femap v12 nx nastran multistep nonlinear solutions · 2018-11-18 · • sol 402 multistep...

Femap v12

NX Nastran Multistep Nonlinear Solutions

Unrestricted © Siemens AG 2018

2018-05-08 Siemens PLM Software

Agenda

Overview of NX Nastran Multistep Nonlinear Solutions

SOL 401

SOL 402

Comparison of SOL 401 vs SOL 402

Q&A



Evolution of the NX Nastran Nonlinear Solutions

Samcef

solver

• Material Library

• Element Formulations

• Matrix Solvers

• Memory Allocation

• Output Formats

• Numerical Strategies

SOL 402

(+ environment)

Products

Solvers

Technologies

SOL 401

(+ environment)

Samcef

(+ environment)+ user interaction

Core solver engines and

associated architectures

• Components and algorithms

• Element and result consistency

• Leverage strength of each engine

NX Nastran

solver

NXN Multistep Samcef



NX Nastran Multistep Nonlinear

SOL 401 and 402 Core Capability

• Multi-Step solutions

• Large displacement

• Plasticity

• Creep

• Contact

• Material Models

SOL 402 Difference

• Composites

• Nonlinear mechanism

SOL 401 Difference

• Multiphysics couplings

Planned

Commonalties/Differences

Multistep Solutions:

• SOL 401 and 402 provides general purpose non-linear solution capability

• SOL 401 Multistep – based on traditional NX Nastran architecture

• SOL 402 Multistep Kinematic – based on integration of Samcef in NX Nastran

Applicability

• SOL 401 and SOL 402 similarities

• Use many of the same formulations and give nearly same results

• Core set of capabilities that are the same and can be used for same applications

• Use same Nastran inputs and outputs. Easy to convert one solution to the other

SOL 401 and SOL 402 differentiations

• SOL 402 can better support nonlinear kinematic behavior

• SOL 401 can be used for multiphysics co-simulation

SOL 401



SOL401 Multistep Solution

Support for SOL 401 added in Femap 12.0

Subcases declared Sequentially Dependent or

Not Sequentially Dependent

Contact conditions can change between Subcases

Iteration controls can change between Subcases

Analysis type can change between Subcases

• Analysis Types: Statics, Preload Bolt and Modal

are supported by Femap UI

• Subcase 1

• Analysis = Statics

• Subcase 2

• Analysis= Modal



SOL401 NX Nastran Elements

Line Elements

• Bar

• Beam

• DOF Spring

Plane Elements

• Plate

• Laminate

• Plane Strain

Volume Elements

• Axisymmetric

• Solid

• Solid Laminate

• Solid Cohesive

0D (Other) Elements

• Spring/Damper to Ground

• DOF Spring to Ground

• Rigid



SOL401 NX Nastran Element/Material/Solution Support

Materials Nonlinearity Solutions

Isotropic Orthotropic Anisotropic Creep

Large

Displacement Plasticity Statics Preload Modal

Bar

Beam

Plate

Laminate

Generalized

Plane Strain

Axisymmetric

Solid

Solid Laminate



SOL401 0D, 1D Element Support

Bar and Beam Elements

• Large displacement with offsets supported

DOF Springs

• Nonlinear springs supported

• Large displacement not supported

Rigid

• RBE2, RBE3 supported

• MPCs, RBE1 NOT supported

Spring/Damper to Ground and DOF Spring to Ground

• Nonlinear Springs supported

• Large displacement not supported



SOL401 2D Element Support

NX Nastran 12 added supported for shell elements

• Plate offsets for large displacement are supported

• CQUAD/CTRI3 automatically converted to CQUADR/CTRIAR internally

• For CQUAD8/CTRIA6 elements – K6ROT can be used to add drilling stiffness for use in curved plates

• Nonlinear Plastic and Creep shell elements –

• Allow the specification of the number of points throughout the element thickness (3, 5, 7 or 9) using the

NLAYERS parameter

• For Plastic and Creep materials, MID1, MID2, MID3 must be identical, MID4 not allowed

• Plane Strain elements CPLSTN3, CPLSTN4, CPLSTN6, CPLSTN

• Plane Stress elements CPLSTS3,CPLSTS4, CPLSTS6, CPLSTS8



SOL401 Solid Element Support

Solid Elements

• CTETRA, CHEXA, CPENTA and CPYRA

• Axisymmetric elements CQUADX4, CQUADX8, CTRAX3, CTRAX6



SOL 401 Cohesive Elements

Cohesive elements are used to model adhesively bonded interfaces

• Compliance in the Connection

• Damage in the material

• Two new element types: CHEXCZ and CPENTACZ

• Can occupy a solid volume or collapse to planar area

• NXN uses thickness from Property entry;

• NOT the thickness based on grid locations for the stiffness calculations

• Must reference PSOLCZ Property entry

• Material can be one of the following:

• MAT1: K01 = K02 = G / THICK, and K03S = E / THICK, where THICK is the value on the PSOLCZ bulk entry.

• MAT11: K01 = G13 / THICK, K02 = G23 / THICK, and K03S = E3 / THICK, where THICK is the value on the

PSOLCZ bulk entry

• MATCZ: Enter K01,K02,K03S on the MATCZ

• THICKness value defined for the Property is ignored



Cohesive Elements

Cohesive elements can be created in Femap via the new meshing command

Mesh > Editing > Cohesive Meshing

• Inserts layer of solid cohesive elements



Cohesive Material

MATCZ is used to obtain material damage estimates

• Damage estimates require material Plasticity Option

• PARAM,MATNL,1



New concept of Connector Sets (Glue or Contact)

Similar to Nastran Reference Constraint and Load Sets

Can be used to designate Connectors used in a Master Case or Subcase

SOL 401 Contact Modeling

RMB




Glue Only specified in Master Case

Contact Connections can be changed between Subcases

Master Case Boundary Conditions Sub Case Boundary Conditions



SOL 401 Contact Connection Property

Use “Default” button to autofill most settings

New NOSEP option prevents surfaces in contact from flying

apart when the regions in contact are unloaded



SOL 401 Glue Connection Property

Use “Default” button to autofill most settings

Sliding Glue option allows sliding but no separation



SOL401 FEMAP support – multi-step control

Setup in the FEMAP Analysis Set Manager

Time Step and Solution Control in each Subcase

Example -

• Case 1 – ramps the structure up through a

nonlinear static case

• Case 2 – uses the stiffened results of case 1

and runs a modal solution

BC in Global

Static Case

Ramps up Force

Modal Case Seq. Dep.



SOL401 Preview Input

Setup in the Femap Analysis Set Manager

Time step and solution control in each

subcase

Example

• Case 1 – ramps the structure up through a

nonlinear static case

• Case 2 – Uses the stiffened results of case

1 and runs a modal solution

BC in Global

Static Case

Ramps up Force

Modal Case Seq. Dep.



SOL 401 Master and Subcase Analysis Types

Statics

Normal Modes/Eigenvalue

Bolt Preload

• Only available in a SUBCASE

Buckling

• Not supported by the Femap GUI - edit SUBCASE(s) to add a

NLARCL=AnalysisType



SOL 401 Multistep Control Options

Control Options Can Be Changed Between Cases



SOL 401 Multistep Nonlinear Time Steps

Mechanical and thermal loads can optionally be defined as a function of time in a static subcase

These time-assigned loads only use time as the mechanism to increment the loads.

Time Steps Are Set for Each Subcase

User Specifies the End Time,

Number of Increments and

Output Frequency

Start Time Is A Function of Case Being Sequentially Dependent or NSD

• Not Sequentially Dependent; Start Time is 0.0

• Sequentially Dependent; Start Time is End of Previous Case

Non time assigned loads can be ramped or stepped



NX Nastran Multi-Step Nonlinear

Starting Model Case 1 – Deformed and Stiffened

Case 2 – Stiffened Model Mode 1

SOL 402



SOL402 Nonlinear Multistep Kinematics

SOL 402 is a multi-step, structural solution that supports a combination of subcase types (static linear, static

nonlinear, nonlinear dynamic, preload, modal, Fourier, buckling) and large rotation kinematics.

SOL 402 allows a combination of the following subcases. The ANALYSIS case control command defines the

subcase analysis type with the Femap GUI

• STATICS (Nonlinear) static analysis.

• MODES Normal Modes.

• PRELOAD Bolt Preload subcase computation.

Additional Subcase types supported in NX Nastran 12 – requires manual editing of the Subcase ANALYSIS card

• DYNAMICS (Nonlinear) dynamic analysis, including damping and inertia effects.

• CYCMODES Cyclic Normal Modes.

• FOURIER Fourier Normal Modes.

• BUCKLING Buckling Modes (Incremental Stability)



SOL402 NX Nastran Elements

Line Elements

• Bar

• Beam

• Rod

• DOF Spring

• Gap

Plane Elements

• Plate

• Laminate

• Plane Strain

Volume Elements

• Axisymmetric

• Solid

• Solid Laminate

• Solid Cohesive

0D (Other) Elements

• Mass

• Mass Matrix

• Spring/Damper to Ground

• DOF Spring to Ground

• Rigid



SOL402 NX Nastran Element/Material/Solution Support

Materials Nonlinearity Solutions

Isotropic Orthotropic Anisotropic Creep

Large

Displacement Plasticity Statics Preload Modal

Rod

Bar

Beam

Plate

Laminate

Generalized

Plane Strain &

Plane Stress

Axisymmetric

Solid

Solid Laminate



SOL402 1D and 0D Elements

1D Elements

• BEAM, BAR

• ROD

• GAP

0D Elements

• Springs – Linear and Nonlinear

• Dampers – Linear and Nonlinear

• RBE2, RBE3

• MASS

MPCs are also supported



SOL402 2D (Surface) Elements

Plate Elements:

• CQUAD4,CTRIA3,CQUADR,CTRIAR,CQUAD8,CTRIA6

• CQUAD4 and CTRIA3 must be converted to CQUADR and CTRIAR in the Femap Bulk Data Form

• 2D Plane Strain

• 2D Plane Stress



SOL402 Solid Elements

Solid Elements:

• CHEXA, CPYRAM, CTETRA, CPENTA

• 3D Axisymmetric elements: CTRAX3, CTRAX6, CTRIAX, CQUADX4,

CQUADX8, CQUADX

• Solid Cohesive elements: CHEXCZ, CPENTCZ



SOL 402 Hyperelastic Materials

Three (3) Hyperelastic material types available

• Mooney-Rivlin

• Hyperfoam

• Ogden




Solid and Beam Bolted Connections

Rigid Connection Regions

Glued or Contact Connector Sets, similar to Nastran Reference Constraint and Load Sets can be used to

designate Connectors used in a Master or Subcase



SOL 402 Contact and Glued Connection Properties



SOL 402 Analysis Set



SOL 402 Analysis Type and Control Options



SOL 402 Multistep Nonlinear Time Steps

Mechanical and thermal loads can optionally be defined as a function of time in a static subcase.

These time-assigned loads only use time as the mechanism to increment the loads.

• Time Steps Are Set for Each Subcase

• User Specifies the End Time, Number of Increments, Output Frequency

• Start Time Is A Function of Case Being Sequentially Dependent or NSD

• Not Sequentially Dependent; Start Time is 0.0

• Sequentially Dependent; Start Time is End of Previous Case

• Non Time Assigned Loads Can be Ramped or Stepped

SOL 401 vs 402

Comparison



SOL 402 vs SOL 401 Comparison

General

• SOL 401 can be used for multiphysics co-simulation

• SOL 402 should be used to simulate nonlinear kinematic behavior

Contact

• In SOL 401, the OFFSET distance can be defined per contact region (BCRPARA bulk entry)

• In SOL 402, the OFFSET distance is defined at the contact level (BCTPAR2 entry).

• In SOL 401, a contact with shells automatically take the half thicknesses of the shells into account.

• In SOL 402, must manually take the half thicknesses of the shells into account with the OFFSET parameter

for the Connection Property used for that Connection



SOL 402 vs SOL 401 Bolt Comparison

SOL 401

• Bolts can only modeled with solid elements

• You also cannot use CPYRAM and/or composite solids for a BOLT of the ETYPE=3 type.

• Bolt loading sequence (BOLTSEQ) is allowed in SOL 401

• Initial strain bolt preload force is allowed in SOL 40I

SOL 402

• Bolts can be modeled using beams and solid elements

• Bolts are activated for the whole subcase time interval.



SOL 402 vs SOL 401 SUBCASE Comparison

In SOL 401, a NSD subcase (SEQDEP = NO) has a start time of zero. In addition, a non-sequentially

dependent static or modal subcase does not use the displacement/stress/strain state from the previous

static subcase.

In SOL 402, a NSD subcase uses the final time from the previous subcase for its start time. But the

computation state (stresses, state variables, and so on) can be reloaded from the end of any of the

previous subcases through the RSUB parameter of the NLCNTL2 bulk entry.



Multistep Nonlinear Documents

SOL 401 - Multi-Step Nonlinear User’s Guide: multi_step_nonlinear.pdf

SOL 402 – NX Nastran 12 Release Guide, Chapter 6: release_guide.pdf



Q&A

Backup



SOL 402 Multi-Step Global Strategy Control Options