastic option is active, VP=1.0, and if SIGY is > 0 then the dynamic yield stress is computed from the sum of the static stress,
FAIL Failure Flag
LT. 0: User defined failure subroutine is called to determine failure
EQ. 0.0: Failure not considered
GT. 0.0: Plastic strain to failure. When the plastic strain reaches this value, the element is deleted from the calculation.
TDEL Minimum time step size for automatic element deletion
C Strain rate parameter, C
P Strain rate parameter, P
LCSS Load Curve Id or Table Id defining effective stress versus effective plastic strain. The tableId defined for each strain rate a value of load curve Id giving the stress versus effective plastic strain for that rate.
LCSR Load Curve Id defining strain rate scaling effect on yield stress
VP Formulation for rate effects
=-1, Cowper-Symnods with deviatoric strain rate rather than total
= 0, Scale yield stress
= 1, Viscoplastic formulation
Field Contents
1ε·
C----
1 p⁄+
ε·
ε· ε· ijε·
ij=
Materials34
which is typically given by a load curve ID, and the initial yield stress, SIGY, multiplied by the Cowper-Symonds rate term as follows:
where the plastic strain rate is used. If SIGY=0, the following equation is used instead where the static stress
must be defined by a load curve:
This latter equation is always used if the viscoplastic option is off.
2. For complete generality a load curve (LCSR) to scale the yield stress may be input instead. In this curve the scale factor versus strain rate is defined.
3. If different stress versus strain curves can be provided for various strain rates, the option using the reference to a table (LCSS) can be used. See figure below.
σys εeff
p( )
σy εeffp ε· eff
p,( ) σy
s εeffp( ) SIGY
ε· effp
C-------
1 p⁄
⋅+=
σys εeff
p( )
σy εeffp ε· eff
p,( ) σy
s εeffp( ) 1
ε· effp
C-------
1 p⁄
+=
35MaterialsMaterials
Figure 4 Rate effects may be accounted for by defining a table of curves. If a table Id is specified a curve Id is given for each strain rate. Intermediate values are found by interpolating between curves. Effective plastic strain versus yield stress is expected. If the strain rate values fall out of range, extrapolation is not used; rather, either the first or last curve determines the yield stress depending on whether the rate is low or high, respectively.
4. A fully viscoplastic formulation is optional (variable VP) which incorporates the different options above within the yield surface. An additional cost is incurred over the simple scaling but the improvement in results can be dramatic.
See Also:• LS-DYNA Keyword User’s Manual
Materials36
MAT_PLASTIC_KINEMATIC
Defines elasto-plastic material with isotropic and kinematic hardening with or without rate effects.
Field Contents
Name Unique name identifying the material model.
Desc Optional description of the material model.
Fields:
MID Material identification number. (Integer > 0)
E Young’s modulus. (Real > 0.0 or blank)
PR Poisson’s ratio.
RO Mass density.
SIGY Yield Stress.
ETAN Tangent modulus
BETA Hardening parameter
= 0: Kinematic hardening
= 1: Isotropic hardening
1 < BETA > 0: Combined hardening
SRC Strain rate parameter, C, for Cowper Symonds strain rate model. If zero, rate effects are ignored.
SRP Strain rate parameter, P, for Cowper Symonds strain rate model. If zero, rate effects are ignored.
FS Failure strain for eroding elements
VP Formulation for rate effects:
= 0, Scale yield stress (default)
= 1, Viscoplastic formulation
37MaterialsMaterials
Remarks:
Figure 5 Elastic-plastic behavior with kinematic and isotropic hardening where l0 and l are respectively undeformed and deformed lengths of uniaxial tension specimen, and Et is the slope of the bilinear stress vs. strain curve.
Strain rate may be accounted for using the Cowper and Symonds model which scales the yield stress with the factor
where, is the strain rate
1ε·
C----
1 p⁄+
ε·
Materials38
A fully viscoplastic formulation is optional which incorporates the Cowper and Symonds formulation within the yield surface. Although an additional computational cost is incurred, the improvement in the results can be substantial. To ignore strain rate effects, set both SRC and SRP to zero.
See Also:• LS-DYNA Keyword User’s Manual
MAT_POWER_LAW_PLASTICITY
Defines an isotropic plasticity material model with rate effects which uses a power law for hardening.
Field Contents
Name Unique name identifying the material model.
Desc Optional description of the material model.
Fields:
MID Material identification number. (Integer > 0)
RO Mass density.
E Young’s modulus. (Real > 0.0 or blank)
PR Poisson’s ratio.
K Strength coefficient
N Hardening exponent
SRC Strain rate parameter, C. If zero, rate effects are ignored.
SRP Strain rate parameter, P. If zero, rate effects are ignored.
ε· ε· ijε·
ij=
39MaterialsMaterials
Remarks:
The yield stress, σy is a function of plastic strain, and obeys the following equation:
where, yp is the strain rate to yield, and p is the effective plastic strain (logarithmic).
The parameter SIGY governs how the strain to yield is identified. If SIGY is set to zero, the strain to yield is found by solving for the intersection of the linear elastic loading with the strain hardening equation:
which gives the elastic strain at yield as:
If SIGY is set to nonzero, and greater than 0.02 then:
SIGY Yield Stress (optional). Generally this parameter is not necessary (See Remarks)
VP Formulation for rate effects:
= 0, Scale yield stress (default)
= 1, Viscoplastic formulation
Field Contents
( )nn py ypk kσ ε ε ε= = +
ε· ε
n
E
k
σ εσ ε
==
1
1n
yp
E
kε
− =
1
ny
yp k
σε
=
Materials40
Strain rate is accounted for using the Cowper-Symonds model which scales the yield stress with the following factor:
where is the strain rate. A fully viscoplastic formulation is optional with this model which incorporates
the Cowper-Symonds formulation within the yield surface. Although an additional cost is incurred, the improvement in results can be substantial.
See Also:• LS-DYNA Keyword User’s Manual
MAT_RIGID
This material model is used to model parts made from rigid materials. Also, the coupling of a rigid body with MADYMO, and CAL3D can be defined via this material. Alternatively, a VDA surface can be attached as surface to model the geometry, e.g., for the tooling in metal-forming applications. Also, global and local constraints on the mass center can be optionally defined. Optionally, a local consideration for output and user-defined airbag sensors can be chosen.
Field Contents
Title Unique name identifying the material model.
Desc Optional description of the material model.
TITLE_OPTION If selected, the material Title will be exported to LS-DYNA
MID Material identification number. (Integer > 0)
1
1P
Cε +
ε·
41MaterialsMaterials
RO Mass density
E Young’s modulus. (Real > 0.0 or blank)
PR Poisson’s ratio
N MADYMO3D coupling flag.
COUPLE Coupling Option
ALIAS VDA Surface alias Name
CMO Center of mass constraint option
=1, Constraints applied in global directions
=0, No constraints
=-1, Constraints applied in local directions
CON1 First constraint parameter
=0, No constraints
=1, Constrained x displacement
=2, Constrained y displacement
=3, Constrained z displacement
=4, Constrained x and y displacements
=5, Constrained y and z displacements
=6, Constrained z and x displacements
=7, Constrained x, y, and z displacements
Field Contents
Materials42
Remarks:1. A rigid material provides a convenient way of turning one or more parts comprised of beams,
shells, or solid elements into a rigid body. Approximating a deformable body as rigid is a preferred modeling technique in many real world applications. For example, an engine block in a car crash simulation can be treated as rigid. Elements belonging to a rigid material are bypassed in the element processing and no storage is allocated for storing history variables. Consequently, using a rigid material is very cost efficient.
2. The inertial properties are calculated from the geometry of the constituent elements and the density RO as specified on the MAT_RIGID.
3. The initial velocity of a rigid material is calculated from the initial velocity of the constituent grids.
4. A rigid body can be made up of disjoint meshes. All elements that are part of a rigid body will move together as one rigid, even if they are disjoint.
5. Motion control for a rigid material can be defined using the BOUNDARY_SPC entry. The SPC must be applied to one grid point only.
6. Load control for a rigid material can be defined using the FORCE and MOMENT entries. These loads can be applied to any grid point that belongs to the rigid body. The forces and moments acting on the grid points will be accumulated and applied to the rigid body.
7. If no constraints are specified for the rigid material (CMO=0) the nodes belonging to the rigid material are scanned to determine constraints of the rigid material in global directions. If constraints are specified for the rigid material (CMO equal to +1 or –1), the nodes belonging to the rigid material are not scanned
CON2 Second constraint parameter
=0, No constraints
=1, Constrained x rotation
=2, Constrained y rotation
=3, Constrained z rotation
=4, Constrained x and y rotations
=5, Constrained y and z rotations
=6, Constrained z and x rotations
=7, Constrained x, y, and z rotations
LCO Local coordinate system for output
A1-V3 The components of two vectors a and v fixed in the rigid body for output.
Field Contents
43MaterialsMaterials
8. Constraint directions for rigid materials (CMO equal to +1 or –1) are fixed, that is, not updated, with time.
See Also:• LS-DYNA Keyword User’s Manual
MAT_SEATBELT
This material model is used to define the stretch characteristics and mass properties for seat belts.
Remarks:1. The Load curves for loading and unloading should start at the origin (0, 0), and contain positive
force and strain values only. The belt material is tension only, with zero forces being calculated whenever the strain becomes negative (compressive). The first nonzero point on the loading curve defines the initial yield point of the material. On unloading, the unloading curve is shifted along the strain axis until it crosses the loading curve at the yield point from which unloading starts. If the initial yield has not yet exceeded, or the origin of the (shifted) unloading curve is at negative strain, the original loading curve will be used for both loading and unloading. If the strain is less than the strain at the origin of the unloading curve, the belt is slack, and no force is generated. Otherwise, forces will be determined by the unloading curve for unloading, and reloading until the strain again exceeds yield after which the loading curve will again be used.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
MPUL Mass per unit length
LLCID Load curve Id for loading (Force vs. engineering strain)
ULCID Load curve Id for unloading (Force vs. engineering strain)
LMIN Minimum length for elements connected to slip rings and retractors
Materials44
2. A small amount of damping is automatically included, to reduce high frequency oscillation. The damping force, D opposes the relative motion of the nodes, and is limited by stability:
D = (0.1 X Mass X Relative velocity)/(Time step size)
The magnitude of the damping force is limited to one-tenth of the force calculated from the force vs. strain relationship, and is zero when the belt is slack. Damping forces are not applied to elements attached to slip rings and retractors.
See Also:• LS-DYNA Keyword User’s Manual
MAT_SOIL_AND_FOAM
This simple material model works similar to fluid. It should be used only in situations when soils and foams are confined within a structure or when geometric boundaries are present.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear modulus
BULK Bulk modulus for unloading
A0, A1, A2 Yield function constants
PC Pressure cut off for tensile fracture
VCR Volumetric crushing option:
0.0: on,
1.0: loading and unloading paths are the same
45MaterialsMaterials
Remarks:1. Pressure is positive in compression
2. Volumetric strain is given by the natural log of the relative volume and is negative in compression
3. Relative volume is the ratio of current volume to the initial volume at the start of the calculation
4. If the pressure drops below the cutoff value specified, it is reset to that value
See Also:• LS-DYNA Keyword User’s Manual
MAT_VISCOELASTIC
This material model is used to define viscoelastic behavior for beams (Hughes-Liu), shells, and solids
Remarks:1. The shear relaxation behavior is described by [Hermann and Peterson, 1968]:
REF use reference geometry to initialize the pressure
LCID Load curve Id defining pressure vs. volumetric strain
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
BULK Bulk modulus for unloading
G0 Short time shear modulus
GI long time (Infinite) Shear modulus
BETA Decay constant
Field Comments
G t( ) GI G0 GI–( )eβt–
+=
Materials46
See Also:• LS-DYNA Keyword User’s Manual
MAT_HIGH_EXPLOSIVE_BURN
This material model is used to input the detonation properties of high explosive materials.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
D Detonation Velocity
PCJ Chapman-Jouget pressure
BETA Beta burn flag
0: Beta and programmed burn
1: Beta burn only
2: Programmed burn only
K Bulk Modulus (Beta = 2)
G Shear Modulus (Beta = 2)
SIGY Yield Stress (Beta = 2)
47MaterialsMaterials
MAT_NULL
The use of this material model allows equations of state without computing deviatoric stresses.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
PC Pressure Cutoff
MU Dynamic Viscosity Coefficient
TEROD Relative Volume for Erosion in Tension
CEROD Relative Volume for Erosion in Compression
YM Young’s Modulus (used for null beams and shells only)
PR Poisson’s ratio (used for nul beams and shells only)
Materials48
MAT_ELASTIC_PLASTIC_HYDRO
This material model is used to model an elastic-plastic hydrodynamic material.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear Modulus
SIGY Yield Stress
EH Plastic hardening modulus
PC Pressure Cutoff
FS Failure strain for Erosion
LCID Load curve Id defining pressure vs. volumetric strain
49MaterialsMaterials
MAT_ELASTIC_PLASTIC_HYDRO_SPALL
This material model is used to model an elastic-plastic hydrodynamic material with spall to represent splitting, cracking, and failure under tensile loads.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear Modulus
SIGY Yield Stress
EH Plastic hardening modulus
PC Pressure Cutoff
FS Failure strain for Erosion
A1 Linear Pressure Hardening Coefficient
A2 Quadratic Pressure Hardening Coefficient
SPALL Spall Type
LCID Load curve Id defining pressure vs. volumetric strain
Materials50
MAT_STEINBERG
This material model is used to model materials deforming at very high strain rate for use with solid elements. The yield strength is a function of temperature and pressure.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G0 Basic shear modulus
SIG0 Yield Stress, σ0
BETA Parameter β, used in the equation defining Yield Strength
N Parameter n, used in the equation defininig Yield Strength
GAMA Initial Plastic Strain γi
SIGM σm
B Parameter b, used in the equation defininig Yield Strength
BP Parameter , used in the equation defininig Yield Strength
H Parameter h, used in the equation defininig Yield Strength
F Parameter b, used in the equation defininig Yield Strength
A Atomic Weight
TM0 Melting Temperature
b'
51MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
GAM0 Yield Stress equation Parameter, Gama_0
SA Melting Temperature equation Parameter, a
PC Pressure Cutoff
SPALL Spall Type
0: Default set to 2.0
1: P >= PC
2: if σmax >= -PC, element spalls and tension, p < 0, is never allowed
3: P< -PC, element spalls and tension, p < 0, is never allowed
RP Melting Temperature equation parameter,
FLAG Set 1 for μ coefficients for the cold compression energy fit
NMN Optional minimum value for μ or ηNMX Optional maximum value for μ or ηECi Cold Compression Energy coefficients
Field Comments
r'
Materials52
MAT_STEINBERG_LUND
This material model is used to input the properties of a Steinberg and Lund [1999].material model for including the strain rate effect.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G0 Basic shear modulus
SIG0 Yield Stress, σ0
BETA Parameter β, used in the equation defininig Yield Strength
N Parameter n, used in the equation defininig Yield Strength
GAMA Initial Plastic Strain γi
SIGM σm
B Parameter b, used in the equation defininig Yield Strength
BP Parameter , used in the equation defininig Yield Strength
H Parameter h, used in the equation defininig Yield Strength
F Parameter b, used in the equation defininig Yield Strength
b'
53MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
A Atomic Weight
TM0 Melting Temperature
GAM0 Yield Stress equation Parameter, Gama_0
SA Melting Temperature equation Parameter, a
PC Pressure Cutoff
SPALL Spall Type
0: Default set to 2.0
1: P >= PC
2: if σmax >= -PC, element spalls and tension, p < 0, is never allowed
3: P< -PC, element spalls and tension, p < 0, is never allowed
RP Melting Temperature equation parameter,
FLAG Set 1 for μ coeeficients for the cold compression energy fit
NMN Optional minimum value for μ or ηNMX Optional maximum value for μ or ηECi Cold Compression Energy coefficients
UK Activation Energy for rate dependent model
C1 Exponent prefactor in rate dependent model
C2 Coefficient of drag term rate dependent model
YP Peierls stress for rate dependent model
YA Ahtermal yield stress for rate dependent model
YM Work hardening max for rate dependent model
Field Comments
r'
Materials54
MAT_ISOTROPIC_ELASTIC_FAILURE
This material model is used to define the properties of a non-iterative plasticity model with simple plastic strain failure criteria.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear Modulus
SIGY Yield Stress
ETAN Plastic Hardening Modulus
BULK Bulk Modulus
EPF Plastic Failure Strain
PRF Failure Pressure
REM Element Erosion option
0: Eroded at failure
1: no removal of element, (except if TERM = 1, and element time step size falls below Δt)
TREM Δt for element removal
0: Δt is not considered
1: yes, if element time step size falls below Δt
55MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_SOIL_AND_FOAM_FAILURE
This material model is used to define the material properties for a soil and foam model. This material model works similar to fluid, and should be used only in situations when soils and foams are confined within a structure or when geometric boundaries are present.In this material model, the material loses its ability to carry tension when the pressure exceeds the failure pressure.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear Modulus
BULK Bulk Modulus for unloading
A0, A1, A2 Plastic Yield Function Constants
PC Pressure Cutoff for Tensile Fracture
VCR Volumetric Crushing Option
0: On
1: Loading and unloading paths are the same
Materials56
See Also:• LS-DYNA Keyword User’s Manual
MAT_JOHNSON_COOK
The Johnson-Cook material model is a strain and temperature sensitive plasticity model. It is sometimes used for materials with a large variation in the strain rate, and/or undergoing softening due to plastic heating.
REF Use reference geometry to initialize pressure
0: Off
1:On
LCID Load Curve Id defining pressure vs. volumetric strain
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear Modulus
Field Comments
57MaterialsMaterials
E Young’s Modulus (for shell elements only)
PR Poisson’s Ratio (for shell elements only)
DTF Minimum Time step for Automatic Shell Element Deletion
VP Formulation for Rate Effects
0: Scale Yield Stress
1: ViscoPlastic Formulation
RATEOP Optional forms of strain-rate term:
.EQ. 0: Log-Linear Johnson-Cook (default)
.EQ. 1: Log-Quadratic Huh-Kang (2 parameters)
.EQ. 2: Exponential Allen-Rule_jones
.EQ. 3: Exponential Cowper-Symonds (2 parameters)
A, B, N, C, M Constants to define the flow stress equation
TM Melt Temperature
TR Room Temperature
EPSO Effective Plastic Strain Rate depends on Time Unit
CP Specific Heat
PC Pressure Cutoff (Pmin< 0.0)
SPALL Spall Type
0: Default set to 2.0
1: P >= PC
2: if σmax >= -PC, element spalls and tension, p < 0, is never allowed
3: P< -PC, element spalls and tension, p < 0, is never allowed
IT Plastic Strain Iteration
0: No Iteration
1: Accurative Iteration Solution
Di Failure Parameters
C2/P Optional strain-rate parameter for Huh-Kang (C2), or Cowper-Symonds (P) forms.
Field Comments
Materials58
See Also:• LS-DYNA Keyword User’s Manual
MAT_PSEUDO_TENSOR
This material model is used to define the properties a pseudo-tensor material model. This has been used to analyze buried steel reinforced concrete structures subjected to impulsive loadings.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear Modulus
PR Poisson’s Ratio
SIGF Tension Cutoff (Maximum Principal Stress at failure)
A0 Cohesion
A1, A2 Pressure Hardening Coefficients
A0F Cohesion for failed material
A1F Pressure hardening coefficient for failed material
B1 Damage Scaling Factor
PER Percent Reinforcement
59MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_ORIENTED_CRACK
Defines the properties of brittle materials failing due to large tensile stresses.
ER Young’s Modulus for Reinforcement
PRR Poisson’s Ratio for Reinforcement
SIGY Initial Yield Stress
ETAN Tangent Modulus/Plastic Hardening Modulus
LCP Load Curve Id defining rate sensitivity for principal material
LCR Load Curve Id defining rate sensitivity for reinforcement
LCID Load Curve defining Yield Stress (or scale factor) vs. effective plastic strains, damages, or pressures
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Plastic Hardening Modulus
FS Fracture Stress
PRF Fracture Pressure
Field Comments
Materials60
See Also:• LS-DYNA Keyword User’s Manual
MAT_STRAIN_RATE_DEPENDENT_PLASTICITY
Defines the properties of a strain rate dependent material.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
VP Formulation for Rate Effects
0: Scale Yield Stress
1: Viscoplastic Formulation
LC1 Load Curve Id for Yield Stress σ0 vs. effective strain rate
ETAN Tangent Modulus
LC2 Load Curve Id for Young’s Modulus vs. effective strain rate
LC3 Load Curve Id for Tangent Modulus vs. effective strain rate
LC4 Load Curve Id for von Mises stress at failure vs. effective strain rate
TDEL Time Step Size for Automatic Element Deletion (shell elements only)
RDEF Redefinition of failure curve
1: Effective plastic strain
2: Maximum principal stress
61MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_ORTHOTROPIC_THERMAL
Defines the properties of a linear elastic material with temperature dependent orthotropic properties.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EA, EB, EC Young’s Moduli in the A, B and C direction
PRBA, PRCA, PRCB Poisson’s Ratio in the ba, ca and cb directions
GAB, GBC, GCA Shear Moduli in the ab, bc and ca directions
AA, AB, AC Coefficients of Thermal Expansion in the a, b, and c directions
Materials62
See Also:• LS-DYNA Keyword User’s Manual
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of local c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
4: Locally orthotropic in cylindrical coordinate system with the material axis determined by a vector v, and an originating point, P, which defines the center line axis. This option is for solid elements only.
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT = 3
REF Use Reference Geometry to initialize stress tensor (0 = off; 1 = on)
Field Comments
63MaterialsMaterials
MAT_COMPOSITE_DAMAGE
Defines the properties of an orthrotropic material with optional brittle failure for composites.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EA, EB, EC Young’s Moduli in the A, B and C direction
PRBA, PRCA, PRCB Poisson’s Ratio in the ba, ca and cb directions
GAB, GBC, GCA Shear Moduli in the ab, bc and ca directions
KF Bulk Modulus of failed material
Materials64
See Also:• LS-DYNA Keyword User’s Manual
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
4: Locally orthotropic in cylindrical coordinate system with the material axis determined by a vector v, and an originating point, P, which defines the centerline axis. This option is for solid elements only.
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Material Angle
SC Shear Strength, ab plane
XT Longitudinal Tensile Strength, a-axis
YT Transverse Tensile Strength, b-axis
YC Transverse Compression Strength, b-axis
ALPH Shear Stress Parameter for nonlinear term (0- 0.5)
SN Normal Tensile Strength (solid elements only)
SYX Transverse Shear Strength (solid elements only)
SZX Transverse Shear Strength (solid elements only)
Field Comments
65MaterialsMaterials
MAT_TEMPERATURE_DEPENDENT_ORTHOTROPIC
Defines the properties of an orthotropic elastic material with arbitrary temperature dependency.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
Materials66
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
4: Locally orthotropic in cylindrical coordinate system with the material axis determined by a vector v, and an originating point, P, which defines the centerline axis. This option is for solid elements only.
REF Use Reference Geometry to initialize stress tensor (0 = off; 1 = on)
MACF Material axes change flag for brick element:
=1 No Change; = 2 switch mateial axes a and b
=3 switch material axes a and c ; =4 switch material axes b and c
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Material Angle
EA_LC, EB_LC, EC_LC
Load curve defining Young’s Moduli in the a, b and c directions, respecively, vs. Temperature
PRBA_LC Load curve defining Poisson’s Ratios in the ba directionsvs. Temperature
PRCA_LC Load curve defining Poisson’s Ratios in the ca directionsvs. Temperature
PRCB_LC Load curve defining Poisson’s Ratios in the cb directionsvs. Temperature
Field Comments
67MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_GEOLOGIC_CAP_MODEL
Defines the properties for geomechanical problems or materials like concrete.
AA_LC, AB_LC, AC_LC
Load curves defining Coefficients of Thermal Expansion in the a, b, and c directions, respectively, vs. Temperature
GAB_LC Load curve defining Shear modulus in the ab plane vs. Temperature
GBC_LC Load curve defining Shear modulus in the bc plane vs. Temperature
GCA_LC Load curve defining Shear modulus in the ca plane vs. Temperature
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
BULK Initial Bulk Modulus
G Initial Shear Modulus
ALPHA Failure Envelope Parameter
THETA Failure Envelope Linear coefficient
GAMMA Failure Envelope Exponential coefficient
BETA Failure Envelope Exponent
R Cap, surface axis ratio
Field Comments
Materials68
See Also:• LS-DYNA Keyword User’s Manual
D Hardening law exponent
W Hardening law coefficient
X0 Hardening Law Exponent
C Kinematic Hardening Coefficient
N Kinematic Hardening Parameter
PLOT Plotting Flag for LS-Taurus
FTYPE Formulation Flag
1: Soil or concrete
2: Rock
VEC Vectorization Flag
0: Vectorized with a fixed number of iterations
1: Fully Iterative
TOFF Tension Cutoff
Field Comments
69MaterialsMaterials
MAT_HONEYCOMB
Defines the properties for honeycomb and foam materials with real anisotropic behavior.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress for fully compacted Honeycomb
VF Relative Volume at which Honeycomb is fully compacted
MU Material Viscosity Coefficient
BULK Bulk Viscosity Flag
0: Bulk Viscosity Not Used
1: Bulk Viscosity Active and MU=0
LCA Load Curve Id for (Sigma_aa vs. either Relative Volume or Volumetric Strain
LCB Load Curve Id for (Sigma_bb vs. either Relative Volume or Volumetric Strain (Default LCB = LCA)
Materials70
See Also:• LS-DYNA Keyword User’s Manual
LCC Load Curve Id for (Sigma_cc vs. either Relative Volume or Volumetric Strain (Default LCC = LCA)
LCS Load Curve Id for (shear stress vs. either Relative Volume or Volumetric Strain (Default LCS = LCA)
LCAB Load Curve Id for (Sigma_ab vs. either Relative Volume or Volumetric Strain (Default LCAB = LCS)
LCBC Load Curve Id for (Sigma_bc vs. either Relative Volume or Volumetric Strain (Default LCBC = LCS)
LCCA Load Curve Id for (Sigma_ca vs. either Relative Volume or Volumetric Strain (Default LCCA = LCS)
LCSR Load Curve Id for strain rate effects defining the scale factor vs. strain rate. The curves defined above are scaled using this curve.
EAAU, EBBU, ECCU Elastic Moduli in uncompressed configuration in aa, bb, and cc directions
GABU, GBCU, GCAU Shear Moduli in uncompressed configuration in ab, bc, and ca planes
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
XP x-coordinate of point p, for AOPT = 1
YP y-coordinate of point p, for AOPT = 1
ZP z-coordinate of point p, for AOPT = 1
Ai Component of vector a, for AOPT = 2
Di Component of vector d, for AOPT = 2
TSEF Tensile Strain at Element Failure
SSEF Shear Strain at Element Failure
Field Comments
71MaterialsMaterials
MAT_RESULTANT_PLASTICITY
Defines a resultant formulation material model, including elastoplastic behavior.for beam and shell elements,
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Plastic Hardening Modulus (shell elements only)
Materials72
MAT_FORCE_LIMITED
This material model allows the simulation of plastic hinge formation at the ends of a beam, using a curve definition (for Belytschko-Schwer beam only).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
DF Damping Factor
AOPT Axial Load Curve Option
0: Force vs. Strain
1: Force vs. Change in Length
M1, M2,,,,, M8 Applied end moment for force vs. strain/ or change in length curve. A minimum of one, and a maximum of eight must be defined.
LC1, LC2, ..., LC8 Load Curve Ids applied end moment
73MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_SHAPE_MEMORY
Defines the superplastic response present in shape memory alloys (SMA).
LPSi Load Curve Id for plastic moment vs. rotation about s-axis at node i
SFSi Scale factor, plastic moment vs. rotation about s- axis at node i
YMSi Yield moment about s- axis at node i for interaction calculations
LPTi Load Curve Id for plastic moment vs. rotation about t-axis at node i
SFTi Scale factor, plastic moment vs. rotation about t- axis at node i
YMTi Yield moment about t- axis at node i for interaction calculations
LPR Load Curve Id for plastic torsional moment vs. rotation
SFR Scale factor for plastic torsional moment vs. rotation
YMR Torsional yield moment for interaction calculations
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIG_ASS Starting value for the forward phase transformation
Field Comments
Materials74
See Also:• LS-DYNA Keyword User’s Manual
MAT_FRAZER_NASH_RUBBER_MODEL
Defines rubber from uniaxial test data.
SIG_ASF Final value for the forward phase transformation
SIG_SAS Starting value for the reverse phase transformations
SIG_SAF Final value for the reverse phase transformation
EPSL Recoverable strain or maximum residual strain
ALPHA Parameter Measuring the difference between material response in tension and compression
YMRT Young’s Modulus for Martensite
LC_ASS Load Curve Id for Starting value of forward phase transformation
LC_ASF Load Curve Id for Final value of forward phase transformation
LC_SAS Load Curve Id for Starting value of reverse phase transformations
LC_SAF Load Curve Id for Final value of reverse phase transformation
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
Field Comments
75MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
RO Mass Density of the material
PR Poisson’s Ratio
C100, C200, C300, C400, C110, C210, C010, C020
Strain Energy Parameters
EXIT Exit option of strain limit
0: Stop if limit exceeds
1: Continue even if limit exceeds
EMAX Maximum Strain Limit
EMIN Minimum Strain Limit
REF Use Reference Geometry to initialize stress tensor
0: Off
1: On
SGL Specimen Gauge Length
SW Specimen Width
ST Specimen Thickness
LCID Load Curve Id defining Force vs. Actual Change in gauge Length
Field Comments
Materials76
MAT_LAMINATED_GLASS
Defines layered glass including polymeric layers.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EG Young’s Modulus for Glass
PRG Poisson’s Ratio for Glass
SYG Yield Strength for Glass
ETG Plastic Hardening Modulus for Glass
EFG Plastic Strain at Failure for Glass
EP Young’s Modulus for Polymer
PRP Poisson’s Ratio for Polymer
SYP Yield Strength for Polymer
ETP Plastic Hardening Modulus for Polymer
NUM_RFS Number of Integration Points of Material
F1, F2,, ..., FN Integration Point Material
Fi = 0: glass; Fi = 1: polymer
77MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_BARLAT_ANISOTROPIC_PLASTICITY
Defines the properties of an anisotropic material behavior during forming processes.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
K Strength Coefficient
E0 Strain corresponding to initial yield
N Hardening exponent for yield strength
M Flow potential exponent in Barlat’s model
A, B, C, F, G, H Anisotropic Coefficients in Barlat’s model
LCID Load Curve Id defining effective Stress vs. effective Plastic Strain
Materials78
See Also:• LS-DYNA Keyword User’s Manual
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by offsetting the material axes by an angle, OFFANG, from a line defined by the cross product of the vector v with the normal to the plane of a shell element, or mid surface of a brick element.
BETA Offset angle (for AOPT = 3)
MACF Material axes change flag for brick element:
=1 No Change; = 2 switch mateial axes a and b
=3 switch material axes a and c ; =4 switch material axes b and c
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
Field Comments
79MaterialsMaterials
MAT_BARLAT_YLD96
Defines the properties of an anisotropic material behavior during forming processes, especially for aluminum alloys (only for shell elements only).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
K Strength Coefficient
E0 Strain corresponding to initial yield
N Hardening exponent for yield strength
ESRO εSRO, in power law rate sensitivity
M Exponent, m for strain rate effects
Materials80
See Also:• LS-DYNA Keyword User’s Manual
HARD Hardening option
<0: Absolute value defines the Load Curve Id
1:Powerlaw
2: Voce
A Flow Potential Exponent
Ci Equation parameters
AX Equation parameter
AY Equation Parameter
AZ0 Equation Parameter
AZ1 Equation Parameter
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by offsetting the material axes by an angle, OFFANG, from a line defined by the cross product of the vector v with the normal to the plane of the element.
OFFANG Offset Angle for AOPT = 3
blank1, blank2, blank3 Blank Fields
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
Field Comments
81MaterialsMaterials
MAT_FABRIC
Defines the properties for airbag materials.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EA Young’s Modulus, Longitudinal Direction
EB Young’s Modulus, Transverse Direction
EC Young’s Modulus, Normal Direction
PRBA, PRCA, PRCB Poisson’s Ratio in ba, ca, and cb directions
GAB, GBC, BCA Shear Moduli in ab., bc, and ca directions
Materials82
CSE Compressive Stress Elimination Option
0: Don’t Eliminate
1: Eliminate
EL Young’s Modulus for Elastic Liner
PRL Poisson’s Ratio for Elastic Liner
LRATIO Ratio of linear thickness to total fabric thickness
DAMP Rayleigh Damping Coefficient
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
FLC Fabric Leakage coefficient
FAC Fabric Area Coefficient
ELA Effective Leakage Area for blocked fabric
LNRC Liner Compression Flag
0: Off
1:On
Field Comments
83MaterialsMaterials
FORM Flag to modify Membrane Formulation for fabric material:
0: default
1: in variant Local Coordinate System
2: Green-Lagrange strain formulation
3: Large Strain with nonorthogonal material angles
4: Large Strainwith nonorthogonal material angles, and nonlinear material stress strain behavior. Define optional Load Curve Ids.
FVOPT Fabric Venting Option
1: Wang-Nefske formulas for venting, through orifice, with no blockage.
2: Wang-Nefske formulas for venting through orifice, with blockage.
3: Graefe, Krummheurer, and Siejak [1990] Leakage formulas with no blockage.
4: Graefe, Krummheurer, and Siejak [1990] Leakage formulas with blockage.
5: Leakage formulas based on flow through a porous media, with no blockage.
6: Leakage formulas based on flow through a porous media, with blockage.
TSRFAC Tensile Stress Cutoff Reduction factor
blank1, blank2, blank3 Blank Fields
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
LCA Load Curve Id for Stress vs. Strain along the a- axis
LCB Load Curve Id for Stress vs. Strain along the b- axis
LCAB Load Curve Id for Stress vs. Strain in the ab plane
LCUA Unload/Reload Curve Id for Stress vs. Strain along a- axis
LCUB Unload/Reload Curve Id for Stress vs. Strain along b- axis
LCUAB Unload/Reload Curve Id for Stress vs. Strain in the ab plane
LC_FLC Load Curve Id for Fabric Leakage Coefficient
Field Comments
Materials84
See Also:• LS-DYNA Keyword User’s Manual
MAT_PLASTIC_GREEN-NAGHDI_RATE
This model is available for brick elements only. It is similar to MAT_PLASTIC_KINEMATIC, but uses the Green-Naghdi Rate formulation for the stress update.
See Also:• LS-DYNA Keyword User’s Manual
LC_FAC Load Curve Id for Fabric Area Coefficient
LC_ELA Load Curve Id for Effective Leakage Area for blocked fabric
LC_TSR Load Curve Id for Tensile Stress Cutoff Reduction factor vs. Time
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Strength
ETAN Plastic Hardening Modulus
SRC Strain Rate Parameter
SRP Strain Rate Parameter
BETA Hardening Parameter
Field Comments
85MaterialsMaterials
MAT_3-PARAMETER_BARLAT
This material model is designed for modeling sheets with anisotropic materials under plane stress conditions.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
HR Hardening Rule
1: Linear
2: Exponential
3: Load Curve
P1, P2 Material Parameters
Materials86
See Also:• LS-DYNA Keyword User’s Manual
ITER Iteration Flag
0: Fully iterative
1: Fixed to 3 iterations
M Exponent in Barlat’s yield surface
R00, R45, R90 Lankford Parameters
LCID Load Curve Id for hardening rule
Epsilon_0 ε0 for determining initial yield stress for exponential hardening
SPI Parameter to redefine ε0
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
blank1, blank2, blank3 Blank Fields
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
Field Comments
87MaterialsMaterials
MAT_TRANS_ANISO_ELASPLASTIC
Simulates sheet forming processes with anisotropic material. Only transverse anisotropy can be considered.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Plastic Hardening Modulus
R Anisotropic Hardening Parameter
HLCID Load Curve Id for Effective Yield Stress vs. Effective Plastic Strain
Materials88
MAT_TRANS_ANISO_ELASPLASTIC_ECHANGE
Simulates sheet forming processes with anisotropic material. Only transverse anisotropy can be considered.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Plastic Hardening Modulus
R Anisotropic Hardening Parameter
HLCID Load Curve Id for Effective Yield Stress vs. Effective Plastic Strain
IDSCALE Load curve Id defining the scale factor for Young’s modulus change with respect to effective strain. Note: if EA, and COE are defined, this curve is not necessary.
EA, COE Coefficients (EA and ζ) defining Young’s modulus with respect to the effective strain. Note: if EA, and COE are defined, this curve is not necessary.
89MaterialsMaterials
MAT_BLATZ-KO_FOAM
Defines the properties for rubber like foams of polyurethane. It is a simple one parameter model with a fixed Poisson’s ratio of 0.25.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear Modulus
REF Use Reference Geometry to initialize stress tensor
Materials90
MAT_FLD_TRANSVERSELY_ANISOTROPIC
Simulates sheet forming processes with anisotropic material. Only transverse anisotropy can be considered.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Plastic Hardening Modulus
R Anisotropic Hardening Modulus
HLCID Load Curve Id defining Effective Yield Stress vs. Effective Plastic Strain
LCIDFLD Load Curve Id defining the Forming Limit Diagram (major vs. minor strain)
91MaterialsMaterials
MAT_NONLINEAR_ORTHOTROPIC
Defines an orthotropic nonlinear elastic material based on a finite strain formulation with initial geometry as the reference. Optional failure and stiffness properties are available.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EAA, EBB, ECC Young’s Modulus in the A, B and C directions
PRBA, PRCA, PRCB Poisson’s Ratio in the ba, ca and cb directions
GAB, GBC, GCA Shear Modulus in the ab, bc and ca directions
DT Temperature increment for stress stabilization
TRAMP Time to ramp up to the final temperature
ALPHA Thermal expansion coefficient
LCIDA, LCIDB, LCIDC Load Curve Id for nominal stress vs. nominal strain in the a- , b-, and c-axes
EFAIL Failure Strain
Materials92
See Also:• LS-DYNA Keyword User’s Manual
DTFAIL Timestep size criteria for element erosion
CDAMP Damping Coefficient
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
blank1, blank2, blank3 Blank Fields
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
LCIDAB, LCIDBC, LCIDCA
Load Curve Id for nominal shear stress vs. nominal shear strain in the ab, bc, and ca plane
Field Comments
93MaterialsMaterials
MAT_BAMMAN
Defines a material with temperature and rate dependent plasticity.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
T Initial Temperature
HC Heat Generation Coefficient
Ci Input parameters
Ai Initial value of state variable i
KAPPA Initial value of internal state variable 6 (κ)
Materials94
MAT_BAMMAN_DAMAGE
Defines a material with temperature and rate dependent plasticity including damage in the modeling.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
T Initial Temperature
HC Heat Generation Coefficient
Ci Input parameter
Ai Initial value of state variable i
N Exponent in damage evaluation
D0 Initial Damage (porosity)
FS Failure Strain for Erosion
95MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_CLOSED_CELL_FOAM
Defines a low density, closed polyurethane foam for simulating impact limiters in automotive applications.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
A, B, C Factors a, b, and c for Yield Stress definition
P0 Initial Foam Pressure
PHI Ratio of Foam to Polymer Density
GAMA0 Initial Volumetric Strain
LCID Load Curve Id defining vonMises Stress vs. Volumetric Strain
Materials96
MAT_ENHANCED_COMPOSITE_DAMAGE
Defines the properties of an orthrotropic material with optional brittle failure for composites. This is an enhanced version of MAT_COMPOSITE_DAMAGE (MAT_022).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EA Young’s Modulus, Longitudinal Direction
EB Young’s Modulus, Transverse Direction
EC Young’s Modulus, Normal Direction (NOT used)
PRBA, PRCA, PRCB Poisson’s Ratio in the ba, ca, and cb planes (PRCA, PRCB NOT used)
GAB, GBC, GCA Shear Modulus in the ab, bc, and ca planes
KF Bulk Modulus of failed material (NOT used)
97MaterialsMaterials
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
bl1, bl2, bl3 Blank Fields
Ai Components of Vector a, for AOPT=2
MANGLE Material Angle (Degrees), for AOPT=3
Vi Components of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
DFAILM Maximum Strain for matrix straining in tension/compression
DFAILS Maximum shear strain
TFAIL Timestep size criteria for element deletion
ALPH Shear Stress Parameter for NonLinear Term
SOFT Softening Reduction Factor
FBRT Softening of fiber Tensile Strength
YCFAC Reduction Factor for compressive fiber strength, after matrix failure
DFAILT Maximum Strain for fiber in tension
DFAILC Maximum Strain for fiber in compression
EFS Effective Failure Strain
XC Longitudinal Compression Strength
XT Longitudinal Tensile Strength
YC Transverse Compression Strength
YT Transverse Tensile Strength
SC Shear Strength, ab plane
Field Comments
Materials98
See Also:• LS-DYNA Keyword User’s Manual
CRIT Failure Criteria (Material Number)
54: Chang matrix failure criterion
55: Tsai-Wu matrix failure criterion
BETA Weight Factor for Shear term in tensile fiber mode
Field Comments
99MaterialsMaterials
MAT_LAMINATED_COMPOSITE_FABRIC
Defines a composite material with unidirectional layers, complete laminates and woven fabrics (for shell elements only).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EA Young’s Modulus, Longitudinal Direction
EB Young’s Modulus, Transverse Direction
EC Young’s Modulus, Normal Direction (NOT used)
PRBA Poisson’s Ratio in BA direction
Materials100
TAU1 Stress limit of first slightly nonlinear part of Shear Stress vs. Shear Strain curve
GAMMA1 Strain limit of first slightly nonlinear part of Shear Stress vs. Shear Strain curve
SLIMT1 Factor to determine the minimum Stress Limit after Stress Maximum (fiber Tension)
SLIMC1 Factor to determine the minimum Stress Limit after Stress Maximum (fiber Compression)
SLIMS Factor to determine the minimum Stress Limit after Stress Maximum (Shear)
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
TSIZE Time step size for Automatic Element Deletion
ERODS Maximum Element Strain for Element Layer Failure
SOFT Softening Reduction Factor in Crash front
FS Failure Surface Type
1: Smooth surface Failure with Quadratic criteria for both fiber and transverse directions
0: Smooth surface Failure with Quadratic criteria for transverse direction, with a limiting value in the fiber direction
-1: Faceted Failure surface
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
Field Comments
101MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
E11C Strain at Longitudinal Compression Strength, a-axis
E11T Strain at Longitudinal Tensile Strength, a-axis
E22C Strain at Transverse Compression Strength, b-axis
E22T Strain at Transverse Tensile Strength, b-axis
GMS Strain at Shear Strength, ab plane
XC Longitudinal Compression Strength
XT Longitudinal Tensile Strength
YC Transverse Compression Strength, b-axis
YT Transverse Tensile Strength, b-axis
SC Shear Strength, ab plane
Field Comments
Materials102
MAT_COMPOSITE_FAILURE_SHELL_MODEL
Defines the properties of a composite material with failure properties (for shell elements only).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EA Young’s Modulus, Longitudinal Direction
EB Young’s Modulus, Transverse Direction
EC Young’s Modulus, Normal Direction
PRBA, PRCA< PRCB Poisson’s Ratio in ba, ca and cb directions
GAB, GBC, GCA Shear Moduli in ab, bc and ca directions
KF Bulk Modulus of failed material
103MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
AOPT 0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
MAFLAG Material Axes Flag (NOT active for shells)
XP X-coordinate of point p for AOPT=1 and 4
YP Y-coordinate of point p for AOPT=1 and 4
ZP Z-coordinate of point p for AOPT=1and 4
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3, and 4
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
TSIZE Time step size for Automatic Element Deletion
ALP Nonlinear stress parameter
SOFT Softening Reduction Factor in Crashfront
FBRT Softening of fiber Tensile Strength
SR Reduction Factor
SF Softening Factor
XC Longitudinal Compression Strength
XT Longitudinal Tensile Strength
YC Transverse Compression Strength, b-axis
YT Transverse Tensile Strength, b-axis
SC Shear Strength, ab plane
Field Comments
Materials104
MAT_COMPOSITE_FAILURE_SOLID_MODEL
Defines the properties of a composite material with failure properties (for solid elements only).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EA Young’s Modulus, Longitudinal Direction
EB Young’s Modulus, Transverse Direction
EC Young’s Modulus, Normal Direction
PRBA, PRCA< PRCB Poisson’s Ratio in ba, ca and cb directions
GAB, GBC, GCA Shear Moduli in ab, bc and ca directions
KF Bulk Modulus of failed material
105MaterialsMaterials
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
4: Locally orthotropic in cylindrical coordinate system with the material axis determined by a vector v, and an originating point, P, which defines the centerline axis. This option is for solid elements only.
MAFLAG Material Axes Change Flag
1: Default
2: Switch Axes a and b
3: Switch Axes a and c
XP X-coordinate of point p for AOPT=1 and 4
YP Y-coordinate of point p for AOPT=1 and 4
ZP Z-coordinate of point p for AOPT=1and 4
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3, and 4
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
SBA In Plane Shear Strength
SCA Transverse Shear Strength
SCB Transverse Shear Strength
XXC Longitudinal Compression Strength, x-axis
YYC Transverse Compression Strength, b-axis
Field Comments
Materials106
See Also:• LS-DYNA Keyword User’s Manual
MAT_ELASTIC_WITH_VISCOSITY
Simulates the forming of glass products at high temperatures.
ZZC Normal Compression Strength, c-axis
XXT Longitudinal Tensile Strength, x-axis
YYT Transverse Tensile Strength, b-axis
ZZT Normal Tensile Strength, c-axis
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
Field Comments
107MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_ELASTIC_WITH_VISCOSITY_CURVE
Simulates the forming of glass products at high temperatures.Load curves are used to represent the temperature dependence of Poisson’s ratio, Young’s modulus, the coefficient of thermal expansion, and the viscosity.
RO Mass Density of the material
V0
A, B, C Viscosity coefficients
LCID Load Curve Id defining factor for viscosity vs. temperature
PRi
Ti Temperatures
Vi Corresponding Viscosity coefficients
Ei Corresponding Young’s moduli coefficients
ALPHAi Corresponding thermal expansion coefficients
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
V0
Field Comments
Materials108
See Also:• LS-DYNA Keyword User’s Manual
MAT_KELVIN-MAXWELL_VISCOELASTIC
A classic Kelvin-Maxwell material model for modeling viscoelastic bodies, like foams.
A, B, C Viscosity coefficients
LCID Load Curve Id defining factor for viscosity vs. temperature
PR_LC Load curve defining Poisson’s ratio as a function of temperature
YM_LC Load curve defining Young’s modulus as a function of temperature
A_LC Load curve defining the coefficient of thermal expansion as a function of temperature
V_LC Load curve defining the viscosity as a function of temperature
V_LOG Falg for the form of V_LC. If V_LOg =1, the value specified in V_LC is the natural logarithm of the viscosity. If V_LOg =0, the value is the viscosity.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
BULK Bulk Modulus (elastic)
GO Short time Shear Modulus
GI Long time Shear Modulus
DC Maxwell decay constant or Kelvin relaxation constant
Field Comments
109MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_VISCOUS_FOAM
A material to represent the Confor Foam on the ribs of EuroSID side impact dummy (valid only for solid elements under compressive load).
FO Formulation option
0: Maxwell
1: Kelvin
SO Strain output option
0: Maximum principal Strain occurring during the calculation
1: Maximum magnitude of principal Strain occurring during the calculation
2: Maximum Effective Strain occurring during the calculation
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E1 Initial Young’s Modulus
N1 Exponent in power law for Young’s Modulus
V2 Viscous Coefficient
E2 Elastic Modulus for viscosity
Field Comments
Materials110
See Also:• LS-DYNA Keyword User’s Manual
MAT_CRUSHABLE_FOAM
A material model for modeling crushable foam with optional damping and tension cutoff.
See Also:• LS-DYNA Keyword User’s Manual
N2 Exponent in power law for viscosity
PR Poisson’s Ratio
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
LCID Load Curve Id defining Yield Stress vs. Volumetric Strain
TSC Tensile Stress Cutoff
DAMP Rate sensitivity via damping coefficient
Field Comments
111MaterialsMaterials
MAT_RATE_SENSITIVE_POWERLAW_PLASTICITY
A strain rate sensitive elasto-plastic material model with a power law hardening.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
K Material Constant
M Strain Hardening Coefficient
N Strain Rate Sensitivity Coefficient
E0 Initial Strain Rate
VP Formulation for Rate Effects
0: Scale Yield Stress
1: ViscoPlastic Formulation
EPSO Factor to Normalize Strain (Time Units)
1: Seconds
1e-006 : Milliseconds
1e-006 : Microseconds
Materials112
See Also:• LS-DYNA Keyword User’s Manual
MAT_MODIFIED_ZERILLI_ARMSTRONG
A rate and temperature sensitive plasticity material model, sometimes used in ordinance design calculations.
LCID_K Load Curve Id defining material constant K vs. Effective Plastic Strain
LCID_M Load Curve Id defining material constant M vs. Effective Plastic Strain
LCID_N Load Curve Id defining material constant N vs. Effective Plastic Strain
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear Modulus
E0 Factor to normalize strain rate
N Exponent for bcc metal
TROOM Room Temperature
PC Pressure Cutoff
Field Comments
113MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
SPALL Spall Type
1: Minimum Pressure Limit
2: Maximum Principal Stress
3: Minimum Pressure Cutoff
Ci Coefficients for flow stress
EFAIL Failure Strain for Erosion
VP Formulation for Rate Effects
0: Scale Yield Stress
1: ViscoPlastic Formulation
Bi Coefficients for polynomial representation of temperature dependency of flow stress yield
Gi Coefficient for defining Heat Capacity and temperature dependency of Heat Capacity
BULK Bulk Modulus (for shell elements only)
Field Comments
Materials114
MAT_LINEAR_ELASTIC_DISCRETE_BEAM
A material model for linear elastic beams by using six springs each acting along one of its six degrees of freedom. The two nodes that define the beam can be coincident to give a zero length beam, or offset to give a finite length beam.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
TKR, TKS, TKT Translational Stiffness along local ar-, s-, and t- axes respectively
RKR, RKS, RKT Rotational Stiffness about local r-, s-, and t- axes respectively
TDR, TDS, TDT Translational viscous damping along local r-, s-, and t- axes respectively
RDR, RDS, RDT Rotational viscous damping about local r-, s-, and t- axes respectively
FOR, FOS, FOT Pre-load forces in r-, s- and t-directions repectively (optional)
MOR, MOS, MOT Pre-load moments in r-, s- and t-directions repectively (optional)
115MaterialsMaterials
MAT_NONLINEAR_ELASTIC_DISCRETE_BEAM
A material model for nonlinear elastic and nonlinear viscous beams by using six springs each acting along one of its six degrees of freedom. The two nodes that define the beam can be coincident to give a zero length beam, or offset to give a finite length beam.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
LCIDTR, LCIDTS, LCIDTT
Load Curve Id defining Translational Force along the r-, s-, and t- axes vs. Translational Displacement
LCIDRR, LCIDRS, LCIDRT
Load Curve Id defining Rotational Moment about the r-, s-, and t- axes vs. Rotational Displacement
LCIDTDR, LCIDTDS, LCIDTDT
Load Curve Id defining Translational Damping Force along the r-, s-, and t- axes vs. Translational Velocity
LCIDRDR, LCIDRDS, LCIDRDT
Load Curve Id defining Rotational Damping Force the r-, s-, and t- axes axis vs. Rotational Velocity
FOR, FOS, FOT Pre-load forces in r-, s- and t-directions repectively (optional)
MOR, MOS, MOT Pre-load moments in r-, s- and t-directions repectively (optional)
Materials116
MAT_NONLINEAR_PLASTIC_DISCRETE_BEAM
A a material model for nonlinear elastoplastic, linear viscous behavior of beams by using six springs each acting along one of its six degrees of freedom. The two nodes that define the beam can be coincident to give a zero length beam, or offset to give a finite length beam.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
TKR, TKS, TKT Translational Stiffness along local r-, s-, and t- axes respectively
RKR, RKS, RKT Rotational Stiffness about local r-, s-, and t- axes respectively
TDR, TDS, TDT Translational viscous damping along local r-, s-, and t- axes respectively
RDR, RDS, RDT Rotational viscous damping about local r-, s-, and t- axes respectively
LCPDR, LCPDS, LCPDT
Load Curve Id for Yield Force vs. Plastic Displacement along local r-, s-, and t- axes respectively
LCPMR, LCPMS, LCPMT
Load Curve Id for Yield Moment vs. Plastic Rotation about local r-, s-, and t- axes respectively
117MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_SID_DAMPER_DISCRETE_BEAM
A material model for side impact dummy, using a damper that is not adequately taken care of by the nonlinear force versus relative velocity curves.
FFAILR, FAILS, FAILT Failure Parameters corresponding to Force Fr, Fs, Ft
MFAILR, MFAILS, MFAILT
Failure Parameters corresponding to Moment Mr, Ms, Mt
UFAILR, UFAILS, UFAILT
Failure Parameters corresponding to Displacement Ur, Us, Ut
TFAILR, TFAILS, TFAILT
Failure Parameters corresponding to Rotation θr, θs, θt
FOR, FOS, FOT Pre-load forces in r-, s- and t-directions repectively (optional)
MOR, MOS, MOT Pre-load moments in r-, s- and t-directions repectively (optional)
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
Field Comments
Materials118
See Also:• LS-DYNA Keyword User’s Manual
RO Mass Density of the material
ST Piston Stroke
D Piston Diameter
R Orifice Radius
H Orifice Controller Position
K Damping Constant
C Discharge Coefficient
C3 Coefficient for fluid inertia term
STF Stiffness Coefficient (piston bottom out)
RHOF Fluid Density
C1 Coefficient of linear velocity term
C2 Coefficient of quadratic velocity term
LCIDF Load Curve Id defining Force vs. Piston Displacement
LCIDD Load Curve Id defining Damping Coefficient vs. Piston Displacement
S0 Initial Displacement
NUM_RFS Number of Orifice Location
ORFLOCi Orifice Location of the i-th orifice, relative to the fix end
ORFRADi Orifice Radius of the i-th orifice
SFi Scale factor on calculated force for the i-th orifice
DCi Linear viscous damping coefficient (after damper bottoms out in tension or compression) for the i-th orifice
Field Comments
119MaterialsMaterials
MAT_HYDRAULIC_GAS_DAMPER_DISCRETE_BEAM
A special element that represents a combined hydraulic and gas-filled damper with a variable orifice coefficient. This material can only be used as a discrete beam element.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
C0 Length of Gas Column
N Adiabatic constant
P0 Initial gas Pressure
PA Atmospheric Pressure
AP Piston Cross-Section Area
KH Hydraulic Constant
LCID Load Curve Id Defining Orifice Area vs. Element Deletion
FR Return factor on orifice force
SCLF Scale factor on Force
CLEAR Clearance
Materials120
MAT_CONCRETE_DAMAGE
A material model for analyzing buried steel reinforced concrete structure with impulsive loading.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGF Maximum principal Stress at Failure
A0, A0Y Cohesion and Cohesion for Yield
121MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
A1, A2 Pressure Hardening Coefficients
A1Y, A2Y Pressure Hardening Coefficients for yield limit
A1F, A2F Pressure Hardening Coefficients Failed Material)
B1 Damage Scaling Factor
B2 Damage Scaling Facto for uniaxial tensile path
B3 Damage Scaling Facto for triaxial tensile path
PER Percent Reinforcement
ER Young’s Modulus for Reinforcement
PRR Poisson’s Ration for Reinforcement
SIGY Initial Yield Stress
ETAN Tangent Modulus/Plastic hardening Modulus
LCP Load Curve Id giving rate sensitivity for principal material
LCR Load Curve Id giving rate sensitivity for reinforcement
LAMBDAi Tabulated Damage functions
ETAi Tabulated Scale Factors
Field Comments
Materials122
MAT_LOW_DENSITY_VISCOUS_FOAM
A material model for low density urethane foam with high compressibility, and with rate sensitivity characterized by a relaxation curve.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
LCID Load Curve Id for nominal Stress vs. Strain
TC Tension Cutoff Stress
HU Hysteretic Unloading Factor between 0 to 1
BETA Decay constant to model creep in unloading
DAMP Viscous coefficient
SHAPE Shape factor for unloading
FAIL Failure Option after Cutoff Stress
1: Tensile stress remains at cutoff value
2: Tensile stress is reset to zero
123MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_ELASTIC_SPRING_DISCRETE_BEAM
A model for elastic springs with damping to be combined and represented with a discrete beam element.
BVFLAG Bulk Viscosity activation Flag
0: No
1: Active
KCON Stiffness coefficient for contact interface stiffness
LCID2 Load Curve Id of relaxation curve
BSTART Fit Parameter
TRAMP Optional ramp time for loading
NV Number of terms in fit
NUM_RFS Number of viscoelastic constants
GI1 Optional relaxation modulus for rate effect
BETAI1 Optional decay constant
REF Use Reference Geometry to initialize stress tensor
0: Off
1: On
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
Field Comments
Materials124
See Also:• LS-DYNA Keyword User’s Manual
MAT_BILKHU/DUBOIS_FOAM
A material model to simulate isotropic crushable foams using uniaxial and triaxial test data.
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
K Elastic loading and unloading stiffness
F0 Optional initial force
D Optional viscous damping coefficient
CDF Compressive displacement at failure
TDF Tensile displacement at failure
FLCID Load Curve Id defining Yield Force vs. Deflection for nonlinear behavior
HLCID Load Curve Id defining Force vs. Relative Velocity for nonlinear behavior
Ci Damping Coefficients
DLE Scale factor for time unit
GLCID Load Curve Id defining Scale Factor vs. Deflection for Load Curve Id (HLCID)
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
Field Comments
125MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
YM Young’s Modulus
LCPY Load Curve Id defining Yield Pressure vs. Volumetric Strain
LCUYS Load Curve Id defining uniaxial Yield Stress vs. Volumetric Strain
VC Viscous Damping Coefficient
PC Pressure Cutoff
VPC Variable Pressure Cutoff as a fraction of pressure yield value
TC Tension Cutoff for uniaxial tensile stress
VTC Variable Tension Cutoff as a fraction of uniaxial compressive yield strength
LCRATE Load Curve Id defining Scale Factor for the previous yield curves, dependent upon the volumetric strain vs. Volumetric plastic Strain
PR Poisson coefficient applying to both elastic and plastic deformations
KCON Stiffness coefficient for contact interface stiffness. If undefined, one third of Young’s Modulus (YM) is used..
ISFLG Tensile response flag (active only if negative abscissa are present in the load curve LCUYS).
.EQ. 0: load curve abscissa in tensile region correspond to volumetric strain.
.EQ. 1: load curve abscissa in tensile region correspond to effective strain.
Field Comments
Materials126
MAT_GENERAL_VISCOELASTIC
A general viscoelastic Maxwell model used for modeling dense continuum rubber and solid explosives.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
BULK Elastic Bulk Modulus
PCF Tensile Pressure elimination flag (for solid elements only)
1: yes (Tensile Pressure reset to zero)
0: no (Tensile Pressure NOT reset to zero)
EF Elastic Flag
1: Elastic layer
0: Viscoelastic layer
LCID Load Curve Id for deviatoric behavior
NT Number of terms in shear fit
BSTART Parameter for resetting the exponents in the Relaxation Curve
TRAMP Optional Time ramp for loading
LCIDK Load Curve ID defining the bulk behavior
127MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_HYPERELASTIC_RUBBER
A general hyperelastic rubber material model, combined optionally with linear viscoelasticity.
NTK Number of terms in bulk
BSTARTK Fit Parameter for bulk
TRAMPK Optional ramp time for bulk loading
NUM_RFS number of viscoelastic constants
GIi Optional shear relaxation modulus for the i-th term
BETAIi Optional shear Decay Constant for the i-th term
KIi Optional bulk Relaxation Modulus for the i-th term
BETAKIi Optional bulk Decay Constant for the i-th term
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
Field Comments
Materials128
See Also:• LS-DYNA Keyword User’s Manual
MID Material identification number (Integer > 0)
RO Mass Density of the material
PR Poisson’s Ratio
N Constants to solve for
1: Solve for C10, C01
2: Solve for C10, C01, C11, C20, C02
3: Solve for All constants (C10, C01, C11, C20, C02, and C30)
NV Number of Prony series terms in fit
G Shear Modulus
SIGF Limit stress for frequency independent, frictional, Damping
SGL Specimen gauge length
SW Specimen Width
ST Specimen Thickness
LCID1 Load Curve Id defining Force vs. Actual Change in gauge Length
DATA Type of experimental data
0:Uniaxial
LCID2 Load Curve Id of relaxation curve
BSTART Fit Parameter
TRAMP Optional ramp time for loading
Ci Material Constants
NUM_RFS Number of viscoelastic constants
GIi Optional Shear Relaxation Modulus for the i-th term
BETAIi Optional Decay Constants for the i-th term
Field Comments
129MaterialsMaterials
MAT_OGDEN_RUBBER
An Ogden rubber material model, combined optionally with linear viscoelasticity.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
PR Poisson’s Ratio
N Order to fit the Ogden model
NV Number of Prony series terms in fit
G Shear Modulus
SIGF Limit stress for frequency independent, frictional, Damping
SGL Specimen gauge length
SW Specimen Width
ST Specimen Thickness
Materials130
See Also:• LS-DYNA Keyword User’s Manual
MAT_SOIL_CONCRETE
An efficient soil and concrete material model.
LCID1 Load Curve Id defining Force vs. Actual Change in Length
DATA Type of experimental data
1:Uniaxial
2:Biaxial
LCID2 Load Curve Id of relaxation curve
BSTART Fit Parameter
TRAMP Optional ramp time for loading
MUi i-th Shear Modulus
ALPHAi i-th Exponent
NUM_RFS Number of viscoelastic constants
GIi i-th Optional Shear Relaxation Modulus
BETAIi i-th Optional Decay Constant
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear Modulus
Field Comments
131MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
K Bulk Modulus
LCPV Load Curve Id defining Pressure vs. Volumetric Strain
LCYP Load Curve Id defining von Mises Stress vs. Pressure
LCFP Load Curve Id defining Plastic Strain at which fracture starts vs. Pressure
LCRP Load Curve Id defining Plastic Strain at which residual strength is released vs. Pressure
PC Pressure Cutoff
OUT Output option for plastic strain
0: Volumetric
1: Deviatoric
B Residual strength factor after cracking
FAIL Failure flag
0: No
1: Element Erodes when Pressure reached failure pressure
2: No tension in element when Pressure reached failure pressure
Field Comments
Materials132
MAT_HYSTERETIC_SOIL
A nested surface material model with five superimposed layers of elasto-perfectly plastic material, each with its own elastic moduli and yield values.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
K0 Bulk Modulus
P0 Pressure Cutoff
B Exponent for pressure sensitive moduli
A0, A1, A2 Yield Function Constants
DF Damping Factor
RP Reference Pressure
LCID Load Curve Id defining Shear Stress vs. Shear Strain
SCLF Scale Factor o apply on shear stress in LCID
DIL_A Dilation Parameter A
DIL_B Dilation Parameter B
DIL_C Dilation Parameter C
DIL_D Dilation Parameter D
133MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_RAMBERG_OSGOOD
A simple material model of shear behavior, and can be used for seismic analysis.
GAMi Shear Strains (if LCID is zero)
PINIT Pressure sensitivity flag:
.EQ. 0: Use current pressure
.EQ. 1: Use pressure from initial stress state
.EQ. 2: Use initial “plane stress”pressure
.EQ. 3: Use compressive initial vertical stress
TAUi Shear Stresses (if LCID is zero)
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
GAMY Reference Shear Strain
TAUY Reference Shear Stress
ALPHA Stress coefficient
R Stress exponent
BULK Elastic Bulk Modulus
Field Comments
Materials134
See Also:• LS-DYNA Keyword User’s Manual
MAT_PLASTICITY_WITH_DAMAGE
An elasto-visco-plastic material with an arbitrary stress versus strain curve and arbitrary strain rate dependency. Damage, in this model, is considered before rupture occurs.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Tangent Modulus
EPPF Plastic Strain, at which material softening begins
TDEL Minimum time step size for Automatic Element Deletion
C, P Strain Rate Parameters
LCSS Load Curve Id defining Effective Stress vs. Effective Plastic Strain
LCSR Load Curve Id defining Strain Rate Scaling Effect on Yield Stress
EPPFR Plastic Strain at which material ruptures
VP Formulation for Rate Effects
0: Scale Yield Stress
1: Viscoplastic Formulation
135MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_PLASTICITY_WITH DAMAGE_ORTHO_RCDC
An elasto-visco-plastic material with an arbitrary stress versus strain curve and arbitrary strain rate dependency. This includes an orthotropic damage model (only for shell elements).
LCDM Load Curve Id defining nonlinear damage curve
NUMINT No. of through thickness integration points which must fail before the element is deleted
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Tangent Modulus
EPPF Plastic Strain, at which material softening begins
TDEL Minimum time step size for Automatic Element Deletion
Field Comments
Materials136
See Also:• LS-DYNA Keyword User’s Manual
C, P Strain Rate Parameter
LCSS Load Curve Id defining Effective Stress vs. Effective Plastic Strain
LCSR Load Curve Id defining Strain Rate Scaling Effect on Yield Stress
EPPFR Plastic Strain at which material ruptures
VP Formulation for Rate Effects
0: Scale Yield Stress
1: Viscoplastic Formulation
NUMINT No. of through thickness integration points which must fail before the element is deleted
LCDM Load Curve Id defining nonlinear damage curve
ALPHA Parameter αBETA Parameter βGAMMA Parameter γD0 Parameter D0
B Parameter b
LAMDA Parameter λDS Parameter Ds
L Optional characteristic element length for this material.
Field Comments
137MaterialsMaterials
MAT_FU_CHANG_FOAM
A material such as low and medium density foams, for hysteric unloading behaviors. Rate effects can be included in this material model.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
ED Young’s Relaxation Modulus for rate effect
TC Tension Cutoff Stress
FAIL Failure option after Cutoff Stress is reached
0: Tensile Stress Remains at cutoff
1: Tensile Stress Resets to Zero
DAMP Viscous Coefficient
TBID Table Id for nominal Stress vs. Strain
Materials138
BVFLAG Bulk Viscosity activation Flag
0: No
1: Active
SFLAG Strain Rate Flag
0: True strain
1: Engineering strain
RFLAG Strain Rate evaluation flag
0 : First principal direction
1 : Principal strain rates for each principal direction
2: Volumetric strain rate
TFLAG Tensile Stress Evaluation Flag
0: Linear
1: Input via Load Curves with the tensile response corresponding to negative values of stress and strain
PVID Load Curve Id defining Pressure vs. Volumetric Strain
SRAF Strain Rate averaging flag
0: Weighted running average
1: Average of the last twelve values
REF User reference geometry to initialize the stress tensor.:
.EQ. 0: OFF
.EQ. 1: ON
HU Hysteric unloading factor between 0 and 1 (default = 1, i.e. no energy dissipation).
D0, N0, C0, Ni, Ci Material Constants
AIJ, SIJ Material Constants
MINR Minimum strain rate of interest
MAXR Maximum strain rate of interest
SHAPE Shape factor for unloading. Active for nonzero values of the hysteric unloading factor HU.
Field Comments
139MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_WINFRITH_CONCRETE
A smeared crack, smeared rebar, material model (only for the 8-noded single integration point continuum element).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
TM Tangent Modulus of Concrete
PR Poisson’s Ratio
UCS Uniaxial Compression Strength
UTS Uniaxial Tensile Strength
FE Depends on value for RATE
If RATE = 0, FE is Fracture Energy per unit area in opening crack
If RATE = 1, FE is crack width at which crack-normal tensile stress becomes zero
ASIZE Aggregate size (radius)
E Young’s Modulus for rebar
YS Yield Stress for rebar
Materials140
See Also:• LS-DYNA Keyword User’s Manual
EH Hardening Modulus for rebar
UELONG Ultimate elongation before rebar fails
RATE Rate effects Flag
0: Included (MAT_0 84)
1: Turned off (MAT_0 85)
CONM Factor to convert model mass units to kg
CONL Factor to convert model length units to meters (if CONM .GT. 0)
CONT Factor to convert model time units to seconds
LCID Defining Pressure vs. Volumetric Strain
Field Comments
141MaterialsMaterials
MAT_WINFRITH_CONCRETE_REINFORCEMENT
A rebar reinforcement material model (material type 84). Reinforcement quantity is defined as the ratio of the cross-sectional area of steel, relative to the cross-sectioanl area of concrete in the element (or layer).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
TM Tangent Modulus of Concrete
PR Poisson’s Ratio
UCS Uniaxial Compression Strength
UTS Uniaxial Tensile Strength
FE Depends on value for RATE
If RATE = 0, FE is Fracture Energy per unit area in opening crack
If RATE = 1, FE is crack width at which crack-normal tensile stress becomes zero
Materials142
ASIZE Aggregate size (radius)
E Young’s Modulus for rebar
YS Yield Stress for rebar
EH Hardening Modulus for rebar
UELONG Ultimate elongation before rebar fails
RATE Rate effects Flag
0: Included (MAT_0 84)
1: Turned off (MAT_0 85)
CONM Factor to convert model mass units to kg
CONL Factor to convert model length units to meters (if CONM .GT. 0)
CONT Factor to convert model time units to seconds
LCID Defining Pressure vs. Volumetric Strain
EID1 First element Id in group
EID2 Last element Id in group
INC Element increment for genaration
XR X-reinforcement quantity (for bars running parallel to global x-axis)
YR Y-reinforcement quantity (for bars running parallel to global y-axis)
ZR Z-reinforcement quantity (for bars running parallel to global z-axis)
PID Part Id of reinforced elements
AXIS Axis normal to layer:
.EQ. 1: A and B are parallel to global Y and Z, respectively
.EQ. 2 A and B are parallel to global X and Z, respectively
.EQ. 3: A and B are parallel to global X and Y, respectively
COOR Coordinate location of layer (X-coordinate if AXIS = 1, Y-Coordinate if AXIS = 2, Z-Coordinate if AXIS = 3)
RQA Reinforcement quantity (A)
RQB Reinforcement quantity (B)
Field Comments
143MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_ORTHOTROPIC_VISCOELASTIC
A viscoelastic material model (only for shell elements).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EA Young’s Modulus in Longitudinal Direction
EB Young’s Modulus in Transverse Direction
EC Young’s Modulus in Normal Direction
VF Volume fraction for viscoelastic material
K Elastic Bulk Modulus
G0 Short time Shear Modulus
GINF Long time Shear Modulus
BETA Decay Constant
Materials144
See Also:• LS-DYNA Keyword User’s Manual
PRBA, PRCA, PRCB Poisson’s Ratio in the ba, ca and cb directions
GAB, GBC, GCA Shear Moduli in the ab, bc and ca directions
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
MANGLE Material Angle (Degrees), for AOPT=3
blank1, blank2, blank3 Blank Fields
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
Field Comments
145MaterialsMaterials
MAT_CELLULAR_RUBBER
A material model for a cellular rubber with confined air pressure, combined with linear viscoelasticity.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
PR Poisson’s Ratio
N Order or fit
SGL Specimen Gauge Length
SW Specimen Width
ST Specimen Thickness
LCID Load Curve Id defining the Force vs. Actual Change in gauge Length
C10, C01, C11, C20, C02
Material Constants
P0 Initial Air Pressure
PHI Ratio of cellular rubber to rubber density
IVS Initial Volumetric Strain
G Optional shear relaxation modulus, G, for rate effects
BETA Optional Decay Constant
Materials146
See Also:• LS-DYNA Keyword User’s Manual
MAT_MTS
This MTS material model, developed by Maudlin, Davidson, and Henninger [1990], is used for applications involving high pressures, large strains, and high strain rates. This model uses dislocation mechanics and provides an understanding of the plastic deformation process in ductile materials.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
SIGA Dislocation interaction with long-range barriers
SIGI Dislocation interaction with interstitial atoms
SIGS Dislocation interaction with solute atoms
SIG0 NOT used
BULK Bulk Modulus (for shell elements)
HF0, HF1, HF2 Dislocation generation material constants
SIGSO Saturation Threshold stress at 0 degrees K
147MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_PLASTICITY_POLYMER
An elasto-plastic material model with arbitrary stress versus strain curve, and arbitrary strain rate dependency.
EDOTSO, EDOTO, EDOTI, EDOTS
Reference Strain rates
BURG Magnitude of Burgers vector
CAPA Material Constant, A
BOLTZ Boltzmann’s constant, k
SM0, SM1, SM2 Shear Modulus Constants
G0, GOI, GOS Normalized activation energies
PINV, QINV, PINVI, QINVI, PINVS., QINVS., ALPHA
Material Constants
RHOCPR Product of density and specific heat
TEMPRF Initial Element Temperature
EPSO Factor to normalize strain rate
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
Field Comments
Materials148
See Also:• LS-DYNA Keyword User’s Manual
MAT_ACOUSTIC
Defines the properties of materials used to track low pressure waves in acoustic media, like air or water (only for acoustic pressure elements).
MID Material identification number (Integer > 0)
RO Mass Density of the material
PR Poisson’s Ratio
C, P Strain Rate Parameters
LCSS Load Curve Id defining Effective Stress vs. Total Effective Strain
LCSR Load Curve Id defining Strain Rate Scaling effect on Yield Stress
EFTX Failure Flag
0: Failure determined by Maximum tensile strain
1: Failure determined only by tensile strain in local x direction
2: Failure determined only by tensile strain in local y direction
DAMP Stiffness proportional damping ratio
RATEFAC Filtering factor for strain rate effect
LCFAIL Load Curve Id defining variation of Failure strain with Strain rate
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
Field Comments
149MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MID Material identification number (Integer > 0)
RO Mass Density of the material
C Sound Speed
BETA Damping Factor
CF Cavitation Flag
0: Off
1: On
ATMOS Atmospheric Pressure
GRAV Gravitational Acceleration constant
XP, YP, ZP Coordinates of free surface point
XN, YN, ZN Direction cosines of free surface normal vector
Field Comments
Materials150
MAT_SOFT_TISSUE
Defines a transversely isotropic hyperelastic material that represents biological soft tissue such as ligaments, tendons, and fascia.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
Ci Hyperelastic Coefficients
XK Bulk Modulus
XLAM Stretch ratio at which fibers are straightened
FANG Fiber angle in local shell coordinate system (shell elements only)
XLAMO Initial fiber stretch
FAILSF stretch ratio for ligament fibers at failure (shell elements only). If zero, failure is not considered.
FAILSM stretch ratio for surrounding matrix material at failure (shell elements only). If zero, failure is not considered.
151MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
FAILSHR Shear strain at failure of a material point (shell elements only). If zero, failure is not considered. This failure value is independent of FAILSF and FAILSM.
AOPT 0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
AX, AY, AZ Components of first material axis point/vector
BX, BY, BZ Components of second material axis point/vector
LAX, LAY, LAZ Component of fiber orientation vector (Brick elements only)
MACF Material axes change flag for brick element:
=1 No Change; = 2 switch mateial axes a and b
=3 switch material axes a and c ; =4 switch material axes b and c
Field Comments
Materials152
MAT_SOFT_TISSUE_VISCO
A transversely isotropic hyperelastic material model that represents biological soft tissue such as ligaments, tendons, and fascia. This model has a viscoelastic option activating a six-term Prony series kernel for the relaxation function.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
Ci Hyperelastic Coefficients
XK Bulk Modulus
XLAM Stretch ratio at which fibers are straightened
FANG Fiber angle in local shell coordinate system (shell elements only)
XLAMO Initial fiber stretch
153MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_ELASTIC_6DOF_SPRING_DISCRETE_BEAM
A material model for simulating the effects of nonlinear elastic and nonlinear viscous beams using six springs each acting along one of it six degrees-of-freedom.
AOPT 0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
AX, AY, AZ Components of first material axis point/vector
BX, BY, BZ Components of second material axis point/vector
LAX, LAY, LAZ Component of fiber orientation vector (Brick elements only)
Si Spectral strengths for prony series relaxation kernel
Ti Characteristic time for prony series relaxation kernel
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
TPIDR Part Id governing the Translational motion in the local r direction (If zero, no force is computed in this direction)
Field Comments
Materials154
See Also:• LS-DYNA Keyword User’s Manual
MAT_INELASTIC_SPRING_DISCRETE_BEAM
A material model for elastoplastic springs, with damping to be represented with discrete beam elements. A yield force versus deflection is used which can vary in tension and compression.
TPIDS Part Id governing the Translational motion in the local s direction (If zero, no force is computed in this direction)
TPIDT Part Id governing the Translational motion in the local t direction (If zero, no force is computed in this direction)
RPIDR Part Id governing the Rotational motion about the local r direction (If zero, no moment is computed in this direction)
RPIDS Part Id governing the Rotational motion about the local s direction (If zero, no moment is computed in this direction)
RPIDT Part Id governing the Rotational motion about the local t direction (If zero, no moment is computed in this direction)
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
K Elastic Loading/Unloading Stiffness
F0 Optional initial force
D Optional viscous damping coefficient
Field Comments
155MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_INELASTIC_6DOF_SPRING_DISCRETE_BEAM
A material model for nonlinear inelastic and nonlinear viscous beams using six springs each acting along one of it six degrees-of-freedom.
CDF Compressive displacement at failure
TDF Tensile Displacement at failure
FLCID Load Curve Id defining Yield Force vs. Plastic Displacement
HLCID Load Curve Id defining Force vs. Relative Velocity
C1, C2 Damping Coefficients
DLE Scale Factor for time unit
GLCID Load Curve Id defining a Scale Factor vs. Deflection for Load Curve Id, HLCID
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
TPIDR Part Id governing the Translational motion in the local r direction (If zero, no force is computed in this direction)
TPIDS Part Id governing the Translational motion in the local s direction (If zero, no force is computed in this direction)
TPIDT Part Id governing the Translational motion in the local t direction (If zero, no force is computed in this direction)
Field Comments
Materials156
See Also:• LS-DYNA Keyword User’s Manual
MAT_BRITTLE_DAMAGE
A material model with anisotropic brittle damage characteristics, used mainly for concrete but can be applied for a variety of brittle materials.
RPIDR Part Id governing the Rotational motion about the local r direction (If zero, no moment is computed in this direction)
RPIDS Part Id governing the Rotational motion about the local s direction (If zero, no moment is computed in this direction)
RPIDT Part Id governing the Rotational motion about the local t direction (If zero, no moment is computed in this direction)
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
TLIMIT Tensile Limit
SLIMIT Shear Limit
FTOUGH Fracture Toughness
SRETEN Shear Retention
VISC Viscosity
Field Comments
157MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_GENERAL_JOINT_DISCRETE_BEAM
Defines the properties of a general joint constraining any combination of degrees of freedom between two nodes.
FRA_RF Fraction of reinforcement in section
E_RF Young’s Modulus of Reinforcement
YS_RF Yield Stress of Reinforcement
EH_RF Hardening Modulus of Reinforcement
FS_RF Failure Strain of Reinforcement
SIGY Compressive Yield Stress
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
TR Translational Constraint Code along r-axis
0: Free
1:Fixed
Field Comments
Materials158
See Also:• LS-DYNA Keyword User’s Manual
TS Translational Constraint Code along s-axis
0: Free
1:Fixed
TT Translational Constraint Code along t-axis
0: Free
1:Fixed
RR Rotational Constraint Code about r-axis
0: Free
1:Fixed
RS Rotational Constraint Code about s-axis
0: Free
1:Fixed
RT Rotational Constraint Code about t-axis
0: Free
1:Fixed
RPST Penalty stiffness scale factor for translational constraints
RPSR Penalty stiffness scale factor for rotational constraints
Field Comments
159MaterialsMaterials
MAT_SIMPLIFIED_JOHNSON_COOK
A material model used for problems where the strain rates vary over a large range. In this model, thermal effect and damage are ignored and maximum stress is directly limited since thermal softening is not available.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
VP Formulation for Rate Effects
0: Scale Yield Stress
1: Viscoplastic Formulation
A, B, N, C Parameters used in the Johnson-Cook flow stress equation
PSFAIL Effective Plastic Strain at Failure
SIGMAX Maximum Stress obtained from Work Hardening before rate effects are added
SIGSAT Saturation Stress
EPSO Effective Plastic Strain rate
Materials160
MAT_SIMPLIFIED_JOHNSON_COOK_ORTHO_DAMAGE
Defines the properties of a material used for problems where the strain rates vary over a large range. Orthotropic damage is included as a means for treating failure in aluminum panels (only for shell elements with multiple through thickness integration points).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
VP Formulation for Rate Effects
0: Scale Yield Stress
1: Viscoplastic Formulation
EPPFR Plastic Strain at which the material ruptures
LCDM Load Curve Id defining nonlinear damage curve
NUMINT No. of through thickness integration points which must fail before element is deleted
A, B, N, C Parameters used in the Johnson-Cook flow stress equation
PSFAIL Effective Plastic Strain at Failure
SIGMAX Maximum Stress obtained from Work Hardening before rate effects are added
SIGSAT Saturation Stress
EPSO Effective Plastic Strain rate
161MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_SPOTWELD
A material model for spotweld modeled with beam element type 9, and solid element type 1.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Initial Yield Stress
ET Hardening Modulus
DT Time Step Size for Mass Scaling
TFAIL Failure Time (Ignored if value is zero)
EFAIL Effective Plastic Strain at Failure
NRR Axial force resultant NrrF (or Maximum Axial Stress σrrF) at failure
NRS Force resultant NrsF (or Maximum Shear Stress τF) at failure
NRT Force resultant NrtF at failure
MRR Torsional moment resultant MrrF at failure
MSS Moment resultant MssF at failure
MTT Moment resultant MttF at failure
NF No. of force vectors stored for filtering
Materials162
See Also:• LS-DYNA Keyword User’s Manual
MAT_SPOTWELD_DAMAGE-FAILURE
A material model used in spotweld, modeled with beam element type 9, and solid element type 1. Damage parameters are also included in this model.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Initial Yield Stress
ET Hardening Modulus
DT Time Step Size for Mass Scaling
TFAIL Failure Time (Ignored if value is zero)
EFAIL Effective Plastic Strain at Failure
NRR Axial force resultant NrrF (or Maximum Axial Stress σrrF) at failure
NRS Force resultant NrsF (or Maximum Shear Stress τF) at failure
NRT Force resultant NrtF at failure
MRR Torsional moment resultant MrrF at failure
163MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_SPOTWELD_DAIMLERCHRYSLER
A material model used in spotweld, modeled with solid element type 1, with type 6 hour glass control. Special Damage parameters are used in this model.
MSS Moment resultant MssF at failure
MTT Moment resultant MttF at failure
NF No. of force vectors stored for filtering
RS Rupture Strain
OPT Failure Option
0: Resultant based failure
1: Stress based failure computed from resultant (Toyota)
2: User subroutine to determine failure
3: Notch stress based failure (beam weld only)
4: Stress intensity factor at failure (beam weld only)
5: Structural stress at failure (beam weld only)
FVAL Failure parameter:
.EQ. 3: Notch stress value at failure (σKF)
.EQ. 4: Stress intensity factor value at failure (KeqF)
.EQ. 5: Structural stress value at failure (σSF)
.EQ. 6: Number of cycles that that failure condition must be met to trigger beam deletion.
.EQ. 9: Number of cycles that that failure condition must be met to trigger beam deletion.
Note: Values of -2, -1, 0, 1, 2, 7 - Not used
TRUE_T True weld thickness. This optional value is available for solid element failure by OPT = 0, 1, 7, or -2.
BETA Damage model decay rate.
Field Comments
Materials164
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
DT Time Step Size for Mass Scaling
TFAIL Failure Time (Ignored if value is zero)
EFAIL Effective Plastic Strain at Failure
NF Number of failure function evaluations stored for filtering by time averaging.
RS Rupture Strain
TRUE_T True weld thickness for hexahedron solid weld element.
CON_ID Connection Id of *DEFINE_CONNECTION
165MaterialsMaterials
MAT_GEPLASTIC_SRATE_2000a
Defines properties for the General Electric’s commercially available thermoplastics subjected to high strain rates. This model features variation of yield stress dependent upon strain rate, cavitation effects of rubber modified material, and automatic element deletion for either ductile or brittle materials.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
RATESF Constant in plastic strain rate equation
EDOTO Reference Strain Rate
ALPHA Pressure Sensitive Factor
LCSS Load Curve Id (or Table Id) for post Yield Stress behavior vs. Strain
LCFEPS Load Curve Id for Plastic failure Strain vs. Strain Rate
LCFSIG Load Curve Id for Maximum principal failure Stress vs. Strain Rate
LCE Load Curve Id for Unloading Moduli vs. Plastic Strain
Materials166
MAT_HYPERBOLIC_SIN
Defines properties for modeling materials with temperature and rate dependent plasticity.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
T Initial Temperature
HC Heat Generation Coefficient
VP Formulation for Rate Effects
0: Scale Yield Stress
1: Viscoplastic Formulation
ALPHA, N, A, Q, G Material constitutive constants
EPSO Effective plastic strain rate
167MaterialsMaterials
MAT_ANISOTROPIC_VISCOPLASTIC
Defines an anisotropic viscoplastic material that is applied to either shell or brick elements. The material constants may be input directly, or by stress-strain data. If stress-strain data is provided, a least squares fit will be performed to determine the constants.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Initial Yield Stress
FLAG Flag for material parameters
LCSS Load Curve Id for Effective Stress vs. Effective Plastic Strain
Materials168
ALPHA α distribution hardening:
=0: Kinematic hardening
= 1: Isotropic hardening
QRi, CRi Isotropic Hardening Parameters
QXi, CXi Kinematic Hardening Parameters
VK, VM Viscous Material Parameters
R00/F R00 for shell, or F for solid
R45/G R45 for shell, or G for solid
R90/H R90 for shell, or H for solid
L, M, N Parameters (for solid elements only
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
4: Locally orthotropic in cylindrical coordinate system with the material axis determined by a vector v, and an originating point, P, which defines the centerline axis. This option is for solid elements only.
FAIL Failure flag:
.LT. 0: user defined failure subroutine to determine failure.
.EQ. 0: failure is not considered
.GT. 0: Plastic strain to failure. When the plastic strain reaches this value, the element is deleted from calculation.
Field Comments
169MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
NUMINT Number of integration point which must fail before element is deleted.. If zero, all points must fail. This option applies to shell elements only.
MACF Material axes change flag:
=1 No Change; = 2 switch mateial axes a and b
=3 switch material axes a and c ; =4 switch material axes b and c
XP, YP, ZPP Coordinates of point p, for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
Field Comments
Materials170
MAT_ANISOTROPIC_PLASTIC
This anisotropic plastic material model is a simplified version of the MAT_ANISOTROPIC_VISCOPLASTIC model. This model applies to shell elements only.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Initial Yield Stress
LCSS Load Curve Id for effective Stress vs. effective plastic Strain
QRi, CRi Isotropic Hardening Parameters
QXi, CXi Kinematic Hardening Parameters
R00/F R00 for shell or F for solid
R45/G R45 for shell or G for solid
R90/H R90 for shell or H for solid
171MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
S11, S22, S33, S12 Yield Stress in the x, y, z and xy direction, respectively
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
4: Locally orthotropic in cylindrical coordinate system with the material axis determined by a vector v, and an originating point, P, which defines the centerline axis. This option is for solid elements only.
XP, YP, ZP Coordinates of point p, for AOPT=1
Ai Components of Vector a, for AOPT=2
Vi Components of Vector v, for AOPT=3
Di Components of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
Field Comments
Materials172
MAT_DAMAGE_1
Defines properties for a continuum damage mechanics material model which includes anisotropy and viscoplasticity. This model is applied to shell, thick shell and brick elements.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Initial Yield Stress
LCSS Load Curve Id for effective Stress vs. effective plastic Strain
LCDM Load Curve Id defining nonlinear damage (for FLAG = -1)
Qi, Ci Isotropic Hardening Parameters
EPSD Damage Threshold, rd
173MaterialsMaterials
S Damage Material Constant
EPSR Plastic strain at which material ruptures
DC Critical Damage valueDc
FLAG Flag for Localization
-1: Anisotropic damage
0: No calculation of localization due to damage
1: Flag those elements where local stabilization occurs
VK, VM Viscous Material Parameter
R00/F R00 for shell or F for solid
R45/G R45 for shell or G for solid
R90/H R90 for shell or H for solid
L, M, N Parameters (for solid elements only
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
4: Locally orthotropic in cylindrical coordinate system with the material axis determined by a vector v, and an originating point, P, which defines the centerline axis. This option is for solid elements only.
XP, YP, ZP Coordinates of point p, for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Field Comments
Materials174
See Also:• LS-DYNA Keyword User’s Manual
MAT_DAMAGE_2
Defines properties for an elastic viscoplastic material model combined with the continuum damage mechanics. This model is applied to shell, thick shell and brick elements.
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Tangent Modulus
FAIL Failure flag
=0: Failure due to plastic strain not considered
> 0: Plastic strain to failure considered. When the plastic strain reaches this value, the element is deleted from calculation.
Field Comments
175MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_ELASTIC_VISCOPLASTIC_THERMAL
Defines properties for an elastic viscoplastic material with thermal effects.
TDEL Minimum time step for Automatic Element Deletion
C, P Strain Rate Parameters
LCSS Load Curve Id defining effective Stress vs. effective plastic Strain
LCSR Load Curve Id defining Strain Rate Scaling Effect on Yield Stress
EPSD Damage Threshold, rd
S Damage Material Constant
DC Critical Damage valueDc
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
Field Comments
Materials176
See Also:• LS-DYNA Keyword User’s Manual
SIGY Initial Yield Stress
ALPHA Coefficient of thermal expansion
LCSS Load Curve Id for effective Stress vs. effective plastic Strain
QRi, CRi Isotropic Hardening Parameters
QXi, CXi Kinematic Hardening Parameters
C, P Viscous Material Parameters
LCE Load Curve Id defining Young’s Modulus vs. Temperature
LCPR Load Curve Id defining Poisson’s Ratio vs. Temperature
LCSIGY Load Curve Id defining Initial Yield Stress vs. Temperature
LCR Load Curve Id defining for Parameters QR1 and QR2 vs. Temperature
LCX Load Curve Id defining for Parameters QX1 and QX2 vs. Temperature
LCALPH Load Curve Id defining Coefficient of thermal expansion vs. Temperature
LCC Load Curve Id defining scaling Viscous material parameter C vs. Temperature
LCP Load Curve Id defining scaling Viscous material parameter P vs. Temperature
Field Comments
177MaterialsMaterials
MAT_JOHNSON_HOLMQUIST_CERAMICS
Defines properties for a material used to model ceramics, glass and other brittle materials.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear Modulus
A Intact normalized strength parameter
B Fractured normalized strength parameter
C Strength Parameter (for strain rate dependence)
M Fracture strength parameter (Pressure exponent)
N Intact strength parameter (Pressure exponent)
EPSI Reference Strain Rate
T Maximum Tensile Strength
SFMAX Maximum normalized Fractured Strength
HEL Hugoniot elastic limit
PHEL Pressure component at the at Hugoniot elastic limit
BETA Fraction of elastic energy loss converted to hydrostatic energy
Di Parameters for plastic strain to fracture
K1, K2 First and Second pressure coefficients
Materials178
See Also:• LS-DYNA Keyword User’s Manual
MAT_JOHNSON_HOLMQUIST_CONCRETE
This material model is used for concrete under high strain rates, large strains and high pressure.
K3 Elastic Constant (Note that K1 is the bulk modulus)
FS Failure Criteria
<0: Fails if (p* + t*) is negative (tensile failure)
0: No failure
>0: Fails if strain exceeds FS
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
G Shear Modulus
A Normalized Cohesive Strength
B Normalized Pressure Hardening
C Strain rate coefficient
N Pressure Hardening Exponent
Field Comments
179MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_FINITE_ELASTIC_STRAIN_PLASTICITY
An elasto-plastic material model with arbitrary stress-strain curve and arbitrary strain rate dependency. This material model uses a finite strain formulation allowing large elastic strains before yielding.
FC Quasi-static uniaxial compressive strength
T Maximum Tensile hydrostatic pressure
EPSO Reference Strain Rate
EFMIN Plastic strain before fracture
SFMAX Maximum Fractured Strength
PC Crushing Pressure
UC Crushing Volumetric Strain
PL Locking Pressure
UL Locking Volumetric Strain
D1, D2 Damage Constants
K1, K2, K3 Pressure Constants
FS Failure Type
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
Field Comments
Materials180
See Also:• LS-DYNA Keyword User’s Manual
MAT_LAYERED_LINEAR_PLASTICITY
Defines a layered elastoplastic material with an arbitrary stress-strain curve and arbitrary strain rate dependency.
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Tangent Modulus
FAIL Failure Flag
<0: User defined failure subroutine is called to determine failure
=0: Failure is not considered.
>0: Plastic strain to failure. When plastic strain reaches this value, the element is deleted from calculation.
TDEL Minimum time step size for automatic element deletion
C, P Strain Rate Parameters
LCSS Load Curve Id for effective Stress vs. effective plastic Strain
LCSR Load Curve Id defining Strain Rate Effect on Yield Stress
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
Field Comments
181MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_UNIFIED_CREEP
Defines properties of a material for elastic creep behavior.
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Tangent Modulus
FAIL Failure Flag
<0: User defined failure subroutine is called to determine failure
=0: Failure is not considered.
>0: Plastic strain to failure. When plastic strain reaches this value, the element is deleted from calculation.
TDEL Minimum time step size for automatic element deletion
C, P Strain Rate Parameters
LCSS Load Curve Id for effective Stress vs. effective plastic Strain
LCSR Load Curve Id defining Strain Rate Effect on Yield Stress
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
Field Comments
Materials182
See Also:• LS-DYNA Keyword User’s Manual
MAT_COMPOSITE_LAYUP
Defines the elastic response of composite layups that have an arbitrary number of layers through the shell thickness.
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
A Stress Coefficient
N Stress Exponent
M Time Exponent
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EA Young’s Modulus, a Direction
Field Comments
183MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
EB Young’s Modulus, b Direction
EC Young’s Modulus, c Direction
PRBA, PRCA, PRCB Poisson’s Ratio in the ba, ca and cb directions
GAB, GBC, GCA Shear Moduli in the ab, bc and ca directions
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
4: Locally orthotropic in cylindrical coordinate system with the material axis determined by a vector v, and an originating point, P, which defines the centerline axis. This option is for solid elements only.
XP, YP, ZP Coordinates of point p for AOPT=1 and 4
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3 and 4
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
Field Comments
Materials184
MAT_COMPOSITE_MATRIX
Defines the properties of materials used for the elastic response of composites where pre-integration is used to compute the extensional, bending, and coupling stiffness coefficients (available only for Belytschko-Tsay resultant shell formulation).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
Cij Coefficient of Stiffness Matrix
185MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
4: Locally orthotropic in cylindrical coordinate system with the material axis determined by a vector v, and an originating point, P, which defines the centerline axis. This option is for solid elements only.
XP, YP, ZP Coordinates of point p for AOPT=1 and 4
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3 and 4
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
Field Comments
Materials186
MAT_COMPOSITE_DIRECT
Defines properties for a material used for the elastic response of composites where pre-integration is used to compute the extensional, bending, and coupling stiffness coefficients (available only for Belytschko-Tsay resultant shell formulation).
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
Cij Coefficient of Stiffness Matrix
187MaterialsMaterials
MAT_GENERAL_NONLINEAR_6DOF_DISCRETE_BEAM
Defines the properties of a very general spring and damper. The beam is based on MAT_SPRING_GENERAL_NONLINEAR option. This model includes additional unloading options.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
KT Translational stiffness for unloading option 2.0
KR Rotational Stiffness for unloading option 2.0
UNLDOPT Unloading Option
OFFSET Offset Factor (between 0 and 1)
Materials188
See Also:• LS-DYNA Keyword User’s Manual
DAMPF Damping factor for stability
LCIDTR, LCIDTS, LCIDTT
Load Curve Id defining Translational Force resultant along r, s, t axes respectively vs. Translational Displacement.
LCIDRR, LCIDRS, LCIDRT
Load Curve Id defining Rotational Moment about r, s, t axes vs. Rotational Displacement.
LCIDTUR, LCIDTUS, LCIDTUT
Load Curve Id defining Translational Force resultant along r, s, t axes vs. Translational Displacement during unloading
LCIDRUR, LCIDRUS, LCIDRUT
Load Curve Id defining Rotational Moment about r, s, t axes vs. Rotational Displacement during unloading.
LCIDTDR, LCIDTDS, LCIDTDT
Load Curve Id defining Translational Damping Force along r, s, t axes vs. relative Translational Velocity.
LCIDRDR, LCIDRDS, LCIDRDT
Load Curve Id defining Rotational Damping Moment about r, s, t axes vs. relative Rotational Velocity.
LCIDTER, LCIDTES, LCIDTET
Load Curve Id defining Translational Damping Force scale factor vs. relative Displacement along r, s, t axes
LCIDRER, LCIDRES, LCIDRER
Load Curve Id defining Rotational Damping Moment scale factor vs. relative Displacement along r, s, t axes
UTFAILR, UTFAILS, UTFAILT
Translational Displacement along r, s, t at failure in Tension
WTFAILR, WTFAILS, WTFAILT
Rotational Displacement about r, s, t at failure in Tension
UCFAILR, UCFAILS, UCFAILT
Translational Displacement along r, s, t at failure in Compression
WCFAILR, WCFAILS, WCFAILT
Rotational Displacement about r, s, t at failure in Compression
IUR, IUS< IUT Initial Translational Displacement along r, s, t directions
IWR, IWS, IWT Initial Rotational Displacement about r, s, t axes
Field Comments
189MaterialsMaterials
MAT_GURSON
Defines the material properties for the Gurson dilational plastic material model (available only for shell elements).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
N Exponent in power law
Q1, Q2 Parameters
FC Critical void volume fraction
F0 Initial void volume fraction
EN Mean nucleation strain
SN Standard deviation SN of the normal distribution of εN
FN Void Volume Fraction of nucleating particles
ETAN Hardening Modulus
Materials190
See Also:• LS-DYNA Keyword User’s Manual
ATYP Hardening Type
1: Power Law
2: Linear
3: 8 points curve
FF0 Failure void volume fraction
Li Element Length Value
FFi Corresponding failure void volume fraction
LCSS Load Curve id defining effective Stress vs. effective plastic Strain
LCLF Load Curve Id defining Failure Void Volume Fraction vs. Element Length
NUMINT No of through thickness integration points which must fail before element is deleted
LCF0 Lod curve Id defining initial void volume fraction f0 vs. element length.
LCFC Lod curve Id defining initial void volume fraction fN vs. element length.
LCFN Lod curve Id defining initial void volume fraction f0 vs. element length.
VGTYP Type of void growth behavior:
.EQ. 0: void growth in tension, and void contraction in compression, but never below f0 (default).
.EQ. 1: void growth in tension only.
.EQ. 2: void growth in tension, and void contraction in compression, even below f0.
Field Comments
191MaterialsMaterials
MAT_GURSON_RCDC
Defines the material properties for the Gurson model with Wilkins Rc-Dc (for shell elements only).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
N Exponent in power law
Q1, Q2 Parameters
FC Critical void volume fraction
F0 Initial void volume fraction
EN Mean nucleation strain
SN Standard deviation SN of the normal distribution of εN
FN Void Volume Fraction of nucleating particles
Materials192
See Also:• LS-DYNA Keyword User’s Manual
ETAN Hardening Modulus
ATYP Hardening Type
1: Power Law
2: Linear
3: 8 points curve
FF0 Failure void volume fraction
Li Element Length Value
FFi Corresponding failure void volume fraction
LCSS Load Curve id defining effective Stress vs. effective plastic Strain
LCLF Load Curve Id defining Failure Void Volume Fraction vs. Element Length
NUMINT No of through thickness integration points which must fail before element is deleted
ALPHA Parameter α for Rc-Dc Model
BETA Parameter β for Rc-Dc Model
GAMMA Parameter γ for Rc-Dc Model
D0 Parameter D0 for Rc-Dc Model
B Parameter b for Rc-Dc Model
LAMBDA Parameter λ for Rc-Dc Model
DS Parameter ds for Rc-Dc Model
L Characteristic element length for Rc-Dc Material
Field Comments
193MaterialsMaterials
MAT_GENERAL_NONLINEAR_1DOF_DISCRETE_BEAM
Defines the material properties for a very general spring and damper. The beam is based on MAT_SPRING_GENERAL_NONLINEAR option and is a one dimensional version of 6DOF_DESCRETE_BEAM. This model includes additional unloading options.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
K Translational stiffness for unloading option 2
UNLDOPT Unloading option
OFFSET Offset to determine permanent set upon unloading if the UNLDOPT equals to 3.
DAMPF Damping factor for stability
LCIDT Load Curve Id defining Translational Force along the axis vs. relative Translational Displacement.
LCIDTU Load Curve Id defining Translational Force along the axis vs. relative Translational Displacement, during unloading
LCIDTD Load Curve Id defining Translational Damping Force along the local axis vs. relative Translational Velocity.
LCIDTE Load Curve Id defining Translational Damping Force scale factor along the local axis vs. relative Displacement.
UTFAIL Translational displacement at failure in tension
Materials194
See Also:• LS-DYNA Keyword User’s Manual
MAT_HILL_3R
Defines the properties for the Hill’s planar anisotropic material model with 3 R values.
UCFAIL Translational displacement at failure in compression
IU Initial translational displacement along the axis
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
Field Comments
195MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
HR Hardening Rule
1: Linear
2: Exponential
3: Load Curve
P1, P2 Material Parameters
R00, R45, R90 Lankford parameters
LCID Load Curve Id for the hardening rule
Epsilon_0 ε0 for determining initial yield stress for exponential hardening
SPI Parameter to redefine ε0
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
blank1, blank2, blank3 Blank Fields
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT=3
Field Comments
Materials196
MAT_MODIFIED_PIECEWISE_LINEAR_PLASTICITY
Defines an elasto-plastic material with an arbitrary stress versus strain curve and arbitrary strain rate dependency (available only for shell elements).
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Tangent Modulus
FAIL Failure flag
TDEL Minimum time step size for automatic element deletion
C, P Strain Rate Parameters
LCSS Load Curve Id defining effective Stress vs. effective plastic Strain
LCSR Load Curve Id defining Strain Rate scaling effect on Yield Stress
VP Formulation for Rate Effects
EPSTHIN Thinning Plastic Strain at Failure
EPSMAJ Major Plastic Strain at Failure
NUMINT No. of through thickness integration points that must fail before element is deleted
197MaterialsMaterials
MAT_PLASTICITY_COMPRESSION_TENSION
Defines an isotropic elastic-plastic material allowing different yield stress versus plastic strain curves in compression and tension.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
C, P Strain Rate Parameters
FAIL Failure Flag
TDEL Minimum time step size for automatic element deletion
LCIDC Load Curve Id defining Yield Stress vs. effective Plastic Strain in compression
LCIDT Load Curve Id defining Yield Stress vs. effective Plastic Strain in tension
Materials198
See Also:• LS-DYNA Keyword User’s Manual
LCSRC Optional load curve Id defining strain rate scaling effect on yield stress when the material is in compression
LCSRT Optional load curve Id defining strain rate scaling effect on yield stress when the material is in tension
SRFLAG Formulation for rate effects:
.EQ. 0: Total strain rate ; .EQ. 1: Deviatoric strain rate
LCFAIL Load curve Id defining failure strain vs. strain rate
PC Compressive mean stress (pressure) at which the yield stress follows the Load Curve ID, LCIDC
PT Tensile mean stress (pressure) at which the yield stress follows the Load Curve ID, LCIDT
PCUTC Pressure cut-off in compression
PCUTT Pressure cut-off in tension
PCUTF Pressure cut-off flag:
0 = inactive ; 1 = active
K (optional) bulk modulus for the viscoelastic material. If nonzero, a Kelvin type will be used.
NUM_RFS Number of terms used for shear relaxationmodulus/shear decay constant
GI1 (optional) shear relaxation modulus for the i-th term
BETAI1 (optional) shear decay constant for the i-th term
Field Comments
199MaterialsMaterials
MAT_MODIFIED_HONEYCOMB
Defines the properties for aluminum honeycomb crushable foam materials with anisotropic behavior.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
VF Relative volume at which honeycomb is fully compacted
MU Material viscosity coefficient
BULK Bulk Viscosity Flag
0: Not used
1: Active and MU=0
Materials200
LCA Load Curve ID, defining:
>0: Stress along a- axis vs. strain along a-axis
<0: Yield stress vs. the angle off the material axis is degrees
LCB Load Curve ID, defining:
>0: Stress along b- axis vs. strain along b-axis
<0: the strong axis stress vs. volumetric strain
LCC Load Curve ID, defining:
>0: Stress along c- axis vs. strain along c-axis
<0: the wreak axis stress vs. volumetric strain
LCS Load Curve ID, defining:
>0: Shear Stress vs. shear strain
<0: the damage curve defining the shear stress multiplier as a function of the shear strain component
LCAB Load Curve ID, defining:
>0: Shear Stress-ab vs. shear strain-ab
<0: the damage curve defining the shear stress-ab multiplier as a function of the shear strain-ab
LCBC Load Curve ID, defining:
>0: Shear Stress-bc vs. shear strain-bc
<0: the damage curve defining the shear stress-bc multiplier as a function of the shear strain-bc
LCCA Load Curve ID, defining:
>0: Shear Stress-ca vs. shear strain-ca
<0: the damage curve defining the shear stress-ca multiplier as a function of the shear strain-ca
LCSR Load Curve ID of Strain Rate effect scale factor vs. Strain Rate
EAAU, EBBU, ECCU Elastic Moduli in the a-, b-, and c- directions, in uncompressed configuration
GABU, GBCU, GCAU Shear Moduli in the ab, bc, ca planes in uncompressed configuration
Field Comments
201MaterialsMaterials
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
4: Locally orthotropic in cylindrical coordinate system with the material axis determined by a vector v, and an originating point, P, which defines the centerline axis. This option is for solid elements only.
MSCF Material axes change flag:
1 = no change (default) ; 2 = switch material axes a and b
3 = switch material axes a and c ; 4 = switch material axes b and c
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Di Component of Vector d, for AOPT=2
TSEF Tensile Strain at Element Failure
SSEF Shear Strain at Element Failure
VREF Relative volume at which the reference geometry is stored (for solid elements 1, 2, 3, 4, 10)
Field Comments
Materials202
See Also:• LS-DYNA Keyword User’s Manual
MAT_ARRIBA_BOYCE_RUBBER
Defines the material properties for hyperelastic rubber combined optionally with linear viscoelasticity.
TREF Element timestep size at which the reference geometry is stored
SHDFLG Flag defining treatment of damage from curves LCS, LCAB, LCBC, and LCBC (relevant only if LCA < 0):
.EQ. 0: damage reduces shear stress every time step
.EQ. 1: damage = (shear stress)/(undamaged shear stress)
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
K Bulk Modulus
G Shear Modulus
N Number of statistical links
Field Comments
203MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_HEART_TISSUE
Defines the material properties for heart tissue as described in the paper by Guccione, McCulloch and Waldman [1991]. This model is transversely anisotropic.
LCID Load Curve id defining Relaxation curve for shear
TRAMP Optional ramp time for loading
NT Number of Prony series terms in fit
NUM_RFS Number of viscoelastic constants
GIi Optional i-th shear Relaxation Modulus i
BETAIi Optional i-th shear Decay Constant
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
C, B1, B2, B3 Material Coefficients
Field Comments
Materials204
See Also:• LS-DYNA Keyword User’s Manual
P Pressure in muscle tissue
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
4: Locally orthotropic in cylindrical coordinate system with the material axis determined by a vector v, and an originating point, P, which defines the centerline axis. This option is for solid elements only.
MACF Material axes change flag:
1 = no change (default) ; 2 = switch material axes a and b
3 = switch material axes a and c ; 4 = switch material axes b and c
XP, YP, ZP Coordinates of point p for AOPT=1 and 4
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3 and 4
Di Component of Vector d, for AOPT=2
BETA Material Angle (Degrees), for AOPT = 3
Field Comments
205MaterialsMaterials
MAT_LUNG_TISSUE
Defines the material properties for a hyperelastic material model for heart tissue combined optionally with linear viscoelasticity.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
K Bulk Modulus
C, DELTA, ALPHA, BETA, C1, C2
Material Coefficients
LCID Relaxation curve for shear
TRAMP Optional ramp time for loading
NT Number of Prony series terms in fit
NUM_RFS Number of viscoelastic constants
GIi Optional i-th shear Relaxation Modulus
BETAIi Optional i-th shear Decay Constant
Materials206
MAT_SPECIAL_ORTHOTROPIC
This material model defines the properties for a material model developed for the Belytschko-Tsay and the C0 triangle shell elements. It is based on a resultant stress formulation. In plane behavior is treated separately from bending in order to model perforated materials such as television shadow masks.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
YS Yield Stress
EP Plastic Hardening Modulus
EiiP Young’s Modulus (in-plane) in i- direction
NUijP Poisson’s Ratio in plane ij
GijP Shear Modulus in Plane ij
EiiB Young’s Modulus (Bending) in i-direction
NUijB Poisson’s Ratio (Bending) in ij plane
G12B Shear Modulus (Bending) in 12 plane
207MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
3: Locally orthotropic with material axis determined by rotating the material axes about the element normal by an angle, BETA, from a line in the plane of the element defined by the cross product of the vector v with the element normal.
blank i Blank Field
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Material angle (degrees), for AOPT = 3
Field Comments
Materials208
MAT_MODIFIED_FORCE_LIMITED
This material model is an extension of MAT_FORCE_LIMITED (MAT_029). In addition to plastic hinge and collapse mechanisms, yield moments may be defined as a function of axial force. The moment transmitted by the hinge is defined by a moment-plastic rotation relationship.
209MaterialsMaterials
Materials210
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
211MaterialsMaterials
DF Damping Factor
AOPT Axial load curve option
0: Force vs. Strain
1: Force vs. change in length
YTFLAG Flag to allow beam to yield
ASOFT Axial elastic softening factor
M1, M2, ..., M8 Applied End Moments
LC1, LC2, ..., LC8 Load Curve Ids corresponding to applied end moments
LPSi Load Curve Id for plastic moment vs. rotation about s-axis at node i
SFSi Scale factor, plastic moment vs. rotation about s- axis at node i
YMSi Yield moment about s- axis at node i for interaction calculations
LPTi Load Curve Id for plastic moment vs. rotation about t-axis at node i
SFTi Scale factor, plastic moment vs. rotation about t- axis at node i
YMTi Yield moment about t- axis at node i for interaction calculations
LPR Load Curve Id for plastic torsional moment vs. rotation
SFR Load Curve Id for Scale factor vs. rotation
YMR Torsional Yield moment for interaction calculation
LYSi Load Curve Id for yield moment vs. axial force along axis s at node i
SYSi Load Curve Id for Scale factor applied to corresponding load curve LYSi
LYTi Load Curve Id for yield moment vs. axial force along axis t at node i
SYTi Load Curve Id for Scale factor applied to corresponding load curve LYTi
LYR Load Curve Id for yield moment vs. axial force for the torsional axis
LYS Load Curve Id for the Scale factor applying to LYR
HMS1_i Hinge moments for s axis at node 1 for hinge i
LPMS1_i Load Curve Id for plastic moment vs. plastic rotation for HMS1_i
HMS2_i Hinge moments for s axis at node 2 for hinge i
LPMS2_i Load Curve Id for plastic moment vs. rotation for HMS2_i
HMT1_i Hinge moments for t axis at node 1 for hinge i
LPMT1_i Load Curve Id for plastic moment vs. rotation for HMT1_i
HMT2_i Hinge moments for t axis at node 2 for hinge i
LPMT2_i Load Curve Id for plastic moment vs. rotation for HMT2_i
Field Comments
Materials212
See Also:• LS-DYNA Keyword User’s Manual
MAT_VACUUM
Defines the properties for a dummy material representing a vacuum in a multi-material Euler/ALE model.
See Also:• LS-DYNA Keyword User’s Manual
HMR_i Hinge moment for the torsional axis for hinge i
LPMR_i Load Curve Id for plastic moment vs. plastic rotation for HMR_i
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
KW_OPTION Title optional keywords
Field Comments
213MaterialsMaterials
MAT_RATE_SENSITIVE_POLYMER
Defines the properties for simulating an isotropic ductile polymer with strain rate effects. It uses uniaxial test data.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
D0 Reference Strain Rate (D0)
N Exponent for inelastic strain rate
Z0 Initial hardness of material (Z0)
q Parameter used in the constitutive equation
Omega Maximum internal stress
Materials214
MAT_TRANSVERSELY_ANISOTROPIC_CRUSHABLE_FOAM
Defines the properties for extruded foam material that is transversely anisotropic, crushable, and of low density with no significant Poisson effect.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E11, E22 Elastic Moduli in the 1(axial) and 2 (transverse) direction
E12 Elastic shear Modulus in the axial-transverse plane (E12 = E13)
G Shear Modulus
K Bulk Modulus for Contact Stiffness
I11 Load Curve Id for Nominal Axial Stress vs. Volumetric Strain
I22 Load Curve Id for Nominal Transverse Stress vs. Volumetric Strain (I22= I33)
I12 Load Curve Id for Shear Stress components 12 and 31 vs. Volumetric Strain (I22= I31)
I23 Load Curve Id for Shear Stress components 23 vs. Volumetric Strain
215MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
IAA Load Curve Id for Nominal stress vs. Volumetric strain at angle, ANG, relative to the material axis
NY Flag for symmetric yield surface
ANG Angle corresponding to Load Curve Id, IAA
MU Damping factor
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
ISCL Load Curve Id for the strain rate scale factor vs. volumetric strain rate. The yield rate is scaled by the value specified by the load curve.
MSCF Material axes change flag:
1 = no change (default) ; 2 = switch material axes a and b
3 = switch material axes a and c ; 4 = switch material axes b and c
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Components of vector v (for AOPT = 3 or 4)
Di Component of Vector d, for AOPT=2
Field Comments
Materials216
MAT_WOOD
Defines the material properties for a transversely isotropic material (available only for solid elements).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
217MaterialsMaterials
NPLOT Plotting Option
1: Parallel damage
2: Perpendicular damage
ITER Number of plasticity algorithm iterations
IRATE Rate effects option
0: Turn off
1: Turn on
HARD Perfect plasticity override
IFAIL Erosion perpendicular to the ground
0: No
1: Yes
IVOL Erode on negative volume or strain increments greater than 0.01
=0 No (default) ; =1 Yes
EL Parallel Normal Modulus
ET Perpendicular Normal Modulus
GLT Parallel Shear Modulus (GLT=GLR)
GTR Perpendicular Shear Modulus
PR Poisson’s Ratio
XT Parallel Tensile Strength
XC Parallel Compressive Strength
YT Perpendicular Tensile Strength
YC Perpendicular Compressive Strength
SXY Parallel Shear Strength
SYZ Perpendicular Shear Strength
GF1_I Parallel Fracture Energy in Tension
GF2_I Parallel Fracture Energy in Shear
BFIT Parallel softening Parameter
DMAX_I Parallel Maximum Damage
GF1_r Perpendicular Fracture Energy in Tension
GF2_r Perpendicular Fracture Energy in Shear
Field Comments
Materials218
DFIT Perpendicular Softening Parameter
DMAX_r Perpendicular Maximum Damage
FLPAR Parallel Fluidity Parameter for Tension and Shear
FLPARC Parallel Fluidity Parameter for Compression
POWPAR Parallel Power
FLPER Perpendicular Fluidity Parameter for Tension and Shear
FLPERC Perpendicular Fluidity Parameter for Compression
POWPER Perpendicular Power
NPAR Parallel Hardening initiation
CPAR Parallel Hardening Rate
NPER Perpendicular Hardening initiation
CPER Perpendicular Hardening Rate
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
MACF Material axes change flag:
=1 No Change; = 2 switch mateial axes a and b
=3 switch material axes a and c ; =4 switch material axes b and c
BETA Material angle in degrees (for AOP = 3)
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Di Component of Vector d, for AOPT=2
Vi Components of vector v( for AOP = 3 and 4)
Field Comments
219MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_WOOD_PINE
Defines the material properties for a transversely isotropic material (available only for solid elements). This model has default material properties for yellow pine.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
NPLOT Plotting Option
1: Parallel damage
2: Perpendicular damage
ITER Number of plasticity algorithm iterations
Materials220
IRATE Rate effects option
0: Turn off
1: Turn on
HARD Perfect plasticity override
IFAIL Erosion perpendicular to the ground
0: No
1: Yes
IVOL Erode on negative volume or strain increments greater than 0.01
=0 No (default) ; =1 Yes
MOIS Percentage moisture content
TEMP Temperature
QUAL_T Quality Factor Option in Tension
QUAL_C Quality Factor Option in Compression
UNITS Units Option
0: GPa, mm, msec, Kg/mm3, KN
1: MPa, mm, msec, g/mm3, N
2: MPa, mm, sec, Mg/mm3, N
3:Psi, inch, sec, lb-sec2/inch4, lb.
IQUAL Apply quality factors perpendicular to grain
0: Yes
1: No
Field Comments
221MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
MACF Material axes change flag:
=1 No Change; = 2 switch mateial axes a and b
=3 switch material axes a and c ; =4 switch material axes b and c
BETA Material angle in degrees (for AOP = 3)
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Di Component of Vector d, for AOPT=2
Vi Components of vector v( for AOP = 3 and 4)
Field Comments
Materials222
MAT_WOOD_FIR
Defines the material properties for a transversely isotropic material (available only for solid elements). This model has default material properties for Douglas Fir.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
NPLOT Plotting Option
1: Parallel damage
2: Perpendicular damage
ITER Number of plasticity algorithm iterations
IRATE Rate effects option
0: Turn off
1: Turn on
HARD Perfect plasticity override
223MaterialsMaterials
IFAIL Erosion perpendicular to the ground
0: No
1: Yes
IVOL Erode on negative volume or strain increments greater than 0.01
=0 No (default) ; =1 Yes
MOIS Percentage moisture content
TEMP Temperature
QUAL_T Quality Factor Option in Tension
QUAL_C Quality Factor Option in Compression
UNITS Units Option
0: GPa, mm, msec, Kg/mm3, KN
1: MPa, mm, msec, g/mm3, N
2: MPa, mm, sec, Mg/mm3, N
3:Psi, inch, sec, lb-sec2/inch4, lb.
IQUAL Apply quality factors perpendicular to grain
0: Yes
1: No
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
MACF Material axes change flag:
=1 No Change; = 2 switch mateial axes a and b
=3 switch material axes a and c ; =4 switch material axes b and c
Field Comments
Materials224
See Also:• LS-DYNA Keyword User’s Manual
MAT_PITZER_CRUSHABLE_FOAM
Defines the properties for a material model that simulates isotropic crushable foams with strain rate effects. It uses uniaxial and triaxial data.
BETA Material angle in degrees (for AOP = 3)
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Components of vector v( for AOP = 3 and 4)
Di Component of Vector d, for AOPT=2
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
K Bulk Modulus
G Shear Modulus
PR Poisson’s Ratio
TY Tension Yield
SRTV Young’s Modulus
LCPY Load Curve Id defining pressure vs. volumetric strain
Field Comments
225MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
LCUYS Load Curve Id defining uniaxial stress vs. volumetric strain
LCRS Load Curve Id defining Strain rate Scale Factor vs. Volumetric Strain rate
VC Viscous Damping Coefficient
DFLG Density Flag
0:Use Initial Density value
1: Use Current Density value
Field Comments
Materials226
MAT_SCHWER_MURRAY_CAP_MODEL
Defines the material properties for a three invariant extension of MAT_GEOLOGIC_CAP_MODEL (MAT_025) that also includes viscoplasticity for rate effects and damage mechanics to model strain softening.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
SHEAR Shear Modulus
BULK Bulk Modulus
GRUN Gruneisen Ratio
SHOCK Shock Velocity Parameter
PORE Flag for Pore Collapse
0: Yes
1: Constant Bulk Modulus
227MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
ALPHA, THETA, GAMMA, BETA
Shear Failure Parameters
EFIT, FFIT Dilitation damage mechanics parameters
ALPHAN, CALPHA Kinematic strain hardening parameters
R0 Initial Gap Surface ellipticity, R
X0 Initial Gap Surface J1 (mean stress) axis intercept
IROCK Material Flag
0: Soils (cap can contact)
1: Rock/Concrete
SECP Shear Enhanced Compaction
AFIT, BFIT, RDAM0 Ductile damage mechanics parameters
W, D1, D2 Plastic volume strain parameters
NPLOT History variable post-processed as effective plastic strain
EPSMAX Maximum permitted strain increment
CFIT, DFIT Brittle damage parameters
TFAIL Tensile Failure Stress
FAILFL Failure Flag (failed element)
DBETA, DDELTA Rounded Vertices Parameters
VPTAU Viscoplastic Relaxation time Parameter
ALPHA1 THETA1, GAMMA1, BETA1
Torsional scaling parameters
ALPHA2 THETA2, GAMMA2, BETA2
Triaxial extension scaling parameters
Field Comments
Materials228
MAT_1DOF_GENERALIZED_SPRING
Defines the properties for a linear spring or damper that allows different degrees-of-freedom at two nodes to be coupled with linear spring and/or damper.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
K Spring Stiffness
C Damping Constant
SCLNi Scale Factor on force at node i
DOFNi Active dof at node i
CIDi Local coordinate system Id at node 1 and node 2 respectively
229MaterialsMaterials
MAT_FHWA_SOIL
Defines the material properties for an isotropic material with damage for solid elements. The model has a modified Mohr-Coulomb surface for determining pressure dependent peak shear strength.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
NPLOT Plotting option
SPGRAV Specific gravity of soil
RHOWAT Density of water
VN, GAMMAR Viscoplastic parameters
ITERMAX Maximum number of plastic iterations
K Bulk Modulus
G Shear Modulus
PHIMAX Peak Shear strength (friction) angle (degrees)
AHYP Coefficient A for modified Drucker-Prager surface
COH Cohesion shear strength at zero confinement (overburden)
ECCEN Eccentricity parameter
AN Strain hardening percent of PHIMAX where nonlinear effects start
ET Strain hardening amount of nonlinear effects
Materials230
See Also:• LS-DYNA Keyword User’s Manual
MAT_FHWA_SOIL_NEBRASKA
Defines the material properties for a soil model with default property values for soils used at the University of Nebraska. Default units are in millimeter, milliseconds and kilograms.
See Also:• LS-DYNA Keyword User’s Manual
MCONT Moisture content in soil
PWD1 Parameter for pore water effects on Bulk Modulus
PWSK Skeleton Bulk Modulus
PWD2 Parameter for pore water effects on the effective pressure
PHIRES Minimum internal frictional angle (radians)
DINT Volumetric strain at initial threshold damage
VDFM Void formation energy
DAMLEV Level of damage that will cause element deletion
EPSMAX Maximum principal failure strain
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
FCTIM Factor to multiply milliseconds by to get desired time unit
FCTMAS Factor to multiply Kg by to get desired mass unit
FCTLEN Factor to multiply mm by to get desired length unit
Field Comments
231MaterialsMaterials
MAT_GAS_MIXTURE
Defines the material properties for a material model that simulates gas mixture and works in conjunction with the multi-material ALE formulation.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
IADIAB Flag for turning adiabatic compression logic ON/OFF
0 = ON ; 1 = OFF
RUNIV Universal gas constant in per-mole unit
CVi Heat Capacity at constant volume for upto eight different gases in per-mass unit gas (If RUNIV = 0 or blank)
MOLi Molecular weight of each ideal gas in the mixture (mass-unit/molde) (if RUNIV is nonzero)
CPi Heat Capacity at constant pressure for upto eight different gases in per-mass unit gas (If RUNIV = 0 or blank)
Materials232
See Also:• LS-DYNA Keyword User’s Manual
MAT_CFD
Defines the material properties for a material model that allows constant, isotropic fluid properties to be defined for the incompressible/low-Mach CFD solver.
Bi First order coefficient for a temperature dependent heat capacity at constant pressure for up to eight different gases (If RUNIV = 0 or blank)
Ci Second order coefficient for a temperature dependent heat capacity at constant pressure for up to eight different gases (If RUNIV = 0 or blank)
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RHO Fluid Density
MU Fluid Viscosity
K Thermal Conductivity
CP Heat Capacity
BETA Coefficient of expansion
TREF Reference Temperature
Field Comments
233MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_CFD_CONSTANT
Defines the material properties for a material model that allows constant, isotropic fluid properties to be defined for the incompressible/low-Mach CFD solver.
GX, GY, GZ Gravitational acceleration in the X, Y, Z direction
DIFFi Diffusivity for Species i
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RHO Fluid Density
MU Fluid Viscosity
K Thermal Conductivity
CP Heat Capacity
BETA Coefficient of expansion
TREF Reference Temperature
GX, GY, GZ Gravitational acceleration in the X, Y, Z direction
DIFFi Diffusivity for Species i
Field Comments
Materials234
See Also:• LS-DYNA Keyword User’s Manual
MAT_DESHPANDE_FLECK_FOAM
Defines the material properties for aluminum foam, used as a filler material in aluminum extrusions to enhance the energy absorbing capability of the extrusion.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
ALPHA Parameter to Control Shape of yield surface
GAMMA, ALPHA2, BETA, SIGP
Equation parameters
EPSD Densification strain
DERFI Type of derivation in Material subroutine
0: Numerical
1: Analytical
CFAIL Failure Strain
235MaterialsMaterials
MAT_COMPOSITE_MSC
Defines the material properties for a material model to simulate the progressive failure analysis for composite materials consisting of unidirectional and woven fabric layers.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EA Young’s Modulus - longitudinal direction
EB Young’s Modulus - transverse direction
EC Young’s Modulus - through thickness direction
PRBA, PRCA, PRCB Poisson’s Ratio in ba, ca, and cb directions
GAB, GBC, GCA Shear Stress in ab bc, and ca directions
Materials236
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
MACF Material Axes change flag:
= 1 no change (default)
= 2, switch material axes a and b
= 3, switch material axes a and c
= 4, switch material axes b and c
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Layer in-plane rotational Angle (degrees)
SAT Longitudinal Tensile Strength
SAC Longitudinal Compressive Strength
SBT Transverse Tensile Strength
SBC Transverse Compressive Strength
SCT Through thickness Tensile Strength
SFC Crush Strength
SFS Fiber mode shear strength
SAB, SBC, SCA Matrix mode Shear Strength in ab bc, and ca planes
SFFC Scale factor for residual compressive strength
Field Comments
237MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
AMODEL Material Model
1: Unidirectional layer model
2: Fabric layer model
PHIC Coulomb friction angle
E_LIMT Element eroding axial strain
S_DELM Scale factor for delamination criteria
OMGMX Limit damage parameter for elastic modulus
ECRSH Limit compressive volume strain for element eroding
EEXPN Limit tensile volume strain for element eroding
CERATE1 Coefficient for strain rate dependent strength properties
AM1 Coefficient for strain rate softening property for fiber in a direction
Field Comments
Materials238
MAT_COMPOSITE_MSC_DMG
Defines the material properties for a material model to simulate the progressive failure analysis for composite materials consisting of unidirectional and woven fabric layers.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
EA Young’s Modulus - longitudinal direction
EB Young’s Modulus - transverse direction
EC Young’s Modulus - through thickness direction
PRBA, PRCA, PRCB Poisson’s Ratio in ba, ca, and cb directions
GAB, GBC, GCA Shear Stress in ab bc, and ca directions
239MaterialsMaterials
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
MACF Material Axes change flag:
= 1 no change (default)
= 2, switch material axes a and b
= 3, switch material axes a and c
= 4, switch material axes b and c
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Layer in-plane rotational Angle (degrees)
SAT Longitudinal Tensile Strength
SAC Longitudinal Compressive Strength
SBT Transverse Tensile Strength
SBC Transverse Compressive Strength
SCT Through thickness Tessile Strength
SFC Crush Strength
SFS Fiber mode shear strength
Sij Transverse Shear Strength ij
SFFC Scale factor for residual compressive strength
Field Comments
Materials240
See Also:• LS-DYNA Keyword User’s Manual
MAT_MODIFIED_CRUSHABLE_FOAM
Defines the material properties for a material model to simulate crushable foam with optional damping, tension cutoff and strain rate effects. Unloading is fully elastic. Tension is treated as elastic-perfectly-plastic at the tension cutoff value.
AMODEL Material Model
1: Unidirectional
2: Fabric
PHIC Coulomb friction angle
E_LIMT Element eroding axial strain
S_DELM Scale factor for delamination criteria
OMGMX Limit damage parameter for elastic modulus
ECRSH Limit compressive volume strain
EEXPN Limit tensile volume strain
CERATEi Coefficient for strain rate dependent strength parameter, axial moduli, shear moduli, transverse moduli
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
Field Comments
241MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_QUASILINEAR_VISCOELASTIC
Defines the properties for a material model to simulate a quasi-linear, isotropic, viscoelastic material which represents biological soft tissue such as brain, kidney, etc.
E Young’s Modulus
PR Poisson’s Ratio
TID Load Curve Id defining Yield Stress vs. Volumetric Strain
TSC Tensile Stress Cutoff
DAMP Rate sensitivity via damping coefficient
NCYCLE Number of cycles to determine volumetric strain rate
SRCLMT Strain rate change limit
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
K Bulk Modulus
LC1 Load Curve Id for the Relaxation function in shear
Field Comments
Materials242
See Also:• LS-DYNA Keyword User’s Manual
LC2 Load Curve Id for the instantaneous Elastic response in shear
N No. of Prony series terms in fit
GSTART Starting value for least square fit
M No. of terms used to determine the instantaneous elastic response
S0 Strain output option to be plotted as component 7 in LS-TAURUS
0: Maximum principal strain
1: Maximum Magnitude of principal strain
2: Maximum Effective strain
E_MIN Minimum strain rate used to generate the load curve fron Ci
E_MAX Maximum strain rate used to generate the load curve fron Ci
GAMA1, GAMA2 Material failure parameters
KF Material failure parameter that controls the enclosed by the failure surface.
.LE 0, ignore failure criterion.
.GE. 0, use actual K value for failure criterion.
EH Damage parameter
FORM Formulation of Model.
=0 original model by Fung which relaxes to a zero stress state as time approaches to infinity.
= 1 Alternative model which relaxes to the quasistatice elastic response
C1 to C6 Coefficients of the instanteneous elastic response in compression and tension
Field Comments
243MaterialsMaterials
MAT_HILL_FOAM
Defines the properties for a material model to simulate a highly compressible foam based on strain energy function, proposed by Hill. This model takes Poisson’s ratio effects into account.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
K Bulk Modulus
N Material constant
MU Damping coefficient
LCID Load Curve Id defining Force per unit area vs. Stretch Ratio
FITTYPE Type of fit
1: Uniaxial
2: Biaxial
LCSR Load Curve Id defining uniaxial (or biaxial, depending on FITTYPE) Stress ratio vs. Transverse Stretch Ratio
R Mullinus effect model r coefficient
M Mullinus effect model m coefficient
Materials244
MAT_VISCOELASTIC_HILL_FOAM
Defines the properties for a material model to simulate a highly compressible foam based on strain energy function, proposed by Hill. with extensions to include large strain viscoelasticity proposed by Feng and Hallquist [2002].
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
K Bulk Modulus
N Material constant
MU Damping coefficient
LCID Load Curve Id defining Force per unit area vs. Stretch Ratio
FITTYPE Type of fit
1: Uniaxial
2: Biaxial
LCSR Load Curve Id defining uniaxial (or biaxial, depending on FITTYPE) Stress ratio vs. Transverse Stretch Ratio
LCVE Load Curve Id defining the Relaxation function in shear
NT No. of Prony series terms in fit
GSTART Starting value for least square fit
245MaterialsMaterials
MAT_LOW_DENSITY_SYNTHETIC_FOAM
Defines the properties of rate independent low density foams exhibiting considerably reduced properties in the loading-unloading curve after the first loading cycle.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
LCID1 Load Curve Id defining nominal Stress vs. Strain for the first loading cycle
LCID2 Load Curve Id defining nominal Stress vs. Strain for loading cycles after the first loading cycle is completed
HU Hysteric unloading factor between 0 and 1
BETA Decay constant to model creep in unloading
DAMP Viscous coefficient
SHAPE Shape factor for unloading
FAIL Failure option after cutoff stress
0: Tensile Stress remains at cutoff
1: Tensile Stress resets to zero
Materials246
See Also:• LS-DYNA Keyword User’s Manual
MAT_LOW_DENSITY_SYNTHETIC_FOAM_ORTHO
Defines the properties of rate independent low density foams exhibiting considerably reduced properties in the loading-unloading curve after the first loading cycle. This material model considers any orthotropic behavior after the first loading and unloading cycle of the material in the orthogonal directions.
BVFLAG Bulk viscosity activation flag
0: No
1: Active
ED Optional Young’s relaxation modulus for rate effects
BETA1 Optional decay constant
KCON Stiffness coefficient for contact interface stiffness
REF Use reference geometry to initialize stress tensor
0: Off
1: On
TC Tension Cutoff Stress
RFLAG Rate type for input:
= 0, LCID1 and LCID2 should be input as functions of true strain rate
= 1, LCID1 and LCID2 should be functions of engineering strain rate
DIRT Strain rate averaging flag:
= 0, use weighted running average
.LE. 0, average the last eleven values
.GT. 0, average over the last DIRT time units
K
GAMA1, GAMA2 Material failure parameters
EH Damage parameter
Field Comments
247MaterialsMaterials
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
LCID1 Load Curve Id defining nominal Stress vs. Strain for the first loading cycle
LCID2 Load Curve Id defining nominal Stress vs. Strain for loading cycles after the first loading cycle is completed
HU Hysteric unloading factor between 0 and 1
BETA Decay constant to model creep in unloading
DAMP Viscous coefficient
SHAPE Shape factor for unloading
FAIL Failure option after cutoff stress
0: Tensile Stress remains at cutoff
1: Tensile Stress resets to zero
Materials248
See Also:• LS-DYNA Keyword User’s Manual
BVFLAG Bulk viscosity activation flag
0: No
1: Active
ED Optional Young’s relaxation modulus for rate effects
BETA1 Optional decay constant
KCON Stiffness coefficient for contact interface stiffness
REF Use reference geometry to initialize stress tensor
0: Off
1: On
TC Tension Cutoff Stress
RFLAG Rate type for input:
= 0, LCID1 and LCID2 should be input as functions of true strain rate
= 1, LCID1 and LCID2 should be functions of engineering strain rate
DIRT Strain rate averaging flag:
= 0, use weighted running average
.LE. 0, average the last eleven values
.GT. 0, average over the last DIRT time units
K
GAMA1, GAMA2 Material failure parameters
EH Damage parameter
Field Comments
249MaterialsMaterials
MAT_SIMPLIFIED_RUBBER/FOAM
Defines the properties of a rubber amd foam model defined by a single uniaxial load curve or by a family of curves at discrete strain rates.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
KM Linear Bulk Modulus
MU Damping coefficient
G Shear Modulus
SIGF Limit stress for frequency independent, frictional, damping
REF Use Reference Geometry (defined in *INITIAL_FOAM_REFERENCE_GEOMETRY) to initialize the stress tensor. 0 = ON ; 1 = OFF
PRTEN Tensile Poisson’s ratio.
= 0 indicates that PR/BETA will serve as Poisoon’s ratio for both tension and compression in shells. Otherwise, PR/BETA will serve as Poisoon’s ratio for compression in shells.
SGL Specimen Gauge Length
SW Specimen Width
ST Specimen Thickness
Materials250
See Also:• LS-DYNA Keyword User’s Manual
LCID Load Curve Id defining Force vs. Actual change in gauge length
TENSION Parameter to control rate effect
-1: Rate effects are treated for loading either in tension or in compression (but not for unloading)
0: Rate effects are treated for loading compressive loading only
1:Rate effects are treated identically for tension and compressive loading only
RTYPE Strain rate type
0: True
1: Engineering
AVGOPT Averaging option to determine strain rate (to reduce numerical noise)
0: Simple average of twelve time steps
1: Running 12-point average
PR/BETA If value is between 0.0 and 0.5 (exclusive), the value give here is taken as Poisson’s ratio. If value is exactly 0.0 (zero), an incompressible rubber like behavior is assumed, and a value of 0.495 is used inside the software. If zero Poisson’s ratio is desired, use a small value such as 0.001 for PR.
K Material failure parameter that controls the enclosed by the failure surface.
.LE 0, ignore failure criterion.
.GE. 0, use actual K value for failure criterion.
GAMA1, GAMA2 Material failure parameters
EH Damage parameter
Field Comments
251MaterialsMaterials
MAT_SEISMIC_BEAM
Defines the properties of a material characterized by lumped plasticity to be developed at the ‘node 2’ end of Belytschko-Schwer beams. The plastic yield surface allows interaction between the two moments and the axial force.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
AOPT Axial force option
0: Axial Load Curves are Collapse Load vs. Strain
NE. 0: Axial Load Curves are Collapse Load vs. Change in Length
Materials252
FTYPE Formulation type for interaction
1: Parabolic coefficients
2: Japanese Code, axial force and major axis bending
DEGRADE Flag for degrading moment behavior
0 = behavior as in previous versions
1 = Fatigue-type moment-rotation behavior
2 = FEMA-type moment-rotation behavior
IFEMA Flag for input of FEMA thresholds
= 0 No inputs ; 1 = Input of rotation thresholds only
=2 Input of rotation and axial strain thresholds
LCPMS Load Curve Id for Plastic Moment vs. Rotation about s at node 2
SFS Scale factor on s -moment at node 2
LCPMT Load Curve Id for Plastic Moment vs. Rotation about t at node 2
SFT Scale factor on t -moment at node 2
LCAT Load Curve Id for axial tensile yield force vs. total tensile strain (or elongation, see AOPT option)
SFAT Scale factor for axial tensile force
LCAC Load Curve Id for axial compressive force vs. strain/elongation
SFAC Scale factor for axial compressive force
ALPHA, BETA, GAMMA, DELTA, A, B
Parameters to define yield surface
FOFFS Force offset for Yield Surface
SIGY Yield Stress
D Depth of section used for interaction curve
W Width of section used for interaction curve
TF Flange Thickness of section used for interaction curve
TW Web Thickness of section used for interaction curve
PR1 - PR4 Plastic rotation thresholds 1 to 4
TS1 - TS4 Tensile axial strain hresholds 1 to 4
CS1 - CS4 Compressive axial strain hresholds 1 to 4
Field Comments
253MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_SOIL_BRICK
Defines the properties of clay like soils accurately.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
RLAMDA, RKAPPA, RIOTA, RBETAi
Material coefficient
RMU Shape factor coefficient
RNU Poisson’s ratio
RLCID Load Curve Id referring to a curve defining up to ten pairs of ‘string-length’ vs. G/Gmax points.up to 10 points of string-length vs. Gmax
TOL User defined tolerance for convergence checking
PGCL Pre consolidation ground level
SUB-INC User defined strain increment size
BLK Elastic bulk stiffness of the soil
GRAV Gravitational acceleration
Materials254
See Also:• LS-DYNA Keyword User’s Manual
MAT_DRUCKER_PRAGER
Defines the properties of materials such as soils modeled with the modified Drucker-Prager yield surface.
THEORY Version of material subroutine used
0 (default) = 1995 version (vectorized) ; 4 = 1995 version (unvectorized)
RVHNH Anisotropy parameter
XSICRIT, ALPHA Anisotropy parameters
RVH Anisotropy ratio (Ev/Eh)
RNU21 Anisotropy ratio (ν2/ν1)
ANISO_4 Anisotropy parameter
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
GMOD Elastic Shear Modulus
RNU Poisson’s ratio
RKF Failure surface shape parameter
Field Comments
255MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
PHI Angle of friction (radians)
CVAL Cohesive Value
PSI Dilation angle (radians)
STR_LIM Factor for calculating minimum shear strength of material which is calculated as STR_LIM*CVAL
GMODDP Depth at which shear modulus is correct
PHIDP Depth at which friction angle is correct
CVALDP Depth at which cohesive value is correct
PSIDP Depth at which dilation angle is correct
GMODGR Gradient at which shear modulus increases with depth
PHIGR Gradient at which friction angle increases with depth
CVALGR Gradient at which cohesive value increases with depth
PSIGR Gradient at which dilation angle increases with depth
Field Comments
Materials256
MAT_RC_SHEAR_WALL
Defines the properties of materials to model cyclic shear loading of reinforced concrete walls (available only for shell elements).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
TMAX Ultimate shear stress
257MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
Fc Unconfirmed compressive strength of Concrete
PREF Percent reinforcement
FYIELD Yield stress of reinforcement
SIG0 Overburden stress
UNCONV Unit conversion factor, to compute ultimate tensile stress of Concrete
ALPHA Shear span factor
FT Cracking stress in direct tension
ERIENF Young’s Modulus for reinforcement
A, B, C, D, E Hysteresis constants to determine shape of the hysteresis loops
F Strength gradient factor
Yi Shear strain points on stress vs. strain curve
Ti Shear stress points on stress vs. strain curve
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Vi Component of Vector v, for AOPT=3
Di Component of Vector d, for AOPT=2
BETA Layer in-plane rotational Angle
Field Comments
Materials258
MAT_CONCRETE_BEAM
Defines an elasto-plastic material with an arbitrary stress-strain curve and arbitrary strain rate dependency. Also, failure based on plastic strain or a minimum time step can be defined.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
E Young’s Modulus
PR Poisson’s Ratio
SIGY Yield Stress
ETAN Tangent Modulus
C, P Strain Rate Parameters
FAIL Failure Flag
TDEL Minimum time step size for automatic element deletion
LCSS Load Curve Id defining Effective Stress vs. Effective Plastic Strain in compression
LCSR Load Curve Id defining Strain rate effects on Yield Stress
259MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_GENERAL_SPRING_DISCRETE_BEAM
Defines the properties of materials with elastic and elastoplastic springs with damping to be represented by discrete beam elements using six springs, each acting along one of the six local degrees-of-freedom.
NOTEN No-tension flag
0: Takes tension
1: Does not take Tension
2: Takes tension upto value given by TENCUT (Tension cutoff)
TENCUT Tension cutoff stress
SDR Stiffness degradation factor
Field Comments
Materials260
For elastic behavior, use a load curve of yield force or moment versus displacement or rotation. For inelastic case, use a load curve of yield force or moment versus plastic deflection or rotation.
261MaterialsMaterials
Materials262
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
DOFi Active degree-of-freedom
TYPEi Behavior
0: Elastic
1: Inelastic
Ki Elastic loading/unloading stiffness
Di Optional viscous damping coefficient
CDFi Compressive displacement at failure
TDFi Tensile displacement at failure
FLCIDi Load Curve Id defining Force (or Moment) vs. Displacement for nonlinear elastic (TYPE1 = 0). For inelastic behavior, this curve defines the yield force vs. plastic deflection.
HLCIDi Load Curve Id defining Force vs. Relative Velocity
C1_i, C2_i Damping coefficients
DLEi Scale factor for time unit
GLCIDi Load Curve Id defining scale factor vs. deflection for HLCIDi
263MaterialsMaterials
MAT_SEISMIC_ISOLATOR
Defines the properties of materials used as sliding and elastometric seismic isolation bearings. This material model uses a bi-directional coupled plasticity theory (available only for discrete beam elements).
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
A, GAMMA, BETA Non dimensional variable
DISPY Yield displacement
STIFFV Vertical stiffness
ITYPE Type
0: Sliding
1: Elastomeric
PRELOAD Vertical preload
DAMP Damping ratio
MXi Moment factor at end i in local x direction
MYi Moment factor at end i in local y direction
FMAX Maximum dynamic friction coefficient
Materials264
See Also:• LS-DYNA Keyword User’s Manual
DELF Difference between maximum and Static Friction coefficient
AFRIC Velocity multiplier in sliding friction equation
RADX Radius for sliding in local x direction
RADY Radius for sliding in local y direction
RADB Radius of retaining ring
STIFFL Stiffness for lateral contact against retaining ring
STIFFTS Stiffness for tensile vertical response (sliding)
FORCEY Yield force
ALPHA Ratio of post and pre yielding stiffness
STIFFT Stiffness for tensile vertical response (elastomeric)
DFAIL Lateral displacement at which isolator fails
FMAXYC Maximum dynamic friction coefficient in compression in local y-direction
FMAXXT Maximum dynamic friction coefficient in tension in local x-direction
FMAXYT Maximum dynamic friction coefficient in tension in local y-direction
YLOCK Stiffness locking the local y- displacement (optional in single axis sliding)
Field Comments
265MaterialsMaterials
MAT_JOINTED_ROCK
Defines the properties of jointed rocks.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
RO Mass Density of the material
GMOD Elastic Shear Modulus
RNU Poisson’s ratio
RKF Failure surface shape parameter
PHI Angle of friction (radians)
CVAL Cohesive Value
PSI Dilation angle (radians)
STR_LIM Factor for calculating minimum shear strength of material which is calculated as STR_LIM*CVAL
NPLANES No of joint planes
Materials266
See Also:• LS-DYNA Keyword User’s Manual
ELASTIC Flag for Elastic Behavior
0: Non elastic
1: Elastic
LCCPDR Load Curve Id for extra cohesion for parent material (dynamic relaxation)
LCCPT Load Curve Id for extra cohesion for parent material (transient)
LCCJDR Load Curve Id for extra cohesion for joints (dynamic relaxation)
LCCJT Load Curve Id for extra cohesion for joint material (transient)
LCSFAC Load Curve Id giving factor on Strength vs. Time
GMODDP Depth at which shear modulus is correct
PHIDP Depth at which friction angle is correct
CVALDP Depth at which cohesive value is correct
PSIDP Depth at which dilation angle is correct
GMODGR Gradient at which shear modulus increases with depth
PHIGR Gradient at which friction angle increases with depth
CVALGR Gradient at which cohesive value increases with depth
PSIGR Gradient at which dilation angle increases with depth
DIPi Angle (degrees) of plane below the horizontal
STRIKEi Plan view angle (degrees) of downhill vector drawn on the plane
CPLANEi Cohesion for shear behavior on plane i
FRPLANEi Friction angle for shear behavior on plane i
TPLANEi Tensile strength across plane i
SHRMAXi Maximum shear stress on plane i
LOCALi DIP and STRIKE Coordinate System flag
0: with respect to Global axes
1: with respect to element local axes
Field Comments
267MaterialsMaterials
MAT_SPRING_ELASTIC
Defines the properties of a translational or rotational elastic spring placed between two nodes. Only one degree of freedom is connected.
See Also:• LS-DYNA Keyword User’s Manual
MAT_DAMPER_VISCOUS
Defines the properties of translational and rotational dampers located between two nodes. Only one degree of freedom is connected.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
K Elastic Stiffness (Translational or Rotational)
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
DC Damping Constant (Force/Displacement rate or Moment/Rotation rate)
Materials268
See Also:• LS-DYNA Keyword User’s Manual
MAT_SPRING_ELASTOPLASTIC
Defines the properties of discrete springs providing an elastoplastic translational or rotational spring with isotropic hardening located between two nodes. Only one degree of freedom is connected.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
K Elastic Stiffness (Translational or Rotational)
KT Tangent Stiffness
FY Yield Force or Moment
269MaterialsMaterials
MAT_SPRING_NONLINEAR_ELASTIC
Defines the properties of discrete springs providing a nonlinear elastic translational or rotational spring with arbitrary force versus displacement and moment versus rotation data. Only one degree of freedom is connected.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
LCD Load Curve Id defining Force vs. Displacement or Moment vs. Rotation
LCR Load Curve Id defining Scale factor on Force or Moment as a function of relative velocity, or rotational velocity respectively
Materials270
MAT_DAMPER_NONLINEAR_VISCOUS
Defines the properties of discrete dampers providing a viscous translational or rotational damper with arbitrary force versus velocity or a moment versus rotational velocity data. Only one degree of freedom is connected.
See Also:• LS-DYNA Keyword User’s Manual
MAT_SPRING_GENERAL_NONLINEAR
Defines the properties of discrete springs providing a general nonlinear translational or rotational spring with arbitrary loading and unloading data. It also considers hardening or softening. Only one degree of freedom is connected.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
LCDR Load Curve Id defining the Force vs. rate of Displacement or Moment vs. rate of Rotation relationship
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
271MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_SPRING_MAXWELL
Defines the properties of discrete springs providing a three Parameter Maxwell Viscoelastic translational or rotational spring. Only one degree of freedom is connected.
MID Material identification number (Integer > 0)
LCDL Loading Curve Id for Force vs. Displacement or Moment vs. Rotation
LCDU Unloading Load Curve Id for Force vs. Displacement or Moment vs. Rotation
BETA Hardening parameter
TYI Initial Yield force in tension
CYI Initial Yield force in compression
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
K0 Short term stiffness
KI Long term stiffness
BETA Decay constant
TC Cutoff time. After this time a constant force/moment transmitted
Field Comments
Materials272
See Also:• LS-DYNA Keyword User’s Manual
MAT_SPRING_INELASTIC
Defines the properties of discrete springs and dampers providing an inelastic tension or compression only, translational or rotational spring.
See Also:• LS-DYNA Keyword User’s Manual
FC Force/Moment after cutoff time
COPT Time implementation option
0: Incremental time change
1: Continuous time change
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
LCFD Load Curve Id defining the Force/Torque vs. Displacement/Twist relationship
KU Unloading Stiffness
CTF Flag for compression/tension
-1: Tension only
1: Compression only (Default CTF value is 0, which is same as 1)
Field Comments
273MaterialsMaterials
MAT_SPRING_TRILINEAR_DEGRADING
Defines the properties of concrete shear walls under seismic loading modelled as discrete elements. It represents cracking of the concrete, yield of the reinforcement, and overall failure.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
DEFL1 Deflection at point where concrete cracks
F1 Force corresponding to DEFL1
DEFL2 Deflection at reinforcement yield
F2 Force corresponding to DEFL2
DEFL3 Deflection at complete failure
F3 Force corresponding to DEFL3
FFLAG Failure Flag
Materials274
MAT_SPRING_SQUAT_SHEARWALL
Defines the properties of squat shear walls modelled as discrete elements. This material model allows concrete cracking, reinforcement yield, and ultimate strength, followed by degradation of strength, leading finally to collapse.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
A14, B14, C14, D14, E14
Material coefficient
LCID Load Curve Id referencing the maximum strength envelope curve
FSD Sustained strength reduction factor
275MaterialsMaterials
MAT_SPRING_MUSCLE
Defines the properties for discrete springs and dampers. This is a Hill-type muscle model with activation.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
L0 Initial muscle length
VMAX Maximum CE shortening velocity
SV Scale factor for Vmax vs. Active State
A Scale factor for Activation Level vs. Time function
FMAX Peak isometric force
TL Scale factor for Active tension vs. length function
TV Scale factor for Active tension vs. velocity function
FPE Scale factor for Force vs. length function, for parallel elastic element
LMAX Relative length at FPE=FMAX
KSH Constant governing the exponential rise of FPE
LCID_SV Load Curve Id defining Vmax vs. active state
LCID_A Load Curve Id defining Active level vs. Time function
LCID_TL Load Curve Id defining Active tension vs. Length function
LCID_TV Load Curve Id defining Active tension vs. velocity function
LCID_FPE Load Curve Id defining Force vs. Length function
Materials276
MAT_THERMAL_ISOTROPIC
Defines isotropic thermal properties of materials in coupled structural/thermal and thermal only analyses.
See Also:• LS-DYNA Keyword User’s Manual
MAT_THERMAL_ORTHOTROPIC
Defines orthotropic thermal properties in coupled structural/thermal and thermal only analyses.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
TRO Thermal Density
TGRLC Thermal generation rate value
TGMULT Thermal generation rate multiplier
TLAT Phase chnage temperature
HLAT Latent heat
HC Heat capacity
TC Thermal conductivity
277MaterialsMaterials
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
TRO Thermal Density
TGRLC Thermal generation rate value
TGMULT Thermal generation rate multiplier
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by3 vectors below.
TLAT Phase chnage temperature
HLAT Latent heat
Materials278
See Also:• LS-DYNA Keyword User’s Manual
MAT_THERMAL_ISOTROPIC_TD
Defines temperature dependent isotropic thermal properties in coupled structural/thermal and thermal only analyses.
K1, K2, K3 Thermal conductivity in local x, y and z, respectively
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Di Component of Vector d, for AOPT=2
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
TRO Thermal Density
TGRLC Thermal generation rate value
Field Comments
279MaterialsMaterials
See Also:• LS-DYNA Keyword User’s Manual
MAT_ORTHOTROPIC_TD
Defines temperature dependent orthotropic thermal properties in coupled structural/thermal and thermal only analyses.
TGMULT Thermal generation rate multiplier
TLAT Phase chnage temperature
HLAT Latent heat
LC_C Load Curve defining Heat capacity (C) Vs. Temperature
LC_K Load Curve defining Thermal Conductivity (K) Vs. Temperature
Field Comments
Materials280
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
TRO Thermal Density
TGRLC Thermal generation rate value
TGMULT Thermal generation rate multiplier
AOPT Material Axes option
0: Locally orthotropic with material axes determined by element nodes 1, 2, and 4. (Node 1 is the local origin, Node 2 is along the local a- axis; Local c-axis is the cross product of local a-axis, and the vector from node 1 to node 4; Local b- axis is the cross product of loca c- and a- axes.)
1: Locally orthotropic with material axis determined by a point in space, and the global location of the element center; this is the a- direction. This option is for solid elements only.
2: Globally orthotropic with material axis determined by vectors below.
LC_C Load Curve defining Heat capacity Vs. Time
LC_KX Load Curve defining Thermal conductivity in local X Vs. Time
LC_KY Load Curve defining Thermal conductivity in local Y Vs. Time
LC_KZ Load Curve defining Thermal conductivity in local Z Vs. Time
XP X-coordinate of point p for AOPT=1
YP Y-coordinate of point p for AOPT=1
ZP Z-coordinate of point p for AOPT=1
Ai Component of Vector a, for AOPT=2
Di Component of Vector d, for AOPT=2
281MaterialsMaterials
MAT_THERMAL_ISOTROPIC_PHASE_CHANGE
Defines temperature dependent isotropic properties with phase changes in coupled structural/thermal and thermal only analyses.
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
TRO Thermal Density
TGRLC Thermal generation rate value
TGMULT Thermal generation rate multiplier
LC_C Load Curve defining Heat capacity Vs. Temperature
LC_K Load Curve defining Thermal conductivity Vs. Temperature
SOLT Solid Temperature
LIQT Liquid Temperature
LH Latent Heat
Materials282
See Also:• LS-DYNA Keyword User’s Manual
MAT_THERMAL_ISOTROPIC_TD_LC
Defines temperature dependent isotropic thermal properties by specifying a load curve in coupled structural/thermal and thermal only analyses.
See Also:• LS-DYNA Keyword User’s Manual
Field Comments
Title Unique name identifying material model
Desc Optional description of the material model
TITLE_OPTION If selected material title option is used
MID Material identification number (Integer > 0)
TRO Thermal Density
TGRLC Thermal generation rate value
TGMULT Thermal generation rate multiplier
HCLC Load Curve Id specifying Heat capacity vs. Temperature
TCLC Load Curve Id specifying Thermal conductivity vs. Temperature
TGRLCID Load Curve Id specifying Thermal generation rate curve number
273Properties
Properties
Properties274
Properties
OverviewTypical properties include cross-sectional properties of beam elements, thicknesses of plate and shell elements, element integration rules, and hourglass controls. Properties are assigned to the elements of a specified part or element type, either directly to the elements, or indirectly through the part to which the elements belong.
Element Types and Associated Properties
Thin Shell Elements
Two-dimensional elements, commonly referred to as plate and shell elements, are used to represent areas in your model where one of the dimensions is small in comparison to the other two. As shown Figure 1 the thickness is substantially less than dimensions a or b.
Figure 1 Typical Plate Element
ELEMENT_SHELL - General-purpose plate elements (4-noded) capable of carrying in plane force, bending forces, and transverse shear force. The triangular element is defined by repeating the third for the fourth node. This family of elements are the most commonly used shell elements in the SimXpert crash element library. These are the element types generated by the Automesher.
275PropertiesProperties
*SECTION_SHELL - The thin shell elements are commonly referred to as the plate and shell elements within SimXpert. Their properties, are defined using the *SECTION_SHELL entry. The format of the *SECTION_SHELL entry is as follows:
Properties276
Field Contents
SECID Section ID, to be referred by parts
ELFORM Element formulation options
= 1: Hughes-Liu
= 2: Belytscho-Tsay
= 3: BCIZ triangular shell
= 4: C0 triangular shell
= 5: Belytscho-Tsay membrane
= 6: S/R Hughes-Liu
= 8: Belytscho-Leviathan shell
= 9: Fully integrated Belytscho-Tsay membrane
= 10: Belytscho-Wong-Chiang
= 11: Plane stress (x-y plane)
= 12: Fast (co-rotational) Hughes-Liu
= 13: Plane strain (x-y plane)
= 14: Axisymmetric solid (y-axis of symmetry) - area weighted
= 15: Axisymmetric solid (y-axis of symmetry) - volume weighted
= 16: Fully integrated shell element
= 17: Fully integrated DKT triangular shell element
= 18: Fully integrated DK quadrilateral/triangular shell element
= 20: Fully integrated linear assumed strain C0 shell
= 21: Fully integrated linear assumed strain (5 DOF per node) C0 shell
= 22: Linear shear panel element (3 DOF per node)
SHRF Shear correction factor (value of 5/6 is recommended for solid plate)
NIP Number of through thickness integration points
277PropertiesProperties
PROPT Printout options
= 0: Average resultants and fiber lengths
= 1: resultants at plan points and fiber lengths
= 3: Resultants, stresses at all points, fiber lengths
QR Quadrature rule
LT 0.: Absolute value is used as the Quadrature rule
EQ. 0.: Gauss Rule (up to five points permitted)
EQ. 1.: Trapezoidal Rule
ICOMP Flag for orthotropic/anisotropic layered composite material model
= 0: Homogeneous
=1: Composite
SETYP 2D solid element type (defined for ELFORM 13, 14, and 15)
= 1: Lagrangian
= 2: Eulerian (single material with voids)
= 3: ALE
T1 Shell thickness at node 1
T2, T3, T4 Shell thickness at nodes 2, 3, and 4 respectively
NLOC Location of reference surface normal to s axis (Hughes-Liu elements: ELFORM = 1 or 6)
MAREA Nonstructural mass per unit area
IDOF Applies to shell element types 25 and 26.
.EQ. 1(default): The thickness field is continuous across the element edges for metal-forming applications.
.EQ. 2: The thickness field is discontinuous across the element edges. This is necessary for applications such as crashworthiness where shell intersections, sharp included angles, and non-smooth deformations exist.
EDGSET Edge node set, required for shell type seatbelts.
AFAC Smoothing weight factor - simple average (No smoothing if value is -1.)
BFAC Smoothing weight factor - volume weighting
Field Contents
Properties278
The element coordinate systems for the shell element is shown in Figure 2. The orientation of the element coordinate system is determined by the order of the connectivity for the nodes. The element z-axis, often referred to as the positive normal, is determined using the right-hand rule. Therefore, if you change the order of the nodal connectivity, the direction of this positive normal also reverses. This rule is important to remember when applying pressure loads or viewing the untransformed element forces or stresses. Untransformed directional element stress plots may appear strange when they are displayed by the postprocessor in SimXpert because the normals of the adjacent elements may be inconsistent. Remember that components of forces, moments, and element stresses are always output in the element coordinate system.
Figure 2 Thin Shell Element Geometry and Coordinate Systems
See Also:• LS-DYNA Keyword User’s Manual
CFAC Smoothing weight factor - isoparametric
DFAC Smoothing weight factor - equipotential
EFAC Smoothing weight factor - equilibrium
START Start time for smoothing
END End time for smoothing
AAFAC ALE advection factor
DX, DY Normalized dilatation parameters of the kernel function in X and Y directions respectively
ISPLINE Replaces choice for the EFG kernel functions definition in *CONTROL_EFG.
IDILA Replaces choice for the normalized dilation parameter definition in *CONTROL_EFG.
IRID Integration Rule Id (User defined)
Field Contents
279PropertiesProperties
Thick Shell Elements
If the thickness dimension of your component is small, but not too small, in comparison to the other two, dimensions, you can model it with thick shell elements.
Figure 3 Typical Plate Element
*ELEMENT_TSHELL - Eight noded thick shell element useful for modeling thick plated components. Unlike the thin shell element, *ELEMENT_SHELL which represents the plate through the middle surface, and thickness, the 8-noded thick shell element represents plate as a hexahedron, the first four nodes representing the bottom surface, and the last four nodes representing the top surface. The thick
Properties280
shell wedge element is defined by repeating the third for the fourth node, and repeating the seventh for the eighth node.
Figure 4 Thick Shell Element Connectivity
281PropertiesProperties
SECTION_TSHELL
The properties of the thick shell elements are defined using the *SECTION_TSHELL entry. The format of the *SECTION_TSHELL entry is as follows:
Field Contents
SECID Section ID, to be referred by parts
ELFORM Element formulation options
= 1: 1point reduced integration (Default)
= 2: Selective reduced 2X2 in plane integration
= 3: Assumed strain 2X2 in plane integration
SHRF Shear correction factor (a value of 5/6 recommended for solid section plate)
NIP Number of through thickness integration points. (If NIP = 0, the Default value of 2 is used)
PROPT Printout options
= 0: Average resultants and fiber lengths
= 1: resultants at plan points and fiber lengths
= 3: Resultants, stresses at all points, fiber lengths
Properties282
The orientation of the element coordinate system is determined by the order of the connectivity for the nodes. The element z-axis (the thickness direction) often referred to as the positive normal to the face connected by nodes n1, n2, n3, and is determined using the right-hand rule (cross product of edge vectors n1-n2 and n1-n3). Therefore, if you change the order of the nodal connectivity, the direction of this positive normal also reverses. This rule is important to remember when applying pressure loads or viewing the untransformed element forces or stresses. Untransformed directional element stress plots may appear strange when they are displayed by the postprocessor in SimXpert because the normals of the adjacent elements may be inconsistent. Remember that components of forces, moments, and element stresses are always output in the element coordinate system.
See Also:• LS-DYNA Keyword User’s Manual
Three-Dimensional Elements
Whenever you need to model a structure that does not behave as a bar or plate structure under the applied loads, you need to use one or more of the three-dimensional elements. The three-dimensional elements are commonly referred to as solid elements. Typical engineering applications of solid elements include engine blocks, brackets, and gears.
The Solid Elements in the Crash Workspace Include the Following:1. 8 noded hexahedron
2. 6 noded pentahedron (degenerated from the 8-node hexahedron, by repeating node 4 for the last four nodes (n1, n2, n3, n4, n4, n4, n4, n4, n4)
3. 4 noded tetrahedron (degenerated from the 8-node hexahedron, by repeating node 5 for the sixth node, and repeating node 7 for the eighth node (n1, n2, n3, n4, n5, n5, n6, n4, n6)
QR Quadrature rule
LT 0.: Absolute value is used as the Quadrature rule
EQ. 0.: Gauss Rule (up to five points permitted)
EQ. 1.: Trapezoidal Rule
ICOMP Flag for orthotropic/anisotropic layered composite material model
= 0: Homogeneous
=1: Composite
IRID Integration Rule Id (User defined)
B1 Material angle (β1) at first integration point. This angle is measured with respect to the element edge n1-n2.
Field Contents
283PropertiesProperties
4. 10 noded tetrahedron
Figure 5 Solid Elements
Properties284
SECTION_SOLID
The properties of the solid elements are entered on the *SECTION_SOLID form shown below:
Field Contents
Title Unique name identifying the section.
SECID Section ID, to be referred by parts
285PropertiesProperties
ELFORM Element formulation options
= 0: 1 point co-rotational for *MAT_MODIFIED_HONEYCOMB
= 1: Constant stress solid element (Default)
= 2: Fully integrated S/R solid
= 3: Fully integrated quadratic 8 node element with nodal rotations
= 4: S/R quadratic tetrahedron with nodal rotations
= 5: 1 point ALE
= 6: 1 point Eulerian
= 7: 1 point Eulerian ambient
= 8: acoustic
= 9: 1 point co-rotational for *MAT_MODIFIED_HONEYCOMB
= 10: 1 point tetrahedron
= 11: 1 point ALE multi-material element
= 12: 1 point integration with single material and void
= 13: 1 point nodal sure tetrahedron for bulk forming
= 14: 8 point acoustic
= 15: 2 point pentahedron element
= 16: 5 point 10 noded tetrahedron
= 18: 8 point enhanced strain solid element for linear statics only
AET Ambient element type (foe ELFORM = 7, 11 or 12)
= 3: pressure outflow
= 4: pressure inflow (Default for ELFORM = 7)
AFAC Smoothing weight factor - simple average (if value is -1, smoothing turned off)
BFAC Smoothing weight factor - volume weighting
CFAC Smoothing weight factor - isoparametric
Field Contents
Properties286
DFAC Smoothing weight factor - equipotential
START End time for smoothing
END Start time for smoothing
AAFAC ALE advection factor
DX, DY, DZ Normalized dilatation parameters of the kernel function in X, Y, and Z directions respectively
ISPLINE Replaces choice for the EFG kernel functions definition in *CONTROL_EFG..
.EQ. 0: Cubic spline function (default)
.EQ. 1: Quadratic spline function
.EQ. 2: Cubic spline function with cubic shape
IDILA Replaces choice for the normalized dilation parameter definition in *CONTROL_EFG..
.EQ. 0: Maximum distance based on the background elements
.EQ. 1: Maximum distance based on the sourounding nodes
IEBT Essential boundary condition treatment:
.EQ. 1: Full transformation method
.EQ. -1: w/o transformation
.EQ. 2: Mixed transformation method
.EQ. 3: Coupled FEM/EFG method
.EQ. 4: Fast transformation method
.EQ. -4: w/o transformation
.EQ. 5: Fluid particle method for E.O.S and *MAT_ELASTIC_FLUID materials
Field Contents
287PropertiesProperties
See Also:• LS-DYNA Keyword User’s Manual
One-Dimensional Elements
A one-dimensional element is one in which the properties of the element are defined along a line or curve. Typical applications for the one-dimensional element include trusses, beams, and stiffeners. One-
IDIM Domain integration method:
.EQ. 1: Local boundary integration (default)
.EQ. 2: Two-point gauss integration
.EQ. 3: Improved gauss integration for IEBT = 4 or -4
TOLDEF Deformation tolerance for the activation of adaptive EFG Semi-Lagrangian and Eulerian kernel.
= 0.0: Lagrangian kernel
> 0.0: Semi-Lagrangian
<0.0: Eulerian kernel.
Field Contents
Properties288
dimensional elements discussed in this chapter include 3D beams, trusses, 2D axisymmetric shells, and 2D plane strain beam elements.
Figure 6 Beam Elements
SECTION_BEAM
289PropertiesProperties
The properties of the one dimensional elements are entered on the *SECTION_BEAM form shown below:
Field Contents
SECID Section ID, to be referred by parts
ELFORM Element formulation options
= 1: Hughes-Liu with cross section integration (Default)
= 2: Belytscho-Schwer resultant beam
= 3: Truss resultant
= 4: Belytscho-Schwer full cross-section integration
= 5: Belytscho-Schwer tubular beam full cross-section integration
= 6: Discrete beam/cable
= 7: 2D plane strain shell element (xy plane)
SHRF Shear factor (5/6 recommended for rectangular section beam)
Properties290
See Also:• LS-DYNA Keyword User’s Manual
QR Quadrature rule or rule number for user defined integration rule
= 1: 1 point integration
= 2: 2X2 Gauss quadrature (default beam)
= 3: 3X3 Gauss quadrature
= 4: 3X3 Lobatto quadrature
= 5: 4X4 Gauss quadrature
= -n: where the absolute value of n is the number of the user defined rule.
CST Cross section type (Not needed for truss, resultant beam, discrete beam, and cable elements)
= 0: rectangular
= 1 Tubular (circular only)
= 2 Arbitrary (User defined integration rule)
SCOOR Location for triad for tracking the rotation of the discrete beam element
NSM Nonstructural mass per unit length
TS1 Beam thickness (for CST = 0.0, 2.0), or Outer diameter (CST=1.0) in s direction at node 1
TS2 Beam thickness (for CST = 0.0, 2.0), or Outer diameter (CST=1.0) in s direction at node 2
TT1 Beam thickness (for CST = 0.0, 2.0), or Outer diameter (CST=1.0) in t direction at node 1
TT2 Beam thickness (for CST = 0.0, 2.0), or Outer diameter (CST=1.0) in t direction at node 2
NSLOC Location of reference surface normal to s axis (for Hughes-Liu beam elements only)
NTLOC Location of reference surface normal to t axis (for Hughes-Liu beam elements only)
IRID Integration Rule Id (User defined)
Field Contents
291PropertiesProperties
Discrete Elements
Discrete elements in SimXpert Crash comprise of spring and damper elements used between two nodes, or a node and ground.
SECTION_DISCRETE
The properties of the discrete elements are entered on the *SECTION_DISCRETE form shown below:
See Also:• LS-DYNA Keyword User’s Manual
Seatbelt Elements
Seat belt elements are elements with single degree of freedom, connecting two nodes.
Field Contents
SECID Section ID, to be referred by parts
DRO Displacement/Rotation Option:
=0 for translational spring or damper
=1 for torsional spring or damper
KD Dynamic magnification vector
V0 Test velocity
CL Clearance
FD Failure deflection (twist, for DRO = 1. Negative for compression, positive for tension
CDL Deflection (twist, for DRO = 1) limit in compression
TDL Deflection (twist, for DRO = 1) limit in tension
Properties292
SECTION_SEATBELT
The properties of the seat belt elements are entered on the *SECTION_SEATBELT form shown below:
See Also:• LS-DYNA Keyword User’s Manual
Mass Elements
Mass elements are used to defined lumped masses to nodes. In SimXpert crash workspace, the mass associated with the mass elements are assigned directly to the mass element, and hence no properties are needed to be created.
See Also:• LS-DYNA Keyword User’s Manual
Element IntegrationSimXpert crash Workspace normally uses the recommended integration through thickness of beams and shell elements. However, you can use other through-thickness integration rules using
• *INTEGRATION_BEAM for defining through thickness integration rules for the beam elements
• *INTEGRATION_SHELL for defining through thickness integration rules for both the thin and thick shell elements.
See Also:• LS-DYNA Keyword User’s Manual
Field Contents
SECID Section ID, to be referred by parts
293PropertiesProperties
HourglassingThe advantage of the reduced integration elements is that the strains and stresses are calculated at the location that provide optimal accuracy, the so-called Barlow points. The reduced integration elements also tend to underestimate the stiffness of the element which often gives better results in a typically overly-stiff finite element analysis displacement method. An additional advantage is that the reduced number of integration points decreases CPU time and storage requirements. The disadvantage is that the reduced integration procedure may admit deformation modes that cause no straining at the integration points. These zero-energy modes cause a phenomenon called “hourglassing,” where the zero energy mode starts propagating through the mesh, leading to inaccurate solutions. This problem is particularly severe in first-order quadrilaterals and hexahedrals. To prevent these excessive deformations, an additional artificial stiffness is added to these elements. In this so-called hourglass control procedure, a small artificial stiffness is associated with the zero-energy modes. This procedure is used in many of the solid and shell elements in SimXpert crash Workspace Use the *HOURGLASS keyword data to define hourglass and bulk viscosity properties which are referenced via the HGID in the *part command..
Figure 7 Hourglassing
See Also:• LS-DYNA Keyword User’s Manual
Properties294
293Meshing and Element Creation
Meshing and Element Creation
Meshing and Element Creation294
Meshing and Element Creation
Modeling GuidelinesFinite element modeling in many ways is more like an art than a science since the quality of the results is dependent upon the quality of your model. One of the more common errors that a beginning finite element analyst makes in modeling is to simply simulate the geometry rather than to simulate both the geometry and the physical behavior of the real structure. The following modeling guidelines are provided to put a little more science back into the art of finite element modeling:
• Choosing the right element.
• Mesh transitions.
The above guidelines are by no means complete; however, they do serve as a good starting point. There is no better substitute for good modeling than experience. It is also good modeling practice to simulate and validate a new capability or a feature that you have not used before with a small prototype model before applying this feature to your production model. Model verification techniques are covered in Quality Checks, 297.
SimXpert contains a large library of structural elements. In many situations several elements are capable of modeling the same structural effects. The criteria for the selection of an element may include its capabilities (for example, whether it supports anisotropic material properties), the amount of time required to run an analysis (in general, the more DOF an element has, the longer it runs), and/or its accuracy.
In many cases the choice of the best element for a particular application may not be obvious. For example, in the model of a space frame, you may choose to use truss elements if bending or torsional stiffness is unimportant or to use the beam elements with axial, bending and torsional stiffness. You may even choose to represent the members with built-up assemblies of plate or solid elements. The choice of which type and number of elements to use depends primarily on your assessment of the effects that are important to represent in your model and on the speed and accuracy you are willing to accept.
In this context, it is critical that you have a fairly good idea of how the structure will behave prior to generating your finite element model. The best source of such insight is usually experience with similar structures or components. In other words, understanding the load path is crucial in the selection of the appropriate element. In addition, a few hand calculations can usually provide a rough estimate of stress intensities. Such calculations are always recommended. If you do not have a fairly good idea of how the structure will behave, you may be misled by incorrect results due to errors or incorrect assumptions in your input data preparation.
The following guidelines are provided to help you in selecting the “right” element for your task.
295Meshing and Element CreationMeshing and Element Creation
Avoid highly skewed elements (see Figure 1). The angle should be as close to 90 degrees as possible.
Figure 1 Highly Skewed Element
Aspect ratio is defined as (length/width). Very high aspect ratio (see Figure 2) should also be avoided in areas where there is a high stress gradient.
Figure 2 Element with High Aspect Ratio
Warping is a measure of the amount the element deviates from being planar (see Figure 3). Element warping should be minimized.
Figure 3 Highly Warped Element
Mesh Transitions
Mesh transition can be a complicated subject. It may simply be used to refine the mesh in a particular area, connect different element types (for example, a CBAR element to a solid element), or provide transitions required to model the geometry of the structure. Two guidelines for mesh transitions are as follows:
1. Never place a mesh transition in an area of interest or in an area where there is a large variation in stress.
2. Mesh transitions should be located away from the areas of interest in a region.
α
α
l ω⁄
l
ω
Element Mid-Plane
Meshing and Element Creation296
Due to incompatibilities between finite element types, any transition between different element types (even a transition from quadrilateral to a triangular elements) can result in local stress anomalies. Normally, these stress anomalies are localized and dissipate quickly as you move away from the transition. However, a problem arises when the transition occurs in an area of interest. In this case, the local stress rises (or decreases) due to the effect of the transition; in other words, the results may be conservative (or non-conservative) in an area near a transition. However, if this localized stress variation occurs away from areas of interest, the increase (or decrease) in stress caused by the transition should cause no concern.
• Transition from a Coarse Mesh to a Fine Mesh
The transition from a coarse mesh to a fine mesh, or vice versa, may not always be an easy task. One common method of performing a transition is to use an intermediate belt of triangular elements as shown in Figure 4.
Figure 4 Mesh Transition
Mesh ControlBefore you create elements, you should first specify a default mesh size by selecting Element Options from the Elements menu. Mesh sizes can also be set interactively using Mesh Size from the Elements menu. In addition you can also define hard points on curves or surfaces to ensure that a node is placed at that location. You do this using Create Hard Points from the Geometry menu. Mesh should have high density in areas of large stress gradients.
Meshing
Automeshing
You can use the selections under Automeshing to create multiple elements on geometry.
• Automesh - Used to create quadrilateral and triangular plate/shell elements on surfaces.
• Solid Mesher - Used to create a tetrahedral mesh inside bounding surfaces
• Interactive Mesh Size - Interactively modifies the number of elements along a selected curve
Q4 Q4
Q4 Q4
Q4 Q4
Q4 Q4
Q4
Q4
T3
T3
T3
T3
T3
T3
297Meshing and Element CreationMeshing and Element Creation
Manual Meshing
You can use the selections under Manual Meshing to create mesh without having surfaces.
• 2-3-4 Line Mesh - Creates a mapped mesh by selecting 2,3, or 4 bounding curves. User can modify the number of elements to be created on each curve. Set or modify the mesh elements parameters using Params button from the pick menu.
• 3-4 Point Mesh - Creates mesh between the 3 or 4 selected points. You can specify the number of elements to be created between each pair of selected points. Points should be selected in a circular manner.
• Drag Mesh - Creates a solid or shell mesh by dragging elements or nodes along a specified vector or curve.
• Flange Creation - Creates a flange by dragging selected nodes through a specified width and angle.
• Linear Solid Mesh - Creates solid elements between two groups of shell elements.
• Refine Mesh - Refines the selected mesh region to specified edge length, while maintaining element connectivity with congruent elements.
• Spin Mesh - Creates solid or shell elements by rotating shell elements or nodes through a specified angle about a vector.
Merge Coincident NodesNodes along common edges of adjoining geometry entities need to match. If these nodes are not coincident, your model will have free edges or faces at these points. Always merge coincident nodes before analyzing your model using Merge Coincident Nodes from the Node menu.
Quality Checks
Free Edges
You can check that your model has completed merging coincident nodes by displaying free edges in your model. In Figure 5 the model is shown with free edges displayed by selecting Highlight FE Boundary from the View menu.The picture on the left shows the model with a solid horizontal line running through the middle. This indicates that a free edge exists there and the top and bottom are not connected. The
Meshing and Element Creation298
picture on the right shows the model after the coincident nodes have been merged. The model is now one continuos piece.I
Figure 5 Free Edge Check - Before and After Merge Coincident Nodes
Consistent Plate Normals
You can check the orientation of your plate elements using the Normals selection from the Element menu. When the pick box appears, in the Mode list, click Show Normal then click All. In Figure 6 you can see that these elements do not have consistent normals.
Figure 6 Inconsistent Normals
Free (unconnected) edge
Before After
299Meshing and Element CreationMeshing and Element Creation
You can enforce consistent normals by now clicking Fix Normal in the Mode list and then selecting a reference element with the desired normal direction. You could also click Rev. Normal and then select the elements on which to reverse normals.
Figure 7 Consistent Normals
To turn off the display of normal vectors click Hide Normal in the Mode list then click All.
Element Shape Checks
The types of quality checks that SimXpert can perform on shell elements can be seen on the following form. It is accessed by selecting Quality/Quality from the Elements menu.
• Warp check: Evaluates how far out of plane the element ‘bends’. Warp is computed by determining the angle between the normals of 2 triangular regions superimposed on the element. This check is also applicable to quad faces of solid elements.
• Taper check: Compares the ratios of the lengths of opposite edges of an element.
• Skew check: Compares the maximum angles between the element diagonals.
Meshing and Element Creation300
• Interior Angle check: Evaluates the interior angles measured at each of the four (or 3) corner nodes.
If any element exceeds minimum or maximum tolerance levels specified for an element check, it is considered to have failed that test.
SimXpert can compute a Quality Index which is a weighted composite of all the selected quality checks. You can toggle the display of the Quality Index from the Bottom Block by selecting Fringes On/Off from the FE-Grafix menu.
Elements that violate any of the activated quality criteria will be displayed in magenta.
Those elements color-coded red to orange have marginal quality. You can further investigate which specific tests your elements may be failing by selecting the individual quality measure from the FE-Qual
301Meshing and Element CreationMeshing and Element Creation
menu and your display will update accordingly. The following image shows the model now color-coded based on Warpage.
Once again, failed elements are shown in magenta. Elements with a high value that does not exceed the threshold are color-coded red or orange.
Tools to Help Fix Poorly Shaped Elements• Manual - Element / Quality / Manual Fix - allows you to select a node and drag it to a new
location. Element color coding will change in real time to feed back how the element’s quality is changing. Click the middle mouse button to finalize the new nodal location.
Meshing and Element Creation302
• Mesh Quality - Element / Quality / Quick Quality - allows you to select elements for mesh quality enhancement then select desired parameters as shown below:
• Fast Shell Enhancing attempts to fix failed elements only. Once they pass all selected criteria, no further enhancement is attempted.
• Slow Shell Enhancing attempts to fix failed elements and also to further improve all selected elements.
• All passes except Warp Enhancing will maintain nodes on the FE-Surface.
Warp Enhancing will move the node (within the specified tolerance) normal to the surface to decrease the warping.
303Loads and Boundary Conditions
Loads and Boundary Conditions
Loads and Boundary Conditions304
Loads and Boundary ConditionsThis chapter describes the loads and boundary conditions available when performing analysis with the SimXpert crash workspace. Each of the load types discussed may be applied to your model individually, or in any combination.
Supported Load and Constraint TypesMost often, boundary conditions are imposed in the form of constraints on selected degrees of freedom on the model. Typically, several degrees of freedom are constrained to ground, using Single Point Constraints (SPC) boundary conditions.
Besides single-point constraints, crash workspace provides a method of creating linear constraint relationships between several degrees of freedom.
A third type of boundary conditions is the contact boundary condition for specifying that certain regions of the structure might be touching or separating during the simulation process. Contact boundary condition is an important feature of the crash workspace.
This section discusses the single-point and multiple-point constraints. The rigid elements are discussed under Meshing, and the Contact is discussed under the section on contact.
Single-Point Constraints
A Single-Point Constraint (SPC) is a constraint that is applied to a single degree of freedom, which may be either a component of motion at a node or the displacement of a scalar point.
The primary applications for single-point constraints are:
1. To tie a structure to ground.
2. To apply symmetric or anti symmetric boundary conditions by restraining the degrees of freedom that must have a zero value to satisfy symmetry or anti symmetry. Symmetry is discussed in the Modeling Guide.
3. To remove degrees of freedom that are not used in the structural analysis (that is, are not connected to any structural elements or otherwise joined to the structure).
SPC BC• *BOUNDARY_SPC constraints usually specified at model boundaries to define rigid support
points. These can also be used to apply an enforced nonzero displacement. Directions are in the applicable nodal coordinate system.
305Loads and Boundary ConditionsLoads and Boundary Conditions
• *CONSTRAINED_LINEAR_OPTION defines linear constraint equation between displacements and rotations defined in global (OPTION =GLOBAL), or local (OPTION =LOCAL) coordinate system. The constraint equation is generally of the form:
where uk are the displacements/rotations, and Ck are the user defined coefficients.
Nodal BC• FORCE and MOMENT -- Concentrated forces and moments, which are applied directly to
nodes. The magnitude is entered directly. The direction is defined by selecting an appropriate degree-of-freedom (DOF) code. The node or nodes to which forces or moments are to be applied, can be selected directly or via node set. Follower forces and moments can also be applied. The temporal variation of the force or moment can be defined by using a load versus time curve (LCID).
• Boundary Sliding Plane -- Boundary conditions at nodes on symmetry planes defined by creating the symmetry plane.
• Boundary Temperature -- Temperature Boundary Conditions at nodes for thermal loading, or temperature dependent materials.
• Initial Temperature -- Defines initial nodal temperatures. These can be applied either directly to the nodes, or via node set.
• Initial Foam Reference Geometry -- Defines reference configuration for the geometry of the foam material for initialization of stresses in the foam.
• Boundary Prescribed Motion -- Defines imposed (nonzero) nodal motion (velocity, acceleration, or displacement) on nodes, node sets, or rigid bodies.
Element BC• Load Shell -- Distributed pressure load applied to shell or thick shell elements, or element set.
• Load Beam -- Distributed traction load along any local axis of beam elements or a set of beams.
• Initial Strain Shell -- Applies initial strains to shell elements.
• Initial Stress Shell -- Applies initial stresses to shell elements.
• Initial Stress Beam-- Applies initial stresses to beam elements.
• Initial Stress Solid -- Applies initial stresses to solid elements.
• Initial Volume Fraction -- Defines initial volume fraction for different materials in multi-material ALE, or in single material and void models.
• Initial Momentum -- Defines initial momentum for depositing in solid elements, to simulate impulse loading.
01
CuC k
n
kk =
=
Loads and Boundary Conditions306
Load Segment • Applies distributed pressure load over a triangular or quadrilateral segment defined by four
nodes, over each segment in a segment set.
Global BC• BOUNDARY_CYCLIC -- Defines nodes in boundary planes for cyclic symmetry
• BOUNDARY_PRESCRIBED_MOTION -- Defines imposed (nonzero) nodal motion (velocity, acceleration, or displacement) on nodes, node sets, or rigid bodies.
• CONSTRAINED_ADAPTIVITY -- Defines adaptive constraints to constrain nodes to the midpoint along edges of shell elements.
• CONSTRAINED_GENERALIZED_WELD_BUTT -- Defines butt welds. Weld failures include both plastic and brittle failures. Coincident nodes are permitted, provided local coordinates are defined.
• CONSTRAINED_EULER_IN_EULER -- Defines coupling between materials in two overlapping, and geometrically identical multi-materials Eulerian mesh sets. It also allows frictional contact between two or more Eulerian materials.
• CONSTRAINED_GLOBAL -- Defines a global boundary constraint plane
• CONSTRAINED_INTERPOLATION -- Defines an interpolation constraint whereby the motion of a single dependent node is interpolated from the motion of a set of independent nodes.
• CONSTRAINED_POINTS -- Defines constraint between two points with the specified coordinates connecting two shell elements at locations other than nodal points.
• CONSTRAINED_RIGID_BODIES -- Defines rigid body stoppers, to conveniently control the motion of rigid tooling in metal forming applications.
• CONSTRAINED_RIGID_BODY_STOPPERS -- Defines the merger of two rigid bodies
• CONSTRAINED_SHELL_TO_SOLID -- Defines a tie (constraint) between the edge of a shell and solid elements.
• CONSTRAINED_TIE_BREAK -- Defines a tie (constraint) between the edge of a shell and solid elements enabling local release as a function of plastic strain at the shell elements surrounding the interface nodes.
• CONSTRAINED_TIED_NODES_FAILURE -- Defines a tied (constrained) node set with failure based on plastic strains.
• CONSTRAINED_JOINT_STIFFNESS -- Defines translational and rotational joint stiffness. Options include FLEXION-TORSION, GENERALIZED, and, TRANSLATIONAL.
• INITIAL_DETONATION -- Defines points to initiate high explosive detonations in parts
• INITIAL_GAS_MIXTURE -- Defines initial temperature and density of different gas species in *MAT_GAS_MIXTURE for the simulation of gas mixtures.
• INITIAL_VELOCITY -- Defines initial nodal velocities using node set IDs.
• INITIAL_VEHICLE_KINEMATICS -- Defines initial kinematical information such as orientation, yaw, pitch, and roll axes for a vehicle.
307Loads and Boundary ConditionsLoads and Boundary Conditions
• INITIAL_VELOCITY_RIGID_BODY -- Defines the initial translational and rotational velocities at the center of gravity for a rigid body. This input overrides all other velocity input for the rigid body and the nodes which define the rigid body.
• INITIAL_VELOCITY_GENERATION -- Defines initial velocity for rotating and translating bodies.
• INITIAL_VOID -- Defines initial voided part set or part numbers.
• INITIAL_VOLUME_FRAC_GEOMETRY-- Defines initial volume fraction of different materials in multi-material ALE, or in single material and void models.
• Load Blast-- Defines an airblast function for the application of pressure loads due to explosives in conventional weapons.
• Load Body-- Defines body force loads due to prescribed base acceleration or angular velocity using global axes definition. This load applies to all nodes in the model unless a part subset is specified via the *LOAD_BODY_PARTS keyword.
• Load Body Generalized-- Defines body force loads due to prescribed base acceleration, or a prescribed angular velocity over a subset of the model. The subset is defined by using nodes.
• Load Body Parts-- Defines body force loads for nodes belonging to selected parts.
• Load Brode-- Defines brode function for application of pressure loads due to explosives.
• Load Density Depth -- Defines density versus depth for gravity loading for analyzing submerged and underground structures.
• Load Mask-- Defines distributed pressure load over a three dimensional shell part. The pressure is applied to a subset of elements that lie within a fixed global box and lie either outside or inside of a closed curve in space which is projected onto the surface.
• Load Rigid Body-- Defines concentrated nodal force to a rigid body. The force is applied at the center of mass, or a moment is applied around a global or local axis.
• Load SSA-- Defines a simple way of loading the structure to account for the effects of primary explosion and the subsequent bubble oscillations.
• Load SuperPlastic Form -- Defines loads for superplastic forming analysis.
• Load Thermal Constant-- Defines nodal temperatures that remains constant (during the duration of the analysis) or thermally loading a structure for structural analysis.
• Load Thermal Load Curve -- Defines uniform (throughout the model) nodal temperatures that can vary (in time) according to a load curve.
• Load Thermal Variable -- Defines nodal sets giving the temperature that varies during the duration of the analysis.
• Airbag - Defines an airbag or control volume, providing a way of defining the thermodynamic behavior of the gas flow into the airbag, and a reference configuration for the fully inflated bag. The available thermodynamic relationships include: Simple Pressure Volume, Simple Airbag Model, Adiabatic Gas Model, Wang Nefske, Wang Nefske Jetting, Wang Nefske Multiple Jetting, Load Curve, Linear Fluid, Hybrid, Hybrid Jetting, and Hybrid Chemkin.
• Airbag Interaction -- Defines two connected airbags which vent into each other.
Loads and Boundary Conditions308
• Airbag Reference Geometry -- Defines airbag reference geometry
LBC SetsLoads and boundary conditions can be grouped into sets. The applied loads can be applied independently or in combination.
To group your applied loads into load sets select Create LBC Set from the BC menu.
Supply a name for your LBC set, then select the desired loads and boundary conditions.
309Contact
Contact
Contact310
Contact
OverviewThe simulation of many physical problems requires the ability to model the contact phenomena. This includes analysis of interference fits, rubber seals, tires, crash, and manufacturing processes among others. The analysis of contact behavior is complex because of the requirement to accurately track the motion of multiple geometric bodies, and the motion due to the interaction of these bodies after contact occurs or breaks. This includes representing the friction between surfaces and heat transfer between the bodies if required. The numerical objective is to detect the motion of the bodies, apply a constraint to avoid penetration, and apply appropriate boundary conditions to simulate the frictional behavior and heat transfer. This section gives an overview of the methods used in the SimXpert crash Workspace for handling contact.
Contact problems can be classified as one of the following types of contact.
• Deformable-Deformable contact between single (self-contact), or multiple two- and three-dimensional deformable bodies.
• Rigid - Deformable contact between a deformable body and a rigid body, for two- or three-dimensional cases.
• Tied contact in two and three dimensions. This is a general capability for tying (bonding) two deformable bodies, or a deformable body and a rigid body, to each other.
Contact problems involve a variety of different geometric and kinematic situations. Some contact problems involve small relative sliding between the contacting surfaces, while others involve large sliding. Some contact problems involve contact over large areas, while others involve contact between discrete points. The approach adopted by SimXpert crash Workspace to model contact can be used to handle most contact problems.
Contact MethodologyThis section gives an overview of the methods used in the SimXpert crash Workspace for handling contact.
Constraint Method
One side of the contact interface is called the slave side, and the other is designated as the master side. Nodes lying in those surfaces are respectively referred to as the slave nodes and the master nodes. Constraints are imposed on the global equations by a transformation of the displacement components of the slave nodes along the contact interface. To keep the efficiency of the explicit time integration scheme, the mass is lumped to the extent that only the global degrees of freedom of each master node are lumped. Impact and release conditions are imposed to ensure the conservation of momentum.
If the mesh in the master surface zone is finer than the slave surface zone, master nodes can penetrate through the slave surface without resistance, and create incorrect solution, especially if the interface pressures are too high. Better choice of master and slave zoning would minimize such errors in some
311ContactContact
cases. However, in some modeling situations (e.g. modeling of airbags in automotive crash applications) good zoning in the initial configuration may be poor zoning later as the deformation progresses.
Penalty Method
The penalty method places normal interface springs between all penetrating nodes and the contact surface. Momentum is conserved exactly without the necessity of imposing impact and release conditions. Currently there are three formulations of the penalty algorithm.
Standard Penalty Formulation: In this formulation, the interface stiffness is chosen to be approximately of the same order of magnitude as the stiffness of the interface element normal to the interface. If interface pressures become large, unacceptable penetration may occur. The usual remedy of scaling up the penalty stiffness, and scaling down the time step size increase the cost of the simulation.
Soft Constraint Penalty Formulation: In this formulation, in addition to the master and slave contact stiffness, an additional stiffness (called the stability contact stiffness) which is based on the stability (Courant’s criterion) of the local system comprised of two masses (segments) connected by a spring is added. The stability contact stiffness kcs is calculated as:
kcs = 0.5. SOFSCL. m*. (1/(Δtc(t))
where, SOFSCL is the Soft Constraint Penalty Scale factor, m* is a function of the mass of the slave node and the master nodes, and Δtc is set to the initial solution time step.
Segment-based Penalty Formulation: This formulation uses a slave segment-master segment approach instead of the slave node-master segment approach. It is especially very efficient for airbag self-contact during inflation and complex contact conditions.
Accounting for Shell Thickness
Shell thickness effects as well as change in thicknesses are accounted for in the crash Workspace.
Contact Damping
Viscous contact damping can be added to all contact options including single surface contact. It allows to damp out oscillations normal to the contact surfaces during metal forming operations, and it also works effectively in removing high frequency noise in problems involving impact.
Friction
Friction in crash Workspace is based on a Coulomb formulation
See “LS-DYNA Theory Manual” for a complete description of the friction formulation.
Contact312
Tied Contact
Tied contact or tied interfaces provides a convenient way of modeling with dissimilar (non congruent) meshes across an interface. This can often decrease the amount of effort required to generate meshes since it eliminates the need to match nodes across common faces of parts.
Contact Types
Different types of contact may be defined in SimXpert crash. Some of the most common contact types are listed here. Refer to the “LS-DYNA Keyword User’s Manual” for a more complete and detailed description.
• Automatic Nodes to Surface
• Automatic Single Surface
• Automatic One way Surface to Surface
• Automatic Surface to Surface
• Nodes to Surface
• Surface to Surface
• Tied Nodes to Surface
313ContactContact
• Tied Shell Edge to Surface
• Tied Surface to Surface
• Airbag Single Surface
• Rigidwall Geometric Flat
• Rigidwall Geometric Cylinder
• Rigidwall Geometric Sphere
Contact Parameters
A list of the most common contact parameters are described here. Refer to the “LS-DYNA Keyword User’s Manual” for a more complete and detailed description.
Variable Description
FS Static coefficient of friction
FD Dynamic coefficient of friction
DC Exponential decay coefficient
VC Coefficient for viscous friction
VDC Viscous damping coefficient in percent critical
PENCHK Small penetration option in contact search.
BT Birth time of contact (contact surface becomes active at this time)
DT Death time of contact (contact surface is deactivated at this time)
SFS Scale factor on default slave penalty stiffness.
SFM Scale factor on default master penalty stiffness
SST Optional thickness for slave surface (overrides true thickness)
MST Optional thickness for master surface (overrides true thickness)
SFST Scale factor for slave thickness (scales true thickness)
SFMT Scale factor for master thickness (scales true thickness)
FSF Coulomb friction scale factor
vs.F Viscous friction scale factor
CF Thermal conductivity of fluid between the slide surfaces
FRAD Radiation factor between the slide surfaces
HTC Heat Transfer conductance for close gaps
GCRIT Critical gap. Use Heat Transfer conductance defined (HTC) for gap thickness less than the value of GCRIT
GMAX No thermal contact if gap is greater than GMAX
Contact314
CD_FAC A multiplier used on the element characteristic distance for the search algorithm.
SOFSCL Scale factor for constraint forces of soft constraint option
LCIDAB Load Curve Id defining thickness of airbag (used in airbag contacts)
MAXPAR Maximum parametric coordinate in segment search.
EDGE Edge to edge penetration check
DEPTH Option to search depth in automatic contact
BSORT Number of cycles between bucket sorts
FRCFRQ Number of cycles between contact force updates for penalty contact formulations
PENMAX Maximum penetration distance
THKOPT Thickness option
SHLTHK Shell thickness option
SNLOG Option to enable/disable shooting node logic in thickness offset contact
ISYMB Symmetric plane option (set to 1, to retain the correct boundary conditions in models with symmetry.)
I2D3D Segment searching option
SLDTHK Solid element thickness (a nonzero positive value activates the contact thickness offsets in the contact algorithm where offsets apply)
SLDSTF Solid element stiffness (a nonzero positive value overrides the bulk modulus taken from the material model referenced by the solid element)
IGAP Flag to improve implicit convergence behavior at the expense of creating some sticking, if parts attempt to separate
IGNORE Option to allow/ignore initial penetrations
trackpen Flag for initial penetration compensation
bucket Bucket sorting frequency
lcbucket Load Curve Id defining bucket sorting frequency vs. time
nseg2trac Number of segments to track for each slave node
initiator Number of iterations for initial penetration checking
Variable Description
315Simulation
Simulation
Time Step Control316
Time Step ControlDuring the solution a new time step is estimated by taking the minimum value over all the elements in the model:
where, N is the number of elements, and a is the scale factor.
For stability reasons the scale factor a is typically set to a value of 0.90 (default) or smaller.
Time Step for Solid Elements
A critical time step size, Δte, is computed for solid elements from:
where, c is the adiabatic speed of sound, Q is a function of the bulk viscosity coefficients C0 and C1.
For elastic materials with a constant bulk modulus c can be computed as:
where, E, ν, and ρ are respectively the Young’s modulus, Poisson’s ratio, and density.
where, Le is a characteristic length calculated as the minimum altitude (for 4-node tetrahedrons), or the
ratio of the element volume to the area of the largest face (for 8-node hexahedra)
Time Step for Shell Elements
For the shell elements, the time step size is given by:
{ }11 2 3min , , ,...,n
Nt a t t t t+Δ = ⋅ Δ Δ Δ Δ
( ){ }1/ 22 2
ee
Lt
Q Q cΔ =
+ +
( )( )( )
1
1 1 2
Ec
υυ υ ρ
−=
+ −
1 0 0
0 0e kk kk
kk
C c C L forQ
for
ε εε
+ <= ≥
se
Lt
cΔ =
317SimulationTime Step Control
where, Ls is the characteristic length, and c is the speed of sound:
Three user options exist for selecting the characteristic length Ls.
In the first (default) option, Ls is given by:
e
where, β = 0 for quadrilateral, and 1 for triangular shell elements, As is the area, and Li (i = 1, 2, 3, 4) is the length of the sides defining the shell elements.
In the second option, the following more conservative value is used for Ls:
where, Di (i = 1, 2) is the length of the diagonals.
The third option, which provides the largest time step size, and is often used for triangular shell elements with very small altitudes uses the following expression for Ls:
Time Step for Beam and Truss Elements
For the Hughes-Liu beam and truss elements, the time step size is given by:
( )21
Ec
ρ ν=
−
( )( )1 2 3 4
1
max( , , , 1 )s
s
AL
L L L L
ββ
+=
−
( )1 2
1
max( , )s
s
AL
D D
β+=
( ) 201 2 3 4
1 2 3 4
1max , min( , , , 10 )
max( , , , (1 ) )s
s
AL L L L L
L L L L
ββ
β+
= + −
e
Lt
cΔ =
Time Step Control318
where, L is the length of the element, an c is the speed of sound calculated as:
The Belytscho beam also uses smaller of the values given by:
and
where, I and A are the maximum value of the moment of inertia, and the area of the beam cross section respectively.
Time Step for Discrete Elements
For spring elements there is no wave propagation speed c to calculate the critical time step size.
However, based on the maximum eigenvalue of the spring with the nodal masses M1, M2 attached to the nodes connected to the spring, the critical time step size can be computed as:
Ec
ρ=
e
Lt
cΔ =
2 2
.5
3 13
12
e
Lt
c II AL AL
Δ = + +
( )1 2
1 2
22e
M Mt
k M MΔ =
+
319SimulationOutput Control
Output ControlThe Control and the database options are used to set solution and output options for the analysis.
Control320
ControlThe Control options are used to set solution options such as analysis duration (*CONTROL_TERMINATION), adaptive meshing (*CONTROL_ADAPTIVE), parallel processing (*CONTROL_PARALLEL), and output options such as energy (*CONTROL_ENERGY), output interval (*CONTROL_OUTPUT). Refer to the LS-DYNA Keyword user’s Manual for a complete list of the Control cards and options. These control options can be set, and or changed from the SimXpert crash Workspace. Many of these options have default settings which work pretty well in most situations. However, a set of standard or user selected control options can be imported from an existing LS-DYNA keyword file, for use either on an as-is basis, or to be selectively modified in the crash workspace GUI.
DatabaseThe LS-DYNA Database options define options for output files containing results information for post processing. For example, the use of the *DATABASE_BINARY_D3_PLOT card lets you select the time interval (DT) between output for the d3plot files. Refer to the “LS-DYNA Keyword User’s Manual” for a complete list of the database cards and options. These database options can be set, and or changed from the SimXpert crash Workspace. Many of these options have default settings which work pretty well in most situations. However, a set of standard or user selected control options can be imported from an existing LS-DYNA keyword file, for use either on an as-is basis, or to be selectively modified in the crash workspace GUI.
321SimulationPerform the Simulation
Perform the SimulationTo perform the analysis, export an LS-DYNA keyword file (File -> Export -> Dyna Model). This will create a keyword input file which can then be used to perform the simulation with LS-DYNA on a computer where it is installed.
Manually Invoking LS-DYNAAs a part of SimXpert Installation, the LS-DYNA Analysis Code solver is installed in a subdirectory under the main installation directory and can be invoked directly. Should you need to manually invoke LS-DYNA, run the executable found under the SimXpert installation directory.
To invoke LS-DYNA from Linux32:
<INSTALLROOT>/Nastran/md2009/dyna/linux32/run_dytran jid=jobid.key iam=simxcr
From Linux64:
<INSTALLROOT>/Nastran/md2009/dyna/linux64/run_dytran jid=jobid.key iam=simxcr
From Windows32:
<INSTALLROOT>/Nastran/md2009/dyna/win32/run_dytran jid=jobid.key iam=simxcr
From Windows64:
<INSTALLROOT>/Nastran/md2009/dyna/win64/run_dytran jid=jobid.key iam=simxcr
where jobid.key is a LSDYNA input deck.
For Linux32, the default INSTALLROOT Path for SimXpert R4 is /msc/SimXpert/R4
For Linux64, the default INSTALLROOT Path for SimXpert R4 is /msc/SimXpert_x64/R4
For Windows32/64, the default INSTALLROOT Path for SimXpert R4 is C:\MSC.Software\SimXpert\R4
Perform the Simulation322
323Example - Crushing of a Thin Square Tube
Example - Crushing of a Thin Square Tube
Crushing of a Thin Square Tube324
Crushing of a Thin Square TubeProblem Description
A square cross section thin tube is to be simulated for crushing by a rigid wall moving with an initial velocity toward one end of the tube, while the other end is fixed. The basic FEA model containing the nodes and the elements is imported from a Nastran input file. Complete the crush model with materials, sections, boundary conditions, loads, and analysis and output options for performing the crush simulation.
Some Key Data:
Cross-section of the tube: 69.954 mm X 69.954 mm
Length of the tube: 320 mm
Thickness of the tube: 1.2 mm
Weight of the rigid wall: 0.4 ton
Initial velocity of the rigid wall: 5646 mm/sec
Steps:
Following are the steps to complete the crush model.
1. Launch SimXpert
Select Structures as the Workspace
2. Select the Solver Card as the GUI Options
Tools -> Options -> GUI Options
Select Solver Card
Click Apply
3. Set the Units for the model
Click Units Manager
Click Standard Units
Select mm, t, s as the units for Length, Mass, and Time respectively
Click OK
Click OK
325Example - Crushing of a Thin Square TubeCrushing of a Thin Square Tube
4. Import the FEA mesh from a MSC.Nastran input file
File -> Input -> Nastran ...
Select the file, square_tube_nast.bdf
Hint: You can find the above file in the PartFiles folder under the help folder in the SimXpert installation directory.
Click Open
Close the (pop-up) Notepad window (nastran.err - Notepad)
The imported FEA mesh represents a quarter model of the thin square tube.
Figure 1 Quarter model of a square section tube
5. Switch the workspace to crash:
Set workspace to crash
6. Create the material:
Materials and Properties-> MAT [1 to 20] -> [003]MAT_PLASTIC_KINEMATIC
Enter steel as the Title for the material
Enter value for RO: 7.85E-9
Crushing of a Thin Square Tube326
Enter value for E: 1.994E5
Enter value for PR: 0.30
Enter value for SIGY: 3.366E2
Enter value for ETAN: 1
Enter value for BETA: 1
Click OK
7. Create properties for the shell elements:
Materials and Properties-> Section -> SECTION_SHELL
Select 2 for ELFORM
Enter value for SHRF: 1.
Enter value for NIP: 3
Note: Hit the Enter key, after typing 3 for NIP. Otherwise, the change will not be made.
Enter value for T1: 1.2
Enter value for T2: 1.2
Enter value for T3: 1.2
Enter value for T4: 1.2
Click OK
8. Assign property and material to the part:
Right click on the (part) PSHELL... in the Model Browser
Click Properties on the pop-up window
Double click on the SECID data box, and click Select
Select SECTION_SHELL_1 from the Select a PSECTION form
Click OK
Double click on the cell below MID, and click Select
Select steel from the Select a Material form
Click OK
Set the value for ADPOPT to 1
Click Modify
Click Exit
9. Create the boundary conditions for the tube:
327Example - Crushing of a Thin Square TubeCrushing of a Thin Square Tube
LBCs -> LBC -> SPC -> Boundary SPC
Make sure all six DOFs are checked-in (selected)
Click Store
Click Exit
Pick all the nodes on the bottom of the tube
Click Done on the Pick panel
This fixes the bottom edge of the tube against all translations and rotations.
Crushing of a Thin Square Tube328
Figure 2 Boundary conditions for the tube model
Top edge
Bottom edge (fixed)
z-symmetry edge
x-symmetryedge
329Example - Crushing of a Thin Square TubeCrushing of a Thin Square Tube
LBCs -> LBC -> SPC -> Boundary SPC
Check in DOFX, DOFRY, DOFRZ
Click Store
Click Exit
Pick all the nodes on the x-symmetry edge, except the node on the bottom edge.
Click Done on the Pick panel
This imposes the symmetric boundary condition on the x-symmetry edge.
LBCs -> LBC -> SPC -> Boundary SPC
Check in DOFZ, DOFRX, DOFRY
Click Store
Click Exit
Pick all the nodes on the z-symmetry edge, except the node on the bottom edge.
Click Done on the Pick panel
This imposes the symmetric boundary condition on the z-symmetry edge.
10. Create a constrained node set on all the nodes on the top edge:
Nodes/Elements ->Elements -> Create -> Rigid -> Constrained Node Set
Set DOF to 2
Click Store
Click Exit
Pick all the nodes on the top edge
Click Done on the Pick panel
11. Create mass elements to represent the rigid wall:
Elements -> Create -> 1 Noded -> Element Mass
Enter value for MASS: 0.01
Click Store
Click Exit
Pick all the nodes on the top edge, except two nodes where the symmetry edges meet the top edge.
Click Done on the Pick panel
Crushing of a Thin Square Tube330
Elements -> Create -> 1 Noded -> Element Mass
Enter value for MASS: 0.005
Click Store
Click Exit
Pick the two nodes where the symmetry edges meet the top edge
Click Done on the Pick panel
12. Create the initial velocity on the top nodes:
LBCs -> LBC -> Nodal BC-> Initial Velocity
Enter value for VY: -5646
Click on Define App Region
Pick all the nodes on the top edge
Click Create
13. Create an auto single surface contact:
LBCs -> Contact-> Automatic -> Auto Single Surface
Click OK on the Auto Single Surface form
14. Select the dyna control options:
Parameters -> Control -> [A to C] -> CONTROL ADAPTIVE
Enter value for ADPFREQ: 1.E-4
Enter value for ADPTOL: 5
Select value for ADPOPT: 2
Enter value for MAXLVL: 2
Enter value for ADPSIZE: 0
Click OK
Control -> [N to Z] -> CONTROL TERMINATION
Enter value for ENDTIME: 3.E-3
Click OK
Control -> [D to H] -> CONTROL ENERGY
Select value for HGEN: 2
Select value for RWEN: 2
Select value for SLNTEN: 2
Select value for RYLEN: 1
331Example - Crushing of a Thin Square TubeCrushing of a Thin Square Tube
Click OK
Control -> [N to Z] -> CONTROL OUTPUT
Select value for NPOPT: 1
Select value for NEECHO: 3
Click OK
Control -> Title ->TITLE
Enter value for Title: Crushing of a thin square tube
Click OK
15. Select the dyna database options:
Database -> OPC -> DATABASE BINARY option
Enter valuEnter value for DT_D3PLOT: 1.E-4
Check in the IOPT select box, and set its value to 1
Click OK
Database -> OPC -> DATABASE option
Enter value for DT_GLSTAT: 2.E-5
Enter value for DT_MATSUM: 2.E-5
Click OK
16. Save the SimXpert database:
File -> Save As
Enter name for the file: square_tube_crush
Click Save
17. Run the Simulation:
Rght-click on Simulations
Enter name for Fle name: square_tube_crush
Click Save
18. Exit from SimXpert:
File -> Exit
19. Post-process the Results in ls-prepost
Crushing of a Thin Square Tube332
Figure 3 Von Mises Stress at Time = 0.003