University of Alberta - ANSYS Tutorials

ANSYS is a general purpose finite element modeling package for numerically solving a wide variety of mechanical

problems. These problems include: static/dynamic structural analysis (both linear and non-linear), heat transfer and

fluid problems, as well as acoustic and electromagnetic problems. Most of these tutorials have been created using

ANSYS 7.0, therefore, make note of small changes in the menu structure if you are using an older or newer version.

This web site has been organized into the following six sections.

n ANSYS Utilities

An introduction to using ANSYS. This includes a quick explanation of the stages of analysis, how to start

ANSYS, the use of the windows in ANSYS, convergence testing, saving/restoring jobs, and working with

Pro/E.

n Basic Tutorials

Detailed tutorials outlining basic structural analysis using ANSYS. It is recommended that you complete

these tutorials in order as each tutorial builds upon skills taught in previous examples.

n Intermediate Tutorials

Complex skills such as dynamic analysis and nonlinearities are explored in this section. It is recommended

that you have completed the Basic Tutorials prior to attempting these tutorials.

n Advanced Tutorials

Advanced skills such as substructuring and optimization are explored in this section. It is recommended that

you have completed the Basic Tutorials prior to attempting these tutorials.

n Postprocessing Tutorials

Postprocessing tools available in ANSYS such as X-sectional views of the geometry are shown in this

section. It is recommended that you have completed the Basic Tutorials prior to attempting these tutorials.

n Command Line Files

Example problems solved using command line coding only, in addition to several files to help you to

generate your own command line files.

ANSYS Utilities

An introduction to using ANSYS, including a quick explanation of the stages of analysis, how to start ANSYS, and

the use of the windows in ANSYS, and using Pro/ENGINEER with ANSYS.

l Introduction to Finite Element Analysis

A brief introduction of the 3 stages involved in finite element analysis.

l Starting up ANSYS

How to start ANSYS using windows NT and Unix X-Windows.

l ANSYS Environment

An introduction to the windows used in ANSYS

l ANSYS Interface

An explanation of the Graphic User Interface (GUI) in comparison to the command file approach.

l Convergence Testing

This file can help you to determine how small your meshing elements need to be before you can trust the

solution.

l Saving/Restoring Jobs

Description of how to save your work in ANSYS and how to resume a previously saved job.

l ANSYS Files

Definitions of the different files created by ANSYS.

l Printing Results

Saving data and figures generated in ANSYS.

l Working with Pro Engineer

A description of how to export geometry from Pro/E into ANSYS.

Basic Tutorials

The following documents will lead you through several example problems using ANSYS. ANSYS 7.0 was used to

create some of these tutorials while ANSYS 5.7.1 was used to create others, therefore, if you are using a different

version of ANSYS make note of changes in the menu structure. Complete these tutorials in order as each tutorial will

build on skills taught in the previous example.

l Two Dimensional Truss

Basic functions will be shown in detail to provide you with a general knowledge of how to use ANSYS. This

tutorial should take approximately an hour and a half to complete.

l Bicycle Space Frame

Intermediate ANSYS functions will be shown in detail to provide you with a more general understanding of

how to use ANSYS. This tutorial should take approximately an hour and a half to complete.

l Plane Stress Bracket

Boolean operations, plane stress and uniform pressure loading will be introduced in the creation and analysis of

this 2-Dimensional object.

l Solid Modeling

This tutorial will introduce techniques such as filleting, extrusion, copying and working plane orienation to

create 3-Dimensional objects.

Intermediate Tutorials

The majority of these examples are simple verification problems to show you how to use the intermediate techniques

in ANSYS. You may be using a different version of ANSYS than what was used to create these tutorials, therefore,

make note of small changes in the menu structure. These tutorials can be completed in any order, however, it is

expected that you have completed the Basic Tutorials before attempting these.

l Effect of Self Weight

Incorporating the weight of an object into the finite element analysis is shown in this simple cantilever beam

example.

l Distributed Loading

The application of distributed loads and the use of element tables to extract data is expalined in this tutorial.

l NonLinear Analysis

A large moment is applied to the end of a cantilever beam to explore Geometric Nonlinear behaviour (large

deformations). There is also an associated tutorial for an explanation of the Graphical Solution Tracking

(GST) plot.

l Buckling

In this tutorial both the Eigenvalue and Nonlinear methods are used to solve a simple buckling problem.

l NonLinear Materials

The purpose of the tutorial is to describe how to include material nonlinearities in an ANSYS model.

l Dynamic Analysis

These tutorial explore the dynamic analyis capabilities of ANSYS. Modal, Harmonic, and Transient

Analyses are shown in detail.

l Thermal Examples

Analysis of a pure conduction, a mixed convection/conduction/insulated boundary condition example, and a

transient heat conduction analysis.

Modelling Using Axisymmetry

Utilizing axisymmetry to model a 3-D structure in 2-D to reduce computational time.

Advanced Tutorials

The majority of these examples are simple verification problems to show you how to use the more advanced

techniques in ANSYS. You may be using a different version of ANSYS than what was used to create these tutorials,

therefore, make note of small changes in the menu structure. These tutorials can be completed in any order, however,

it is expected that you have completed the Basic Tutorials.

l Springs and Joints

The creation of models with multiple elements types will be explored in this tutorial. Additionally, elements

COMBIN7 and COMBIN14 will be explained as well as the use of parameters to store data.

l Design Optimization

The use of Design Optimization in ANSYS is used to solve for unknown parameters of a beam.

l Substructuring

The use of Substructuring in ANSYS is used to solve a simple problem.

l Coupled Structural/Thermal Analysis

The use of ANSYS physics environments to solve a simple structural/thermal problem.

l Using P-Elements

The stress distribution of a model is solved using p-elements and compared to h-elements.

l Melting Using Element Death

Using element death to model a volume melting.

l Contact Elements

Model of two beams coming into contact with each other.

l ANSYS Parametric Design Language

Design a truss using parametric variables.

Postprocessing Tutorials

These tutorials were created to show some of the tools available in ANSYS for postprocessing. You may be using a

different version of ANSYS than what was used to create these tutorials, therefore, make note of small changes in the

menu structure. These tutorials can be completed in any order, however, it is expected that you have completed the

Basic Tutorials.

l Viewing Cross Sectional Results

The method to view cross sectional results for a volume are shown in this tutorial.

l Advanced X-Sectional Results: Using Paths to Post Process Results

The purpose of this tutorial is to create and use 'paths' to provide extra detail during post processing.

l Data Plotting: Using Tables to Post Process Results

The purpose of this tutorial is to outline the steps required to plot results using tables, a special type of array.

l Changing Graphical Properties

This tutorial outlines some of the basic graphical changes that can be made to the main screen and model.

Command Line Files

The following files should help you to generate your own command line files.

l Creating Command Files

Directions on generating and running command files.

l ANSYS Command File Programming Features

This file shows some of the commonly used programming features in the ANSYS command file language

known as ADPL (ANSYS Parametric Design Language). Prompting the user for parameters, performing

calculations with paramaters and control structures are illustrated.

The following files include some example problems that have been created using command line coding.

Basic Tutorials This set of command line codes are from the Basic Tutorial section.

Intermediate Tutorials This set of command line codes are from the Intermediate Tutorial section.

Advanced Tutorials This set of command line codes are from the Advanced Tutorial section.

PostProc Tutorials This set of command line codes are from the PostProc Tutorial section.

Radiation Analysis A simple radiation heat transfer between concentric cylinders.

Introduction

ANSYS is a general purpose finite element modeling package for numerically solving a wide variety of mechanical problems. These

problems include: static/dynamic structural analysis (both linear and non-linear), heat transfer and fluid problems, as well as acoustic and

electro-magnetic problems.

In general, a finite element solution may be broken into the following three stages. This is a general guideline that can be used for setting

up any finite element analysis.

1. Preprocessing: defining the problem; the major steps in preprocessing are given below:

m Define keypoints/lines/areas/volumes

m Define element type and material/geometric properties

m Mesh lines/areas/volumes as required

The amount of detail required will depend on the dimensionality of the analysis (i.e. 1D, 2D, axi-symmetric, 3D).

2. Solution: assigning loads, constraints and solving; here we specify the loads (point or pressure), contraints (translational and

rotational) and finally solve the resulting set of equations.

3. Postprocessing: further processing and viewing of the results; in this stage one may wish to see:

m Lists of nodal displacements

m Element forces and moments

m Deflection plots

m Stress contour diagrams

Starting up ANSYS

Large File Sizes

ANSYS can create rather large files when running and saving; be sure that your local drive has space for it.

Getting the Program Started

In the Mec E 3-3 lab, there are two ways that you can start up ANSYS:

1. Windows NT application

2. Unix X-Windows application

Windows NT Start Up

Starting up ANSYS in Windows NT is simple:

l Start Menu

l Programs

l ANSYS 5.7

l Run Interactive Now

Unix X-Windows Start Up

Starting the Unix version of ANSYS involves a few more steps:

l in the task bar at the bottom of the screen, you should see something labeled X-Win32. If you don't see this minimized program,

you can may want to reboot the computer, as it automatically starts this application when booting.

l right click on this menu and selection Sessions and then select Mece.

l you will now be prompted to login to GPU... do this.

l once the Xwindows emulator has started, you will see an icon at the bottom of the screen that looks like a paper and pencil; don't

select this icon, but rather, click on the up arrow above it and select Terminal

l a terminal command window will now start up

l in that window, type xansys57

l at the UNIX prompt and a small launcher menu will appear.

l select the Run Interactive Now menu item.

ANSYS 7.0 Environment

The ANSYS Environment for ANSYS 7.0 contains 2 windows: the Main Window and an Output Window. Note that this is somewhat different from the

previous version of ANSYS which made use of 6 different windows.

Main Window

Within the Main Window are 5 divisions:

a. Utility Menu

The Utility Menu contains functions that are available throughout the ANSYS session, such as file controls, selections, graphic controls and

parameters.

b. Input Lindow

The Input Line shows program prompt messages and allows you to type in commands directly.

c. Toolbar

The Toolbar contains push buttons that execute commonly used ANSYS commands. More push buttons can be added if desired.

d. Main Menu

The Main Menu contains the primary ANSYS functions, organized by preprocessor, solution, general postprocessor, design optimizer. It is from

this menu that the vast majority of modelling commands are issued. This is where you will note the greatest change between previous versions

of ANSYS and version 7.0. However, while the versions appear different, the menu structure has not changed.

e. Graphics Window

The Graphic Window is where graphics are shown and graphical picking can be made. It is here where you will graphically view the model in

its various stages of construction and the ensuing results from the analysis.

2. Output Window

The Output Window shows text output from the program, such as listing of data etc. It is usually positioned behind the main window and can de put to

the front if necessary.

ANSYS Interface

Graphical Interface vs. Command File Coding

There are two methods to use ANSYS. The first is by means of the graphical user interface or GUI. This method follows the conventions

of popular Windows and X-Windows based programs.

The second is by means of command files. The command file approach has a steeper learning curve for many, but it has the advantage that

an entire analysis can be described in a small text file, typically in less than 50 lines of commands. This approach enables easy model

modifications and minimal file space requirements.

The tutorials in this website are designed to teach both the GUI and the command file approach, however, many of you will find the

command file simple and more efficient to use once you have invested a small amount of time into learning the code.

For information and details on the full ANSYS command language, consult:

Help > Table of Contents > Commands Manual.

FEM Convergence Testing

Introduction

A fundamental premise of using the finite element procedure is that the body is sub-divided up into small discrete regions known as finite

elements. These elements defined by nodes and interpolation functions. Governing equations are written for each element and these

elements are assembled into a global matrix. Loads and constraints are applied and the solution is then determined.

The Problem

The question that always arises is: How small do I need to make the elements before I can trust the solution?

What to do about it...

In general there are no real firm answers on this. It will be necessary to conduct convergence tests! By this we mean that you begin with a

mesh discretization and then observe and record the solution. Now repeat the problem with a finer mesh (i.e. more elements) and then

compare the results with the previous test. If the results are nearly similar, then the first mesh is probably good enough for that particular

geometry, loading and constraints. If the results differ by a large amount however, it will be necessary to try a finer mesh yet.

The Consequences

Finer meshes come with a cost however: more calculational time and large memory requirements (both disk and RAM)! It is desired to

find the minimum number of elements that give you a converged solution.

Beam Models

For beam models, we actually only need to define a single element per line unless we are applying a distributed load on a given frame

member. When point loads are used, specifying more that one element per line will not change the solution, it will only slow the

calculations down. For simple models it is of no concern, but for a larger model, it is desired to minimize the number of elements, and thus

calculation time and still obtain the desired accuracy.

General Models

In general however, it is necessary to conduct convergence tests on your finite element model to confirm that a fine enough element

discretization has been used. In a solid mechanics problem, this would be done by creating several models with different mesh sizes and

comparing the resulting deflections and stresses, for example. In general, the stresses will converge more slowly than the displacement, so

it is not sufficient to examine the displacement convergence.

ANSYS: Saving and Restoring Jobs

Saving Your Job

It is good practice to save your model at various points during its creation. Very often you will get to a point in the modeling where things

have gone well and you like to save it at the point. In that way, if you make some mistakes later on, you will at least be able to come back

to this point.

To save your model, select Utility Menu Bar -> File -> Save As Jobname.db. Your model will be saved in a file called

jobname.db, where jobname is the name that you specified in the Launcher when you first started ANSYS.

It is a good idea to save your job at different times throughout the building and analysis of the model to backup your work incase of a

system crash or other unforseen problems.

Recalling or Resuming a Previously Saved Job

Frequently you want to start up ANSYS and recall and continue a previous job. There are two methods to do this:

1. Using the Launcher...

m In the ANSYS Launcher, select Interactive... and specify the previously defined jobname.

m Then when you get ANSYS started, select Utility Menu -> File -> Resume Jobname.db .

m This will restore as much of your database (geometry, loads, solution, etc) that you previously saved.

2. Or, start ANSYS and select Utitily Menu -> File -> Resume from... and select your job from the list that appears.

ANSYS Files

Introduction

A large number of files are created when you run ANSYS. If you started ANSYS without specifying a jobname, the name of all the files

created will be FILE.* where the * represents various extensions described below. If you specified a jobname, say Frame, then the

created files will all have the file prefix, Frame again with various extensions:

frame.db

Database file (binary). This file stores the geometry, boundary conditions and any solutions.

frame.dbb

Backup of the database file (binary).

frame.err

Error file (text). Listing of all error and warning messages.

frame.out

Output of all ANSYS operations (text). This is what normally scrolls in the output window during an ANSYS session.

frame.log

Logfile or listing of ANSYS commands (text). Listing of all equivalent ANSYS command line commands used during the current

session.

etc...

Depending on the operations carried out, other files may have been written. These files may contain results, etc.

What to save?

When you want to clean up your directory, or move things from the /scratch directory, what files do you need to save?

l If you will always be using the GUI, then you only require the .db file. This file stores the geometry, boundary conditions and any

solutions. Once the ANSYS has started, and the jobname has been specified, you need only activate the resume command to

proceed from where you last left off (see Saving and Restoring Jobs).

l If you plan on using ANSYS command files, then you need only store your command file and/or the log file. This file contains a

complete listing of the ANSYS commands used to get you model to its current point. That file may be rerun as is, or edited and

rerun as desired (Command File Creation and Execution).

If you plan to use the command mode of operation, starting with an existing log file, rename it first so that it does not get overwritten

or added to, from another ANSYS run.

Printing and Plotting ANSYS Results to a File

Printing Text Results to a File

ANSYS produces lists and tables of many types of results that are normally displayed on the screen. However, it is often desired to save

the results to a file to be later analyzed or included in a report.

1. Stresses: instead of using 'Plot Results' to plot the stresses, choose 'List Results'. Select 'Elem Table Data', and choose what you

want to list from the menu. You can pick multiple items. When the list appears on the screen in its own window, Select 'File'/'Save

As...' and give a file name to store the results.

2. Any other solutions can be done in the same way. For example select 'Nodal Solution' from the 'List Results' menu, to get

displacements.

3. Preprocessing and Solution data can be listed and saved from the 'List' menu in the 'Utility Menu bar'. Save the resulting list in the

same way described above.

Plotting of Figures

There are two major routes to get hardcopies from ANSYS. The first is a quick a raster-based screen dump, while the second is a scalable

vector plot.

1.0 Quick Image Save

When you want to quickly save an image of the entire screen or the current 'Graphics window', select:

l 'Utility menu bar'/'PlotCtrls'/'Hard Copy ...'.

l In the window that appears, you will normally want to select 'Graphics window', 'Monochrome', 'Reverse Video', 'Landscape' and

'Save to:'.

l Then enter the file name of your choice.

l Press 'OK'

This raster image file may now be printed on a PostScript printer or included in a document.

2.0 Better Quality Plots

The second method of saving a plot is much more flexible, but takes a lot more work to set up as you'll see...

Redirection

Normally all ANSYS plots are directed to the plot window on the screen. To save some plots to a file, to be later printed or included in a

document or what have you, you must first 'redirect' the plots to a file by issuing:

'Utility menu bar'/'PlotCtrls'/'Redirect Plots'/'To File...'.

Type in a filename (e.g.: frame.pic) in the 'Selection' Window.

Now issue whatever plot commands you want within ANSYS, remembering that the plots will not be displayed to the screen, but rather

they will be written to the selected file. You can put as many plots as you want into the plot file. When you are finished plotting what you

want to the file, redirect plots back to the screen using:

'Utility menu bar'/'PlotCtrls'/'Redirect Plots'/'To Screen'.

Display and Conversion

The plot file that has been saved is stored in a proprietary file format that must be converted into a more common graphic file format like

PostScript, or HPGL for example. This is performed by running a separate program called display. To do this, you have a couple of

options:

1. select display from the ANSYS launcher menu (if you started ANSYS that way)

2. shut down ANSYS or open up a new terminal window and then type display at the Unix prompt.

Either way, a large graphics window will appear. Decrease the size of this window, because it most likely covers the window in which you

will enter the display plotting commands. Load your plot file with the following command:

file,frame,pic

if your plot file is 'plots.pic'. Note that although the file is 'plots.pic' (with a period), Display wants 'plots,pic'(with a comma). You can

display your plots to the graphics window by issuing the command like

plot,n

where n is plot number. If you plotted 5 images to this file in ANSYS, then n could be any number from 1 to 5.

Now that the plots have been read in, they may be saved to printer files of various formats:

1. Colour PostScript: To save the images to a colour postscript file, enter the following commands in display:

pscr,color,2

/show,pscr

plot,n

where n is the plot number, as above. You can plot as many images as you want to postscript files in this manner. For subsequent

plots, you only require the plot,n command as the other options have now been set. Each image is plotted to a postscript file

such as pscrxx.grph, where xx is a number, starting at 00.

Note: when you import a postscript file into a word processor, the postscript image will appear as blank box. The printer

information is still present, but it can only be viewed when it's printed out to a postscript printer.

Printing it out: Now that you've got your color postscript file, what are you going to do with it? Take a look here for instructions

on colour postscript printing at a couple of sites on campus where you can have your beautiful stress plot plotted to paper,

overheads or even posters!

2. Black & White PostScript: The above mentioned colour postscript files can get very large in size and may not even print out on

the postscript printer in the lab because it takes so long to transfer the files to the printer and process them. A way around this is to

print them out in a black and white postscript format instead of colour; besides the colour specifications don't do any good for the

black and white lab printer anyways. To do this, you set the postscript color option to '3', i.e. and then issue the other commands as

before

pscr,color,3

/show,pscr

plot,n

Note: when you import a postscript file into a word processor, the postscript image will appear as blank box. The printer

information is still present, but it can only be viewed when it's printed out to a postscript printer.

3. HPGL: The third commonly used printer format is HPGL, which stands for Hewlett Packard Graphics Language. This is a compact

vector format that has the advantage that when you import a file of this type into a word processor, you can actually see the image

in the word processor! To use the HPGL format, issue the following commands:

/show,hpgl

plot,n

Final Steps

It is wise to rename these plot files as soon as you leave display, for display will overwrite the files the next time it is run. You may want to rename the postscript files with an '.eps' extension to indicate that they are encapsulated postscript images. In a

similar way, the HPGL printer files could be given an '.hpgl' extension. This renaming is done at the Unix commmand line (the 'mv'

command).

A list of all available display commands and their options may be obtained by typing:

help

When complete, exit display by entering

finish