midas fea 2016 - cspfea - software per l'analisi … information technology co., ltd. fea 2016...

MIDAS Information Technology Co., Ltd. FEA 2016 (v1.1)

Release Note

Post-Processing

1. Supporting 64-bit / GPU-accelerated solver

2. Crack width calculation in the nonlinear analysis of reinforced concrete elements

3. Create reinforcement based on normal stresses of the concrete

2-1. Generating graphs from nonlinear static analysis results

2-2. Update geometry of analysis model using buckling mode shap

01 Improvement about the von-Mises Stresses at Nodes

02 Summation of Crack Widths of Group of Elements

Pre-Processing

1-1. Improvement in data import from midas Civil and midas Gen

1-2. Improvement in ‘Frame to Solid’ and ‘Frame to Plate’ functions

1-3. Creating tendon profiles by entering 3D coordinates

1-4. Improvement in mesh quality of Hexa-Dominant Mesh

01 Fast Fourier Transform in Time-history Graph

02 New Material DB to Korean Standard 03 New Method of Defining Yield Stress–Strain Relations 04 Compression-only Point Spring for Soil Resistance 05 Time Dependent Material to Eurocode 06 DTIME Parameter for User Supplied Material Subroutine

Table of Contents

July 2015


1. Pre Processing

1-1. Improvement in data import from midas Civil and midas Gen

Data import using mct and mgt file

Cross-sections data that are not supported in midas FEA are imported as user-type. Cable elements are imported as truss elements.

Previous version: Nodes and elements are only supported for the import from midas Civil or midas Gen.

FEA 2013 (v1.1): Properties, boundary conditions, loads and analysis data are additionally supported.

File > Import > midas MxT

Civil

FEA

Civil

FEA


1-2. Improvement in ‘Frame to Solid’ and ‘Frame to Plate’ functions

This function converts frame in midas Civil to solid / plate elements in midas FEA.

Previous version: Only one continuous straight line can be converted at a time.

FEA 2013 (v1.1): More than one straight line can be converted at the same time.

Geometry > Frame -> Solid, Frame -> Plate

Frame model

in Civil

Plate model

In FEA

Frame model

in Civil

Plate model

In FEA

1. Pre Processing


1-3. Creating tendon profiles by entering 3D coordinates

This new input method creates tendon profiles of spline or round type in the 3D space by entering 3D coordinates.

The curve types (Spline, Round) which are frequently used in the tendon modeling provides the user with the easier way

to create tendon profiles than previous version.

Geometry > Curve > Create 3D > Tendon Profile

Spline or Round type

Tendon coordinates

Symmetric copy and

rotation of tendon

for convenient tendon

modeling

1. Pre Processing


1-4. Improvement in mesh quality of Hexa-Dominant Mesh

The algorithm of generating hexa-dominant mesh is improved to create mesh with high quality.

Compared to the mesh consisting of tetrahedron only, hexa-dominant mesh in midas FEA provides

more efficient and better analysis results using much smaller number of elements.

1. Pre Processing

Mesh > Auto Mesh > Solid(HEXD)

Tet mesh using

Auto-Mesh Solid

Hybrid mesh using

Auto-Mesh Solid (HEXD)

7568 nodes

19421 element s 3908 nodes : 52% compared to tet mesh

4907 element s: 25% compared to tet mesh

Hex.

Pyramid

Tet.

Trigonal Prism

Generation of hybrid mesh

Hexahedron

Pyramid

Tetrahedron

Pyramid is inserted to connect tetrahedron and hexahedron.

Hexahedrons are created around

the boundary at which high

stresses are expected.

Tetrahedrons are locally created

inside the structure.


2-1. Generating graphs from nonlinear static analysis results

Generate graphs about the relationship of load & displacement and stress & strain for the nonlinear static analysis.

It is possible to draw graphs using the results from different analysis cases.

This feature enables the user to generate graphs easily without the use of MS Excel.

Select node or element

with a relevant component.

Post > Nonlinear Static Analysis > Nonlinear Static Result Graphs

Select a graph type.

2. Post Processing


2. Post Processing

2-2. Update geometry of analysis model using buckling mode shape

Create a new model file in which the geometry of analysis model is revised based on the mode shape of linear buckling analysis. The new model can be used

for geometric and material nonlinear analysis to find a buckling load considering geometric imperfection.

Geometric imperfection can easily be included in the analysis model. The buckling behavior of the model can be further

investigated by performing geometric and material nonlinear analysis.

Post > Linear Buckling Analysis > Update Model with Imperfections Select a buckling mode to revise the

geometry of model.

Buckling mode shape

New analysis model in which nodal

coordinates are updated based on the

selected buckling mode shape and

scale factor.


1. Supporting 64-bit / GPU-accelerated solver

FEA 64-bit solver is capable of accessing memory above the 4GB limit of the Windows 32-bit platform. In a 32-bit operating system there is a limitation of

4GB of memory that can be addressed. Windows reserves 2GB for the operating system leaving only 2GB for external programs. Now huge models can

be analyzed and solution time is much faster.

GPU-accelerated computing offers faster solution times by offloading compute-intensive portions of the solver to the GPU, while the remainder of the

codes still runs on the CPU.

Case studies

Elements 394,986

Nodes 71,816

25 Construction Stages

Elements 504,196

Nodes 79,574

Time History Analysis

5.5 times

System Solution Time

FEA 32-bit 85 min

FEA 64-bit 25min

System Solution Time

FEA 32-bit 316 sec

FEA 64-bit 58 sec

3.4 times


2. Crack width calculation in the nonlinear analysis of reinforced concrete elements

Crack width calculation is one of the serviceability requirements in the structural concrete elements. In design codes, the crack width is estimated based

on the forces and bending moments in the cross section of the structure, which is unreliable for structures with more complex loading and support

conditions.

In Total Strain Crack model, the crack width can be determined as the product of the crack-bandwidth (h) and the difference of maximum principal strain

and maximum principal stress divided by the original Young’s modulus.


3. Create reinforcement based on normal stresses of the concrete

The user can easily generate 3D line objects to be used for reinforcements while checking normal tensile stresses of the concrete.

This feature is useful to create reinforcements in the region with complex geometry and stress variation.

Post > Create Reinforcement

3D line objects • This dialog shows the total tension force of the selected plane and suggests the

required number of reinforcements based on the specified allowable stress and

diameter of reinforcements.

• The tension force of the selected plane is obtained by the Local Direction Force Sum

from the activated elements.

• The final arrangement of reinforcements is defined by the user before generating 3D

line objects.

FEA 2016 (v1.1) MIDAS Information Technology Co., Ltd.

Advanced Nonlinear and

Detail Analysis System

• Using the Fast Fourier Transform algorithm, time history graphs can be converted to frequency history graphs and vice versa.

(1) Fast Fourier Transform in Time-history Graph

Upgrade Contents

Effects & Usage

• Menu: Post > Time History Analysis > Time History Graph (Time ↔ Frequency)

New Feature

• Vibrations of footbridges or building floors due to walking loads can be checked in the frequency domain using FFT so that

resonance frequency can be found.




• Meun: Analysis>Material Manager>Create/Modify Material>Material DB

• KSCE-LSD12(RC), KS09(S), KS08(S), KSCE-LSD12(S), KS10-Civil(S), KS08-Civil(S)

(2) New Material DB to Korean Standard

Upgrade Contents

New Feature




• Menu: Analysis>Material

• In the case of plastic materials, the constitutive model defines an elastic limit as a function of the equivalent plastic

strain, which can be calculated based on the plastic strain obtained from the uni-axial tension test as follows. In the

new version, the strain hardening can be defined based on the uni-axial plastic strain. The program will automatically

convert it into the equivalent plastic strain.

(3) New Method of Defining Yield Stress–Strain Relations

Upgrade Contents

New Feature

p

1 p

13

2

3

2

p

13

2

3

2 - von Mises - Tresca - Rankine

Equivalent plastic strain Uniaxial plastic strain




Right-Clicking

• The existing input method based on Equivalent Plastic Strain can be accessed

from the Tree Menu.

• Menu: Tree menu>Function>Add Strain Hardening Function




• Menu: Mesh>Element>Create Surface Spring>Point Spring

• Point Spring with Compression-Only type can simulate the elastic behavior of soil resistance.

(4) Compression-only Point Spring for Soil Resistance

Upgrade Contents

New Feature




• Menu: Analysis>Time Dependent Material>Creep/Shrinkage, Compressive Strength

• Prestressed structures can be analyzed with the effects of creep, shrinkage and compressive strength to Eurocode.

(5) Time Dependent Material to Eurocode

Upgrade Contents

New Feature




• SUBROUTINE USRMAT (EPSO, DEPS, EPSP, NS, INFM_STEP, COORD, SE, USRVAL, NUV, USRSTA, NUS,

IUSRIND, NUI, SIG, STIFFM, ID, DETJ, DTIME), DTIME: Total Time Increment

(6) DTIME Parameter for User Supplied Material Subroutine

SUBROUTINE USRMAT (EPSO, DEPS, EPSP, NS, INFM_STEP, COORD, SE, USRVAL, NUV,

USRSTA, NUS, IUSRIND, NUI, SIG, STIFFM, ID, DETJ, DTIME)

New Feature

FEA 2016 (v1.1)

Upgrade Contents

• The user can program the material which is dependent on time, e.g. visco-elastic model.

MIDAS Information Technology Co., Ltd.



FEA 2016 (v1.1)

• von-Mises stresses including Tresca and Rankine cannot exceed yield stress at nodal points as well as integration points.

(1) Improvement about the von-Mises Stresses at Nodes

Upgrade Contents

Post Process




FEA 2016 (v1.1)

• In the total strain crack model, the crack with of single element depends on the element size. Summation of crack

widths of group of elements is provided so that the crack with within certain distance can be checked regardless of

mesh size.

(2) Summation of Crack Widths of Group of Elements

Upgrade Contents

Post Process

Select elements




FEA 2016 (v1.1)

(1) Convergence Error with Combined Cracking-Shearing-Crushing model

Problem

Convergence error in nonlinear analysis of interface elements with the

‘Combined Cracking-Shearing-Crushing’ material model. ● Analysis> Material > Interface

Related Functions

Correction

Improvement of convergence algorithm of CCSC material model.

19

(2) Incorrect Self Weight of Pyramid Element

Problem

Incorrect total weight with the model consisting of pyramid elements.

Correction

Corrected.

● *.OUT Files

Related Functions




FEA 2016 (v1.1)

(3) Convergence Error in Nonlinear Analysis with Plate Offset

Problem

Convergence error in nonlinear analysis with plate offset.

● Analysis > Property > Plate

Related Functions

Correction

Improved.

midas fea 2016 - cspfea - software per l'analisi … information technology co., ltd. fea 2016...

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