ABAQUS Workshop Slides 0

What you will learn from this workshop?

� How to launch ABAQUS from EOS (supercomputing facility)

� How to use the ABAQUS manual

� How to download an example file from ABAQUS manual and how to import it

into ABAQUS?

� Preprocessing, running the analysis and post processing using the following

examples

a) Example 1: 3D stress analysis

b) Example 2: Transient Heat transfer Analysis

c) Example 3: Extrusion of metal (Dynamic Explicit Analysis)

d) Example 4: Frequency Analysis of Gear

e) Example 5: Modeling of 2D particle reinforced composite

f) Example 6: Modeling of 3D particle reinforced composite

2PREPARED BY PRADEEP GUDLUR, TEXAS A & M UNIVERSITY Objectives

3PREPARED BY PRADEEP GUDLUR, TEXAS A & M UNIVERSITY

File type Purpose

.caea) All the preprocessing can be done with this

b) Can be opened with ABAQUS CAE

.inp

a) Analysis input file.

b) One of the ways to generate an input file is by using ABAQUS CAE

c) Contains all the information related to the problem (ex: coordinates of nodes, element connectivity matrix, element type, material

props, step, type of analysis performed, boundary conditions, loads etc).

d) input file can be opened with wordpad and can be edited. It can also be imported into ABAQUS CAE.

e) Using the following command input file is run: abaqus job=jobname.inp

.odb a) Results file written by the analysis.

b) Can be opened with ABAQUS viewer (opens in the visualization module) and any postprocessing can be performed.

.sta

a) Status file. The analysis writes incremental summaries to this file

b) We can know step time, total time, CPU time, increment number, # of equilibrium iterations, severe discontinuity iterations etc in a

tabular format

c) Can be opened with wordpad

d) You should see “ The analysis has completed successfully” in the status file. otherwise analysis didn’t complete and the errors can be

seen in .msg and .dat files if they exist

.msg

a)Message file written by the analysis

b)contains any error or warning messages, convergence checks, step time, total time, incrementation and other important information

written for each iteration and increment of each step

c) can be opened with wordpad

.dat

a)Print output file written by the analysis (you can use *Node Print, *El Print in the .inp file to write nodal and elemental ouputs in a

tabular format in the .dat file)

b)contains any error or warning messages with other important information written for each iteration and increment of each step

c) can be opened with wordpad

.fil

a) Results file written by the analysis

b) You can use *Node File, *El File in the .inp file to write nodal and elemental ouputs to the .fil file of one analysis, which can be used

in another analysis. Ex: sequentially coupled thermo-mechanical analysis

c) can’t be opened with wordpad or ABAQUS viewer

Introduction

4PREPARED BY PRADEEP GUDLUR, TEXAS A & M UNIVERSITY Introduction

Command Purpose

module load abaqus to invoke abaqus modules in EOS

abaqus cae to launch abaqus

abaqus cae -mesa to launch abaqus (if there is graphics

problem with above command)

abaqus job=jobname.inp to run the input file “jobname.inp”

module load intel-compilers to load fortran compilers in EOS

abaqus job=jobname.inp user=fortranname.f to run an input file “jobname.inp”

along with user subroutine

“fortranname.f”

abaqus fetch job=jobname.inp to copy an input file from abaqus

example problems manual to your

present working directory

man abaqus to get a detailed description of

various commands of abaqus on EOS

abaqus help some more commands

Before going into examples you should know the following things

� Units:

Abaqus has no units built into it (except for rotational DOF (radians) and other angle measures(degrees)). Therefore, the units chosen must be self-consistent >> Refer: 1.2.2 Analysis user’s manual

� DOF: Primary variables

a) Ex: Temperature(for heat transfer analysis); Displacements-translational & rotational(for mechanical analysis); Temperature + displacements (for thermomechanical analysis)

b) Displacements or other degrees of freedom are calculated at the nodes of the element. At any other point in the element, the displacements are obtained by interpolating from the nodal displacements.

� Stress and strain measures:

a) Stress is always reported as >> Cauchy or true stress

b) Shear strain is always reported as >> engineering shear strain

c) True strain is not that useful and therefore ABAQUS has different strain measures (Integrated strain, Green’s Strain, Nominal Strain, Logarithmic strain>> Refer: 1.2.2 Analysis user’s manual)

d) By default Stress and strains are calculated at integration points. If specified ABAQUS can interpolate these values to obtain at nodes or centroid of the element

� Time:

a) Step time>> measured from the beginning of each step

b) Total time>> starts at zero and is the total accumulated time over all the steps(except Linear perturbation)


� Incrementation:

Each step in an Abaqus analysis is divided into multiple increments. And 2 choices for incrementation.

a) Automatic Incrementation>> Just define the step and specify certain tolerances or error measures, Abaqus then automatically selects the increment size as it develops the response in the step.

b) Fixed incrementation:>> Increment size is specified by the user. If you have a good “feel” for the convergence behavior of the problem.

c) Automatic incrementation is recommended for most cases.

� Types of Iterations:

ABAQUS attempts to perform multiple iterations for each increment until convergence is obtained

a) Equilibrium iterations >> the solution varies smoothly;

b) Severe discontinuity iterations (SDIs)>> abrupt changes in stiffness occur.

c) These can be seen in “.sta” file


c) # of nodes in an element is clearly identified in its name.

(S4R>> 4 node shell element ; C3D8>> 8 node brick element)

a) Commonly used element families in a stress analysis.

b) The first letter indicates to which family the element belongs

(S4R>> shell element; C3D8>> continuum element)

7IntroductionPREPARED BY PRADEEP GUDLUR, TEXAS A & M UNIVERSITY

8IntroductionPREPARED BY PRADEEP GUDLUR, TEXAS A & M UNIVERSITY

Example 1: 3D Stress Analysis

PREPARED BY PRADEEP GUDLUR, TEXAS A & M UNIVERSITY 9EXAMPLE 1

10PREPARED BY PRADEEP GUDLUR, TEXAS A & M UNIVERSITY EXAMPLE 1



The section property provides any additional data required to

define the geometry of the element and also identifies the

associated material property definition.




















Example 2: Transient Heat Transfer Analysis


Refer: Section 2.11.1 Abaqus Theory manual







Make sure BC-0temp is inactive (not propagated) in Step-1









Example 3: Extrusion of metal (Dynamic explicit

analysis)





This surface will be later used in “Interaction module”

to define contact between different surfaces

Choose magenta as metal is going to come in contact

with top surface of the bottom die




This surface will be later used in “Interaction module”

to define contact between different surfaces

Choose yellow as metal is going to come in contact

with bottom surface of the top die




These surfaces will be later used in “Interaction

module” to define contact between different surfaces








Refer section

15.14.1 of CAE

user’s manual


Refer section

15.13.6 of CAE

user’s manual








Example 4: Frequency Analysis of Gear


Refer: Section 2.5.1 Abaqus Theory manual



Choose Y-axis


When asked to choose edge or

axis, choose the datum axis

created in last slide




Purpose of creating datum plane will be

explained in next slide


When asked to

select a plane for

extrusion, select

the datum plane

as shown in the

picture (the

datum plane was

created in the

last slide for this

purpose)










Refer: sections 7.5 and 7.6 of “ Getting

started with Abaqus interactive edition”

manual >> for a more detailed post-

processing of a similar problem

Example 5: Modeling of 2D Particle Reinforced

Composite






Example 6: Modeling of 3D Fiber Reinforced

Composite








1) ABAQUS manual: http://sc.tamu.edu:2080/v6.9ef/

2) Matweb, online materials property database: www.matweb.com

Documents

ABAQUS Workshop Slides 0