Overview of Abaqus

Lecture 1

Overview

• • • • • • • • • • • •

SIMULIA What is Abaqus FEA?

Overview of Abaqus/CAE Starting Abaqus/CAE Overview of Abaqus/Standard and Abaqus/Explicit Abaqus Conventions Documentation Abaqus Environment Settings Abaqus Fetch Utility Abaqus/CAE Checklist Working with the Model Tree Workshop 1: Linear Static Analysis of a Cantilever Beam Introduction to Abaqus

L1.2

SIMULIA

L1.4

SIMULIA

•

SIMULIA is the Dassault Systèmes brand that delivers a scalable portfolio of Realistic Simulation solutions including

• The Abaqus product suite for Unified FEA • Multiphysics solutions for insight into challenging engineering problems • Lifecycle management solutions for managing simulation data, processes, and intellectual property •

Headquartered in Providence, RI, USA

• R&D centers in Providence and in Velizy, France •

Global network of regional offices and distributors Introduction to Abaqus

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SIMULIA

SIMULIA Headquarters: Providence, Rhode Island Offices: USA:

California Ohio Indiana Rhode Island

Overseas:

Australia Finland India Korea UK (2) Austria France Italy Netherlands

Representatives: Overseas:

Argentina Malaysia Russia Spain Brazil New Zealand Singapore Taiwan Michigan Texas China Germany (2) Japan (2) Sweden Czech Republic Poland South Africa Turkey

Introduction to Abaqus

What is Abaqus FEA?

What is Abaqus FEA?

•

Suite of finite element analysis modules

L1.7

Introduction to Abaqus

L1.8

What is Abaqus FEA?

•

The structural analysis “solver” modules, Abaqus/Standard and Abaqus/Explicit, are complementary and integrated analysis tools.*

• Abaqus/Standard is a general-purpose finite element module. It provides a large number of capabilities for analyzing many different types of problems, including many nonstructural applications.

• Abaqus/Explicit is an explicit dynamics finite element module.

• Abaqus/CAE incorporates the analysis modules into a

C

omplete

Abaqus E

nvironment for modeling, managing, and monitoring Abaqus analyses and visualizing results.

* Abaqus/CFD is a computational fluid dynamics analysis product; it is not discussed in this course.

Introduction to Abaqus

Overview of Abaqus/CAE

Overview of Abaqus/CAE

• Integrates modeling, analysis, job management, and results evaluation seamlessly.

• Provides the most complete interface with the Abaqus solver programs available.

• Uses neutral database files that are machine independent.

• Can be customized to create application specific systems.

Abaqus/CAE main user interface

Introduction to Abaqus

L1.10

Overview of Abaqus/CAE

•

Modern graphical user interface (GUI) of menus, icons, and dialog boxes

• Menus provide access to all capabilities.

• Icons accelerate access to frequently used features.

• Dialog boxes allow you to input alphanumeric information and to select various options.

Mechanical property submenu Visualization toolbox icons

Introduction to Abaqus

Elastic material form

L1.11

Overview of Abaqus/CAE

•

Consistent environment

• Functionality is presented in modules.

• Each module contains a logical subset of the overall functionality.

• Once you understand the presentation of one module, you can easily understand the presentation of the other modules.

Introduction to Abaqus

L1.12

Overview of Abaqus/CAE

• Create the part geometry (and regions for sections, if necessary)

Part Step

• Define analysis steps and output requests • Split assembly into meshable regions and mesh

Mesh Property Assembly

• Define materials • Define additional • Position parts for initial configuration.

part regions • Define and assign sections to parts or regions

Interaction Load

• Define contact and other interactions on regions or named sets, and assign them to steps in the analysis history • Apply loads, BCs, and ICs to regions or named sets; and assign them to steps in the analysis history

Job Visualization

• Submit, manage, and monitor analysis jobs • Examine results

Introduction to Abaqus

L1.13

Overview of Abaqus/CAE

•

Model Tree and the Results Tree

• The Model Tree provides you with a graphical overview of your model and the objects that it contains.

• The Results Tree is used to display analysis results from output databases as well as session specific data such as

X –Y

plots. • Both trees provide shortcuts to much of the functionality of the main menu bar, the module toolboxes, and the various managers.

• Some features of the Model and Results trees are discussed next.

Introduction to Abaqus

L1.14

Overview of Abaqus/CAE

•

Tree features

•

Navigation tool

• Context sensitive RMB actions  edit/create/suppress/query • Can effectively build most of your model from the tree •

Model query/auditing

• E.g., shows number of sections, materials, constraints currently defined • Shows status of certain features/items (invalid part, suppressed feature) •

Comprehensive view of Abaqus model data

• “Containers” expand to show objects and their hierarchy • Step dependent objects (e.g., BCs) appear in the STEP and LOAD containers

Introduction to Abaqus

L1.15

Overview of Abaqus/CAE

• • • •

Tool tips

• Float the mouse over a container or item…

“Pruning” the tree

• You can set a certain container as the new “root” to reduce clutter

Keyboard shortcuts

• Hide/show • Expand/collapse • Search • Delete items • Switch context

Filtering Introduction to Abaqus

L1.16

Overview of Abaqus/CAE

•

Models are feature-based and parametric

• • A feature is a meaningful piece of the design. Models are constructed from numerous features; for example:

Geometric features

• Solid extrusion, wire, cut, fillet, etc.

fillet •

Assembly features

• Wheel must be concentric with the axle, the blank lies exactly in contact with the rigid die, etc.

•

Mesh features

• Partition the mesh into different regions for different meshing techniques, seed different edges with different mesh densities, etc.

Introduction to Abaqus

solid extrusion cut Part with several annotated features

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L1.18

Overview of Abaqus/CAE

• • • • A parameter is a modifiable quantity that provides additional information for a feature; for example:

Solid extrusion parameters

• Sketch of extrusion cross section, depth of extrusion.

Cut

• Sketch of cut cross-section, depth of cut.

Fillet parameter

• Fillet radius.

sketch of extrusion cross-section extrusion depth

Introduction to Abaqus

Solid extrusion parameters

Overview of Abaqus/CAE

• Features often have parent-child relationships, such that the existence of the child depends on the existence of the parent; for example: • Delete the solid extrusion, and the hole and fillet cannot exist.

• Delete the part, and the mesh cannot exist.

• Abaqus/CAE always asks to make sure that you want to delete the parent and its child features.

fillet solid extrusion cut • parent:

solid extrusion

• child:

cut

• child:

fillet

Example of Parent-Child Relationships among Features

L1.19

Introduction to Abaqus

Overview of Abaqus/CAE

• Features can be modified by editing their parameters. • Aspects of the model can be regenerated.

• Parametric studies are easy and natural.

• Features can also be deleted or temporarily suppressed with the option to resume them later.

• If a parent feature is deleted or suppressed, all its child features are also deleted or suppressed.

Introduction to Abaqus

L1.20

L1.21

Overview of Abaqus/CAE

•

Interoperability

• Abaqus/CAE is based on the concepts of parts and assemblies, which are common to many CAD systems.

• Parts can be created within Abaqus/CAE.

• Geometry can be imported from other packages and exported to other packages.

• Existing Abaqus meshes can be imported for further processing.

• Individual models can be copied between databases.

Introduction to Abaqus

L1.22

Overview of Abaqus/CAE

•

Dockable toolbars

• Allow you to modify the layout and appearance of toolbars • Individual toolbars can be moved by dragging the toolbar grip • Toolbars can be “docked” at any of four docking regions located around the main window • Floating toolbars can be located anywhere • Orientation of floating toolbars can be controlled Dock Sites

Introduction to Abaqus

Overview of Abaqus/CAE

•

Custom toolbars

• Include shortcuts to functions not in standard toolbars or toolboxes • Can collect commonly used functions • To add a function to a custom toolbar: •

Tools → Customize

• Select the function in the

Customize

dialog box • Drag it onto the custom toolbar.

• Assign an icon to represent the toolbar • Can be moved, docked, floated, or hidden in the same way as standard toolbars

Introduction to Abaqus

L1.23

Overview of Abaqus/CAE

•

Custom keyboard shortcuts

• Available for most functions. • E.g., the key combination

[Shift] + [Ctrl] + P

to

Create Part

may be assigned dialog box • Default keyboard shortcuts for common functions (save, print, etc.) can also be reassigned.

• Keyboard shortcuts must use one of the following keys or key combinations: • • Any function key except

F1 [Alt] + [Shift] + key

•

[Ctrl] + key [Alt]

. You can also add or

[Shift]

to modify any keyboard shortcut that includes the

[Ctrl]

key.

Introduction to Abaqus

L1.24

Overview of Abaqus/CAE

•

View manipulation

• Toolbar to control view (pan, zoom, rotate, etc.).

• Alternatively, can use a combination of keyboard and mouse actions: • Rotate: [Ctrl]+[Alt]+MB1.

• Pan: [Ctrl]+[Alt]+MB2.

• Zoom: [Ctrl]+[Alt]+MB3.

• You can reconfigure these combinations to mimic the view manipulation interfaces used by other common CAD applications

Introduction to Abaqus

L1.25

Overview of Abaqus/CAE

•

3D compass

• View manipulation tool • Provides a quick and convenient way to change model view • Appears by default in each viewport; can be turned off if necessary • Uses three axes to indicate current model orientation • Can be clicked, dragged and oriented; by clicking different areas, specialized view manipulations can be performed: • Rotate freely about the model's center of rotation.

• Rotate about a fixed axis.

• Pan camera along a fixed axis.

• Pan camera within a fixed plane.

• Apply a predefined view.

Introduction to Abaqus

L1.26

Overview of Abaqus/CAE

•

What is a model database file (extension .cae

)?

• Contains all the information for any number of models.

• Typically contains one model or several related models.

• Only one model database can be opened in Abaqus/CAE at a time.

L1.27

Model 1

Model database ( .cae

)

Model 2 Model 3

Introduction to Abaqus

L1.28

Overview of Abaqus/CAE

•

What is a model?

• Contains all the necessary information for an analysis.

• Contains any number of parts and their associated properties.

• Is independent of other models in the model database.

• Objects such as parts and materials can be copied between different models in the same database.

• Contains a single assembly of part instances, including the associated contact interactions, loads and boundary conditions, mesh, and analysis history.

Model 1 parts material properties 1 assembly 1 analysis history

Introduction to Abaqus

Overview of Abaqus/CAE

•

Models can be imported into one database from another

• Model data from the imported database is copied into the current database.

• E.g., parts, sections, assemblies, materials, loads, BCs, etc.

• Analysis job definitions and custom data are not copied User A

+

User B

= Introduction to Abaqus

Master Model

L1.29

Overview of Abaqus/CAE

•

What is Python?

• Command language used by Abaqus/CAE.

• Uses range from command scripting to creating customized applications.

• Powerful and easy-to-use public domain, object-oriented programming language.

• There are several books available on Python programming.

• Additional learning materials are available online at

www.python.org

.

• It is not necessary to learn Python programming to use Abaqus/CAE.

Introduction to Abaqus

L1.30

L1.31

Overview of Abaqus/CAE

•

Commands issued during an Abaqus/CAE session are saved in journaling files containing Python scripts.

Replay ( Journal ( .rpy

Recover ( .jnl

) file .rec

) file ) file

All commands executed during a session, including any mistakes, are saved in this file.

All commands necessary to recreate the most currently saved model database (

.cae

) are saved in this file.

All commands necessary to recreate the model database (

.cae

) since it was most recently saved are saved in this file.

• Journaling files can be modified in any way appropriate for the Python language.

Introduction to Abaqus

Starting Abaqus/CAE

Starting Abaqus/CAE

•

Three options available:

• Command line •

abaqus cae = filename.cae

• Opens Abaqus/CAE in current directory • Start menu (Windows) • Opens Abaqus/CAE in startup directory (set during installation) • Working directory can be changed (see next slide) • Double-click

.cae

or

.odb

file in Windows folder • Opens Abaqus/CAE in current directory

Introduction to Abaqus

L1.33

Starting Abaqus/CAE

•

Selecting a working directory

• Can select a working directory • Default is startup directory • Subsequent file operations will use this directory for reading/writing • Job files will be written to the new working directory • This makes it easier to manage job files • E.g., keep all job files in a per-job directory

L1.34

Introduction to Abaqus

Overview of Abaqus/Standard and Abaqus/Explicit

Overview of Abaqus/Standard and Abaqus/Explicit

•

Abaqus/Standard

• General-purpose finite element code.

• Extensive and independent libraries: • Elements • Materials • Analysis procedures • Robust contact capability

L1.36

Introduction to Abaqus

Overview of Abaqus/Standard and Abaqus/Explicit

•

Abaqus/Standard analysis types

• Static stress/displacement analysis: • Rate-dependent or rate independent response • Eigenvalue buckling load prediction

L1.37

Articulation of an automotive boot seal

Introduction to Abaqus

L1.38

Overview of Abaqus/Standard and Abaqus/Explicit

• Linear dynamics: • Natural frequency extraction • Modal superposition • Harmonic loading • Response spectrum analysis • Random loading • Linear/Nonlinear dynamics: • Transient dynamics • Implicit or explicit integration Harmonic excitation of a tire

Introduction to Abaqus

Overview of Abaqus/Standard and Abaqus/Explicit

•

Other analysis types available in Abaqus/Standard:

• Heat transfer • Acoustics • Mass diffusion • Steady-state transport

L1.39

Steady-state rolling of a tire on a drum traction free rolling braking

Introduction to Abaqus

L1.40

Overview of Abaqus/Standard and Abaqus/Explicit

•

Multiphysics with Abaqus/Standard:

• Thermal-mechanical analysis • Structural-acoustic analysis • Thermal-electrical (Joule heating) analysis • Linear piezoelectric analysis • Fully or partially saturated pore fluid flow-deformation • Fluid-structure interaction Thermal stresses in an exhaust manifold

Introduction to Abaqus

L1.41

Overview of Abaqus/Standard and Abaqus/Explicit

•

Abaqus/Explicit

• General-purpose finite element code for explicit dynamics • Designed for optimal computational performance with large models running many (10,000 to 100,000+) time increments • Extensive element and material libraries • Robust contact capability

Introduction to Abaqus

Overview of Abaqus/Standard and Abaqus/Explicit

•

Abaqus/Explicit (cont’d)

• Simulates high speed dynamic events such as drop tests.

• Explicit algorithm for updating the mechanical response.

L1.42

Introduction to Abaqus

Drop test of a cell phone

Overview of Abaqus/Standard and Abaqus/Explicit

•

Abaqus/Explicit (cont’d)

• Also a powerful tool for quasi static metal forming simulations.

• Annealing is available for multistep forming simulations

L1.43

Introduction to Abaqus

Rolling of a symmetric I-section

Overview of Abaqus/Standard and Abaqus/Explicit

•

Multiphysics with Abaqus/Explicit

• Thermal-mechanical analysis • Fully coupled: Explicit algorithms for both the mechanical and thermal responses • Can include adiabatic heating effects • Structural-acoustic analysis • Fluid-structure interaction adiabatic

Introduction to Abaqus

fully coupled temperature-displacement Two-stage forging, using ALE — contours of temperature

L1.44

L1.45

Overview of Abaqus/Standard and Abaqus/Explicit

•

Special features of Abaqus/Explicit: ALE

• Adaptive meshing using ALE techniques allows the robust solution of highly nonlinear problems.

• Mesh adaptivity is based on solution variables as well as minimum element distortion. • Elements concentrate in areas where they are needed. • Adaptation is based on boundary curvature.

Bulk metal forming High speed impact Introduction to Abaqus

L1.46

Overview of Abaqus/Standard and Abaqus/Explicit

•

Special features of Abaqus/Explicit: Coupled Eulerian-Lagrangian (CEL)

• Define a domain in which material can flow for an Eulerian analysis • Flow problems • Structural problems with extreme deformation Eulerian mesh rod material

Introduction to Abaqus

L1.47

Overview of Abaqus/Standard and Abaqus/Explicit

•

Comparing Abaqus/Standard and Abaqus/Explicit Abaqus/Standard

• A general-purpose finite element program.

• Nonlinear problems require iterations.

• Can solve for true static equilibrium in structural simulations.

• Provides a large number of capabilities for analyzing many different types of problems.

• Nonstructural applications.

• Coupled or uncoupled response.

Abaqus/Explicit

• A general-purpose finite element program for explicit dynamics. • Solution procedure does not require iteration.

• Solves highly discontinuous high speed dynamic problems efficiently.

• Coupled-field analyses include: • Thermal-mechanical • Structural-acoustic • FSI

Introduction to Abaqus

Abaqus Conventions

Abaqus Conventions

•

Units

• Abaqus uses no inherent set of units.

• It is the user’s responsibility to use consistent units.

• Example: • N, kg, m, s or • N, 10 3 kg, mm, s etc. Common systems of consistent units

Introduction to Abaqus

L1.49

Abaqus Conventions

• Example: Properties of mild steel at room temperature

Quantity

Conductivity Density Elastic modulus Specific heat Yield stress

U.S. units

28.9 Btu/ft hr ºF 2.4 Btu/in hr ºF 15.13 slug/ft 3 (lbf s 2 /ft 4 ) 0.730 × 10 −3 lbf s 2 /in 4 0.282 lbm/in 3 30 × 10 6 psi 0.11 Btu/lbm ºF 30 × 10 3 psi

SI units

50 W/m ºC 7800 kg/m 3 207 × 10 9 Pa 460 J/kg ºC 207 × 10 6 Pa

L1.50

Introduction to Abaqus

L1.51

Abaqus Conventions

•

Time measures

• Abaqus keeps track of both

total time

each analysis step.

in an analysis and

step time

for • Time is physically meaningful for some analysis procedures, such as transient dynamics.

• Time is not physically meaningful for some procedures. In rate independent, static procedures “time” is just a convenient, monotonically increasing measure for incrementing loads.

Introduction to Abaqus

L1.52

Abaqus Conventions

•

Coordinate systems

• For

boundary conditions

and

point loads

, the default coordinate system is the rectangular Cartesian system.

• Alternative local rectangular, cylindrical, and spherical systems can be defined. • These local directions

do not

rotate with the material in large displacement analyses.

local rectangular coordinate system with YSYMM boundary conditions Boundary conditions on a skew edge

Introduction to Abaqus

L1.53

Abaqus Conventions

• For

material directions

(i.e., directions associated with an element’s material or integration points) the default coordinate system depends on the element type: • Solid elements use global rectangular Cartesian system.

Default material directions for solid elements • Shell and membrane elements use a projection of the global Cartesian system onto the surface.

Introduction to Abaqus

Default material directions for shell and membrane elements

Abaqus Conventions

• Alternative rectangular, cylindrical, and spherical coordinate systems may be defined.

• Affects input: anisotropic material directions.

• Affects output: stress/strain output directions.

• Local material directions

rotate

with the material in large-displacement analyses.

2 1

Introduction to Abaqus

L1.54

L1.55

Abaqus Conventions

•

Degrees of freedom

• Primary solution variables at the nodes.

• Available nodal degrees of freedom depend on the element type.

• Each degree of freedom is labeled with a number: 1=

x

-displacement, 2=

y

-displacement, 11=temperature, etc.

Introduction to Abaqus

Documentation

Documentation

•

Primary reference materials

• • • • All documentation is available in HTML and PDF format

Abaqus Analysis User’s Manual Abaqus/CAE User’s Manual Abaqus Example Problems Manual

• • •

Abaqus Benchmarks Manual Abaqus Verification Manual Abaqus Keywords Reference Manual

• •

Abaqus User Subroutines Reference Manual Abaqus Theory Manual

• The documentation is available through the

Help

menu on the main menu bar of Abaqus/CAE.

Introduction to Abaqus

L1.57

Documentation

•

Additional reference materials

•

Abaqus Installation and Licensing Guide

(print version available) • Installation instructions •

Abaqus Release Notes

• Explains changes since previous release • •

Advanced lecture notes on various topics Tutorials

• • (print only)

Getting Started with Abaqus: Interactive Edition Getting Started with Abaqus: Keywords Edition

•

Programming

• Scripting and GUI Toolkit manuals •

SIMULIA home page www.simulia.com

Introduction to Abaqus

L1.58

Documentation

•

HTML documentation

• The documentation for Abaqus is organized into a collection, with manuals grouped by function.

• Viewed through a web browser. • Can search entire collection or individual manuals

L1.59

Introduction to Abaqus

L1.60

Documentation

•

Searching the documentation

• Enter one or more search terms in the search field Terms in the search field: Appear in any order May or may not be adjacent Appear within the proximity criterion (default is a single section) The table of contents entry is highlighted The text frame displays the corresponding section

Introduction to Abaqus

Documentation

•

Searching the documentation (cont’d)

• Use quotes to search for exact strings

L1.61

Introduction to Abaqus

Documentation

•

Advanced search

• Advanced search allows you to control the proximity criterion

L1.62

Introduction to Abaqus

Documentation

•

Advanced search (cont’d)

L1.63

Introduction to Abaqus

Abaqus Environment Settings

L1.65

Abaqus Environment Settings

• •

The Abaqus environment settings allow you to control various aspects of an Abaqus job’s execution.

• For example, setting a directory to be used for scratch files, changing the default memory settings, etc.

Environment settings hierarchy

• Abaqus environment settings are processed in the following order: • The host-level environment settings in the

site

directory in the

abaqus

account directory. These settings are applied to all Abaqus jobs run on the designated computer.

• The user-level environment settings in the home directory. These settings are applied to all Abaqus jobs run in your account.

• The job-level environment settings in the current working directory. These settings are applied to only the designated Abaqus job.

• The host-level environment settings are included in the release.

• You can create an environment file

abaqus_v6.env

directory and/or current directory.

in your home

Introduction to Abaqus

L1.66

Abaqus Environment Settings

•

Note:

The value of the SCRATCH parameter is platform specific.

• On UNIX platforms the default value is the value of the

$TMPDIR

environment variable or

/tmp

if this variable is not defined. For example,

scratch="/tmp"

• On Windows platforms the default value is the value of the

%TEMP%

environment variable or

\TEMP

if this variable is not defined. For example,

scratch="c:\\temp"

•

For information on environment file settings refer to:

“Using the Abaqus environment settings,” Section 3.3.1 of the Abaqus Analysis User's Manual.

Introduction to Abaqus

Abaqus Fetch Utility

L1.68

Abaqus Fetch Utility

• •

The Abaqus fetch utility allows you to extract sample Abaqus files that are provided with each release.

• Files that may be extracted include input files, journal files, model databases, etc. corresponding to the Abaqus Example, Benchmark, and Verification problems.

• The utility may also be used to extract scripts that create complete models corresponding to each workshop of this course.

• The “answer” script name is noted at the end of each workshop.

To use the fetch utility enter the following command at the operating system prompt: abaqus fetch job=

filename

where

abaqus

is the command used to run Abaqus on your system.

• For example, Abaqus release 6.10-1 it might be aliased to

abq6101

.

Introduction to Abaqus

Abaqus/CAE Checklist

Abaqus/CAE Checklist

Must Have Must Have Must Have Must Have Must Have Must Have Usually Need Usually Need Must Have Must Have Parts Materials Sections Section Assignments Assembly (Instances) Steps (after Initial) BCs (Boundary Conditions) Loads Mesh Jobs At least one At least one At least one Made at the part level (container) At least one part Initial created for you Can be in Initial Step In Steps after the Initial Can be done on part or assembly To actually run the analysis

L1.70

Introduction to Abaqus

Working with the Model Tree

Working with the Model Tree

•

The Model Tree is a convenient tool for navigating and managing your models and analysis results.

• The Model Tree provides a visual description of the hierarchy of items in a model.

• The arrangement of the containers and items in the Model Tree reflects the order in which you are likely to create your model. • A similar logic governs the order of modules in the module menu —you create parts before you create the assembly, and you create steps before you create loads.

Introduction to Abaqus

L1.72

Working with the Model Tree

• Example: The following figure shows a suggested order to create the cantilever beam model .

(

Note:

This order is not unique.)

L1.73

Introduction to Abaqus

L1.74

Working with the Model Tree

• Alternatively, follow the order of modules in the module menu to create the model.

Part Property Assembly

• Create the part geometry • Define materials • Define and assign sections • Position the part for initial configuration.

to parts or regions

Step

• Define analysis steps and output requests • Mesh the part

Mesh Interaction

• Not applicable for this example

Job

• Submit, manage, and monitor analysis jobs

Load

• Apply loads and BCs to regions or named sets; and assign them to steps in the analysis history

Visualization

• Examine results

Introduction to Abaqus

Workshop 1: Linear Static Analysis of a Cantilever Beam

L1.76

Workshop 1: Linear Static Analysis of a Cantilever Beam

•

Workshop tasks

• Follow detailed instructions to create a simple cantilever beam model using the Abaqus/CAE modules.

• Submit a job for analysis.

• View the analysis results.

Introduction to Abaqus