Tutorial ANSYS Universidad de Alberta

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University of Alberta - ANSYS Tutorials

UofA ANSYS Tutor ia lANSYS

U TI L I T I E SBASI C

TUTORI ALSI NTERMEDIATE

TUTORI ALSADVANCEDTUTORI ALS

POSTPROC.TUTORI ALS

COMMANDLI NE FI LES

I n d e x

C o n t r i b u t i o n s

C o m m e n t s

MecE 563

Mechan ica l Eng ineer in g

U n i ve r s it y o f A l b e r t a

ANSYS I nc.

Copyright 2001

University of Alberta


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

s 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.

s 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.

s 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.

s 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.

s 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.

s Command Line Files

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

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generate your own command line files.

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U of A ANSYS Tutorials - ANSYS Utilities





POSTPROC.TUTORI ALS

COMMANDLI NE FI LES

I n t r o d u c t i o n

S tar t i ng u p ANSYS

ANSYS Env i ro nm ent

ANSYS In te r face

Converg ence Test ing

Sa v i n g / R e st o r i n g Jo b s

ANSYS Files

Pr in t i ng Resu l t s

W o r k i n g w i t h Pr o / E

I n d e x


C o m m e n t s

MecE 563



ANSYS I nc.

ANSYS Utilities

An introduction to using ANSYS, including a quick explanation of the stages of analysis, how to start ANSYS, andthe use of the windows in ANSYS, and using Pro/ENGINEER with ANSYS.

q Introduction to Finite Element Analysis

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

q Starting up ANSYS

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

q ANSYS Environment

An introduction to the windows used in ANSYS

q ANSYS Interface

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

q Convergence Testing

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

q Saving/Restoring Jobs

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

q ANSYS Files

Definitions of the different files created by ANSYS.

q Printing Results

Saving data and figures generated in ANSYS.

q Working with Pro Engineer

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

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U of A ANSYS Tutorials - ANSYS Utilities

Copyright 2001


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U of A ANSYS Tutorials - Basic Tutorials Index





POSTPROC.TUTORI ALS

COMMANDLI NE FI LES

T w o D i m e n s i o n a l T ru ss

B icyc le Space Fram e

P lane S t ress B racket

Mode l ing Too ls

So l id Mode l ing

I n d e x


C o m m e n t s

MecE 563



ANSYS I nc.

Copyright 2001


Basic Tutorials

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

q Two Dimensional Truss

Basic functions will be shown in detail to provide you with a general knowledge of how to use ANSYS. Thistutorial should take approximately an hour and a half to complete.

q 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.

q Plane Stress Bracket

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

this 2-Dimensional object.

q Solid Modeling

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

create 3-Dimensional objects.

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U of A ANSYS Tutorials - Basic Tutorials Index

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U of A ANSYS Tutorials - Intermediate Tutorials





POSTPROC.TUTORI ALS

COMMANDLI NE FI LES

Ef fect o f Se lf W eigh t

D i s t r i b u t e d L o a d i n g

NonL inear Ana lys i s

So lu t ion T rack ing

Buck l ing

NonL inear Mater ia l s

D yn a m i c - M o d a l

D yn a m i c - H a rm o n i c

Dynamic - T rans ien t

Thermal -Conduct ion

T h e rm a l -M i xe d B n d ry

Trans ien t Heat

A x i sym m e t r i c

I n d e x


C o m m e n t s

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Intermediate Tutorials

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

q Effect of Self Weight

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

q Distributed Loading

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

q NonLinear AnalysisA 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.

q Buckling

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

q NonLinear Materials

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

q Dynamic Analysis

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

Analyses are shown in detail.

q Thermal Examples

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

transient heat conduction analysis.

q Modelling Using Axisymmetry

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U of A ANSYS Tutorials - Intermediate Tutorials

ANSYS I nc.

Copyright 2001


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

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Advanced Tutorials





POSTPROC.TUTORI ALS

COMMANDLI NE FI LES

Spr ings and Jo in t s

Des ign Opt im iza t ion

S u b s t ru c t u r i n g

Coupled Field

p-E lement

Element Death

Contact E lement s

APDL

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ANSYS I nc.

Copyright 2001


Advanced Tutorials

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

q Springs and Joints

The creation of models with multiple elements types will be explored in this tutorial. Additionally, elementsCOMBIN7 and COMBIN14 will be explained as well as the use of parameters to store data.

q Design Optimization

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

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

q Coupled Structural/Thermal Analysis

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

q Using P-Elements

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

q Melting Using Element DeathUsing element death to model a volume melting.

q Contact Elements

Model of two beams coming into contact with each other.

q ANSYS Parametric Design Language

Design a truss using parametric variables.

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Advanced Tutorials

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Post-Processing Tutorials





POSTPROC.TUTORI ALS

COMMANDLI NE FI LES

X-Sect iona l Resu l t s

Advanced X -Sec Res

Data P lo t t i ng

Graph ica l Proper t i es

I n d e x


C o m m e n t s

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ANSYS I nc.

Copyright 2001


Postprocessing Tutorials

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

q Viewing Cross Sectional Results

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

q 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.

q 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.

q Changing Graphical Properties

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

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Post-Processing Tutorials

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U of A ANSYS Tutorials Command Line Files


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U of A ANSYS Tutorials - Command Line Files





POSTPROC.TUTORI ALS

COMMANDLI NE FI LES

Creat ing F i l es

Features

Bas ic Tu tor ia l s

I n t e rm e d i a t e T u t o r i a ls

Advanced Tutor ia l s

PostP roc Tutor ia l s

Rad ia t ion

I n d e x


C o m m e n t s

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ANSYS I nc.

Copyright 2001


Command Line Files

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

q Creating Command Files

Directions on generating and running command files.

q 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.

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U of A ANSYS Tutorials - Command Line Files

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Introduction


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Introduction

UofA ANSYS Tuto r ia l ANSYS

UT IL IT I ES

BASIC

TUTORIALS

I NTERMEDI ATE

TUTORIALS

ADVANCED

TUTORIALS

POSTPROC.

TUTORIALS

COMMAND

LIN E FI LES

PRINTABLE

VERSI ON


Star t ing up ANSYS

ANSYS Env i ronment

ANSYS I nter face

Convergence Test ing

Sav ing / Resto r i ng J obs

ANSYS Fi les

P r i n t i ng Res u l t s

W o r k i n g w i t h P r o / E

I n d e x

Con t r i bu t i ons

C o m m e n t s

MecE 563

Mechanica l Engineer ing

Un i v e r s it y o f A l be r ta

ANSYS I nc .

Copyright 2001


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:

r Define keypoints/lines/areas/volumes

r Define element type and material/geometric properties

r 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 androtational) 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:

r Lists of nodal displacements

r Element forces and moments

r Deflection plots

r Stress contour diagrams

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Introduction


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t oduct o

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Starting up ANSYS


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g p


UT IL IT I ES

BASIC

TUTORIALS

I NTERMEDI ATE

TUTORIALS

ADVANCED

TUTORIALS

POSTPROC.

TUTORIALS

COMMAND

LIN E FI LES

PRINTABLE

VERSI ON


Star t ing up ANSYS

ANSYS Env i ronment

ANSYS I nter face



ANSYS Fi les



I n d e x


C o m m e n t s

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ANSYS I nc .

Copyright 2001


Starting up ANSYS

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:

q Start Menu

q Programs

q ANSYS 5.7

q Run Interactive Now

Unix X-Windows Start Up

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

q 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.

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

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

q 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

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q a terminal command window will now start up

q in that window, type xansys57

q at the UNIX prompt and a small launchermenu will appear.

q select the Run Interactive Now menu item.

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ANSYS Environment


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UofA ANSYS Tutor ia l ANSYS

U T I L I T I E S

BASIC

TUTORI ALS

I NTERMEDI ATE

TUTORI ALS

ADVANCED

TUTORI ALS

POSTPROC.

TUTORI ALS

COMMAND

LIN E FI LESANSYS 5.7.1

PRINTABLE

VERSI ON

I n t r o d u c t io n

Sta r t i ng up ANSYS

ANSYS Env i ronm ent

ANSYS In te r face


Sav ing / Res to r i ng Jobs

ANSYS Files

Pr i n t i ng Resu l t s

W o r k i n g w i t h Pr o / E

I n d e x


C o m m e n t s

MecE 563

Mechan i ca l Eng ineer i ng

Un i ve rs i t y o f A lbe r ta

ANSYS I nc.

Copyright 2001


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.

1. 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

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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.

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ANSYS Interface


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UT IL IT I ES

BASIC

TUTORIALS

I NTERMEDI ATE

TUTORIALS

ADVANCED

TUTORIALS

POSTPROC.

TUTORIALS

COMMAND

LIN E FI LES

PRINTABLE

VERSI ON


Star t ing up ANSYS

ANSYS Env i ronment

ANSYS I nter face



ANSYS Fi les



I n d e x


C o m m e n t s

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ANSYS I nc .

Copyright 2001


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.

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ANSYS Interface


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Convergence Testing


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UT IL IT I ES

BASIC

TUTORIALS

I NTERMEDI ATE

TUTORIALS

ADVANCED

TUTORIALS

POSTPROC.

TUTORIALS

COMMAND

LIN E FI LES

PRINTABLE

VERSI ON


Star t ing up ANSYS

ANSYS Env i ronment

ANSYS I nter face



ANSYS Fi les



I n d e x


C o m m e n t s

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ANSYS I nc .

Copyright 2001


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 assembledinto 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

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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.

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Saving/Restoring Jobs


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UT IL IT I ES

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TUTORIALS

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TUTORIALS

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TUTORIALS

COMMAND

LIN E FI LES

PRINTABLE

VERSI ON


Star t ing up ANSYS

ANSYS Env i ronment

ANSYS I nter face



ANSYS Fi les



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ANSYS I nc .

Copyright 2001


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 Launcherwhen 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 Resuminga 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...

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

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

r 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.

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ANSYS Files


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UofA ANSYS Tuto r ia lANSYS

UT IL IT I ESBASIC

TUTORIALSI NTERMEDI ATE

TUTORIALSADVANCEDTUTORIALS

POSTPROC.TUTORIALS

COMMANDLIN E FI LES

PRINTABLEVERSI ON


Star t ing up ANSYS

ANSYS Env i ronment

ANSYS I nter face



ANSYS Fi les

Pr i n t i ng Res u l t s


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Copyright 2001


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.outOutput 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?

q 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).

q 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 over-

written or added to, from another ANSYS run.

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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:

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

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

'Save to:'.

q Then enter the file name of your choice.

q 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...

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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 ratherthey 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


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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 instructionson 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 displaywill 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



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UT IL IT I ESBASIC



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Finite Element Method using Pro/ENGINEER and ANSYS

Notes by R.W. Toogood

The transfer of a model from Pro/ENGINEER to ANSYS will be demonstrated here for a simple solid model. Model idealizations such as

shells and beams will not be treated. Also, many modeling options for constraints, loads, mesh control, analysis types will not be covered.

These are fairly easy to figure out once you know the general procedures presented here.

Step 1. Make the part

Use Pro/E to make the part. Things to note are:

r be aware of your model units

r note the orientation of the model (default coordinate system in ANSYS will be the same as in Pro/E)

r IMPORTANT: remove all unnecessary and/or cosmetic features like rounds, chamfers, holes, etc., by suppressing them in Pro/E.

Too much small geometry will cause the mesh generator to create a very fine mesh with many elements which will greatly increase

your solver time. Of course, if the feature is critical to your design, you will want to leave it. You must compromise betweenaccuracy and available CPU resources.

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The figure above shows the original model for this demonstration. This is a model of a short cantilevered bracket that bolts to the wall via

the thick plate on the left end. Model units are inches. A load is applied at the hole in the right end. Some cosmetic features are located on

the top surface and the two sides. Several edges are rounded. For this model, the interest is in the stress distribution around the vertical

slot. So, the plate and the loading hole are removed, as are the cosmetic features and rounds resulting in the "de-featured" geometry shown

below. The model will be constrained on the left face and a uniform load will be applied to the right face.


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Step 2. Create the FEM model

In the pull-down menu at the top of the Pro/E window, select

Applications > Mechanica

An information window opens up to remind you about the units you are using. Press Continue

In the MECHANICA menu at the right, check the box besideFEM Mode and select the command Structure.

A new toolbar appears on the right of the screen that contains icons for creating all the common modeling entities (constraints, loads,

idealizations). All these commands are also available using the command windows that will open on the right side of the screen or in

dialog windows that will open when appropriate.

Notice that a small green coordinate system WCS has appeared. This is how you will specify the directions of constraints and forces.

Other coordinate systems (eg cylindrical) can be created as required and used for the same purpose.

The MEC STRUCT menu appears on the right. Basically, to define the model we proceed down this menu in a top-down manner.Model

is already selected for you which opens the STRC MODEL menu. This is where we specify modeling information. We proceed in a top-

down manner. TheFeatures command allows you to create additional simulation features like datum points, curves, surface regions, and

so on.Idealizations lets you create special modeling entities like shells and beams. The Current CSYS command lets you create or select

an alternate coordinate system for specifying directions of constraints and loads.

Defining Constraints


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For our simple model all we need are constraints loads and a specified material Select


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For our simple model, all we need are constraints, loads, and a specified material. Select

Constraints > New

We can specify constraints on four entity types (basically points, edges, and surfaces). Constraints are organized into constraint sets. Each

constraint set has a unique name (default of the first one is ConstraintSet1) and can contain any number of individual constraints of

different types. Each individual constraint also has a unique name (default of the first one is Constraint1). In the final computed model,

only one set can be included, but this can contain numerous individual constraints.

Select Surface. We are going to fully constrain the left face of the cantilever. A dialog window opens as shown above. Here you can give

a name to the constraint and identify which constraint set it belongs to. Since we elected to create a surface constraint, we now select the

surface we want constrained (push the Surface selection button in the window and then click on the desired surface of the model). The

constraints to be applied are selected using the buttons at the bottom of the window. In general we specify constraints on translation and

rotation for any mesh node that will appear on the selected entity. For each direction X, Y, and Z, we can select one of the four buttons

(Free, Fixed, Prescribed, and Function of Coordinates). For our solid model, the rotation constraints are irrelevant (since nodes of solid

elements do not have this degree of freedom anyway). For beams and shells, rotational constraints are active if specified.

For our model, leave all the translation constraints as FIXED, and select the OKbutton. You should now see some orange symbols on the

left face of the model, along with some text labels that summarize the constraint settings.

Defining Loads


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In the STRC MODEL menu select


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In the STRC MODEL menu select

Loads > New > Surface

The FORCE/MOMENT window opens as shown above. Loads are also organized into named load sets. A load set can contain any

number of individual loads of different types. A FEM model can contain any number of different load sets. For example, in the analysis of

a pressurized tank on a support system with a number of nozzle connections to other pipes, one load set might contain only the internal

pressure, another might contain the support forces, another a temperature load, and more might contain the forces applied at each nozzle

location. These can be solved at the same time, and the principle of superposition used to combine them in numerous ways.

Create a load called "end_load" in the default load set (LoadSet1)

Click on the Surfaces button, then select the right face of the model and middle click to return to this dialog. Leave the defaults for the

load distribution. Enter the force components at the bottom. Note these are relative to the WCS. Then select OK. The load should be

displayed symbolically as shown in the figure below.


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Note that constraint and load sets appear in the model tree. You can select and edit these in the usual way using the right mouse button.

Assigning Materials

Our last job to define the model is to specify the part material. In the STRC MODEL menu, select

Materials > Whole Part

In the library dialog window, select a material and move it to the right pane using the triple arrow button in the center of the window. In an

assembly, you could now assign this material to individual parts. If you select the Edit button, you will see the properties of the chosen

material.

At this point, our model has the necessary information for solution (constraints, loads, material).

Step 3. Define the analysis

Select

Analyses > New


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Specify a name for the analysis, like "ansystest". Select the type (Structural or Modal). Enter a short description. Now select theAdd

buttons beside the Constraints and Loads panes to add ConstraintSet1 and LoadSet1 to the analysis. Now select OK.

Step 4. Creating the mesh

We are going to use defaults for all operations here. The MEC STRUCT window, select

Mesh > Create > Solid > Start

Accept the default for the global minimum. The mesh is created and another dialog window opens (Element Quality Checks).


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This indicates some aspects of mesh quality that may be specified and then, by selecting the Check button at the bottom, evaluated for the

model. The results are indicated in columns on the right. If the mesh does not pass these quality checks, you may want to go back to

specify mesh controls (discussed below). Select Close. Here is an image of the default mesh, shown in wire frame.


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Improving the Mesh

In the mesh command, you can select the Controls option. This will allow you to select points, edges, and surfaces where you want to

specify mesh geometry such as hard points, maximum mesh size, and so on. Beware that excessively tight mesh controls can result in

meshes with many elements.

For example, setting a maximum mesh size along the curved ends of the slot results in the following mesh. Notice the better representation

of the curved edges than in the previous figure. This is at the expense of more than double the number of elements. Note that mesh

controls are also added to the model tree.


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Step 5. Creating the Output file

All necessary aspects of the model are now created (constraints, loads, materials, mesh). In the MEC STRUCT menu, select

Run


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This opens the Run FEM Analysis dialog window shown here. In the Solver pull-down list at the top, select ANSYS. In the Analysis list,

select Structural. You pick either Linear or Parabolic elements. The analysis we defined (containing constraints, loads, mesh, and

material) is listed. Select the Output to File radio button at the bottom and specify the output file name (default is the analysis name with

extension .ans). Select OK and read the message window.

We are now finished with Pro/E. Go to the top pull-down menus and select

Applications > Standard

Save the model file and leave the program.

Copy the .ans file from your Pro/E working directory to the directory you will use for running ANSYS.

Step 6. Importing into ANSYS

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File > Read Input From...

Select the .ans file you created previously. This will read in the entire model. You can display the model using (in the pull down menus)

Plot > Elements.

Step 7. Running the ANSYS solver

In the ANSYS Main Menu on the left, select

Solution > Solve > Current LS > OK

After a few seconds, you will be informed that the solution is complete.

Step 8. Viewing the results

There are myriad possibilities for viewing FEM results. A common one is the following:

General Postproc > Plot Results > Contour Plot > Nodal Solu

Pick the Von Mises stress values, and selectApply. You should now have a color fringe plot of the Von Mises stress displayed on the

model.

Updated: 8 November 2002 using Pro/ENGINEER 2001

RWT

Please report errors or omissions to Roger Toogood


U of A ANSYS Tutorials - Two Dimensional Truss

UofA ANSYS Tuto r ia lANSYS BASIC I NTERMEDI ATE ADVANCED POSTPROC. COMMAND PRINTABLE
mailto:[email protected]:[email protected]


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UofA ANSYS Tuto r ia lUT IL IT I ES TUTORIALS TUTORIALS TUTORIALS TUTORIALS LIN E FI LES VERSI ON

T wo D i m ens i ona l T r uss

Bicyc le Space Fram e

Plane St ress Bracket

Model ing Tools

Sol id Model ing

I n d e x


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Copyright 2001


Two Dimensional Truss

Introduction

This tutorial was created using ANSYS 7.0 to solve a simple 2D Truss problem. This is the first of four introductory ANSYS tutorials.

Problem Description

Determine the nodal deflections, reaction forces, and stress for the truss system shown below (E = 200GPa, A = 3250mm2).

(Modified from Chandrupatla & Belegunda, Introduction to Finite Elements in Engineering, p.123)

Preprocessing: Defining the Problem

1. Give the Simplified Version a Title (such as 'Bridge Truss Tutorial').

In the Utility menu bar select File > Change Title:

The following window will appear:

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Enter the title and click 'OK'. This title will appear in the bottom left corner of the 'Graphics' Window once you begin. Note: to get

the title to appear immediately, select Utility Menu > Plot > Replot

2. Enter Keypoints

The overall geometry is defined in ANSYS using keypoints which specify various principal coordinates to define the body. For this

example, these keypoints are the ends of each truss.

r We are going to define 7 keypoints for the simplified structure as given in the following table

keypointcoordinate

x y

1 0 0

2 1800 3118

3 3600 0

4 5400 3118

5 7200 0

6 9000 3118

7 10800 0

(these keypoints are depicted by numbers in the above figure)

r From the 'ANSYS Main Menu' select:Preprocessor > Modeling > Create > Keypoints > In Active CS




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The following window will then appear:

r To define the first keypoint which has the coordinates x = 0 and y = 0:

Enter keypoint number 1 in the appropriate box, and enter the x,y coordinates: 0, 0 in their appropriate boxes (as shown

above).

Click 'Apply' to accept what you have typed.

r Enter the remaining keypoints using the same method.

Note: When entering the final data point, click on 'OK' to indicate that you are finished entering keypoints. If you first press

'Apply' and then 'OK' for the final keypoint, you will have defined it twice!If you did press 'Apply' for the final point, simply press 'Cancel' to close this dialog box.



Units

N t th it f (i ) t ifi d It i th ibilit f th t th t i t t t f it


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Note the units of measure (ie mm) were not specified. It is the responsibility of the user to ensure that a consistent set of units are

used for the problem; thus making any conversions where necessary.

Correcting Mistakes

When defining keypoints, lines, areas, volumes, elements, constraints and loads you are bound to make mistakes. Fortunately these

are easily corrected so that you don't need to begin from scratch every time an error is made! Every 'Create' menu for generating

these various entities also has a corresponding 'Delete' menu for fixing things up.

3. Form Lines

The keypoints must now be connected

We will use the mouse to select the keypoints to form the lines.

r In the main menu select: Preprocessor > Modeling > Create > Lines > Lines > In Active Coord. The following window

will then appear:

r Use the mouse to pick keypoint #1 (i.e. click on it). It will now be marked by a small yellow box.

r Now move the mouse toward keypoint #2. A line will now show on the screen joining these two points. Left click and a



permanent line will appear.


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r Connect the remaining keypoints using the same method.

r When you're done, click on 'OK' in the 'Lines in Active Coord' window, minimize the 'Lines' menu and the 'Create' menu.

Your ANSYS Graphics window should look similar to the following figure.

Disappearing Lines

Please note that any lines you have created may 'disappear' throughout your analysis. However, they have most likely NOT been

deleted. If this occurs at any time from the Utility Menu select:

Plot > Lines

4. Define the Type of Element

It is now necessary to create elements. This is called 'meshing'. ANSYS first needs to know what kind of elements to use for our

problem:

r From the Preprocessor Menu, select: Element Type > Add/Edit/Delete. The following window will then appear:




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r Click on the 'Add...' button. The following window will appear:

r For this example, we will use the 2D spar element as selected in the above figure. Select the element shown and click 'OK'.

You should see 'Type 1 LINK1' in the 'Element Types' window.

r Click on 'Close' in the 'Element Types' dialog box.

5. Define Geometric Properties

We now need to specify geometric properties for our elements:

r In the Preprocessor menu, select Real Constants > Add/Edit/Delete




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r ClickAdd... and select 'Type 1 LINK1' (actually it is already selected). Click on 'OK'. The following window will appear:

r As shown in the window above, enter the cross-sectional area (3250mm):

r Click on 'OK'.

r 'Set 1' now appears in the dialog box. Click on 'Close' in the 'Real Constants' window.

6. Element Material Properties

You then need to specify material properties:



r In the 'Preprocessor' menu select Material Props > Material Models


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r In the Preprocessor menu select Material Props > Material Models

r Double click on Structural > Linear > Elastic > Isotropic

We are going to give the properties of Steel. Enter the following field:

EX 200000

r Set these properties and click on 'OK'. Note: You may obtain the note 'PRXY will be set to 0.0'. This is poisson's ratio and is



not required for this element type. Click 'OK' on the window to continue. Close the "Define Material Model Behavior" by

clicking on the 'X' box in the upper right hand corner


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clicking on the X box in the upper right hand corner.

7. Mesh Size

The last step before meshing is to tell ANSYS what size the elements should be. There are a variety of ways to do this but we will

just deal with one method for now.

r In the Preprocessor menu select Meshing > Size Cntrls > ManualSize > Lines > All Lines

r In the size 'NDIV' field, enter the desired number of divisions per line. For this example we want only 1 division per line,

therefore, enter '1' and then click 'OK'. Note that we have not yet meshed the geometry, we have simply defined the element

sizes.

8. Mesh

Now the frame can be meshed.

r In the 'Preprocessor' menu select Meshing > Mesh > Lines and click 'Pick All' in the 'Mesh Lines' Window

Your model should now appear as shown in the following window




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Plot Numbering

To show the line numbers, keypoint numbers, node numbers...

q From the Utility Menu (top of screen) select PlotCtrls > Numbering...

q Fill in the Window as shown below and click 'OK'




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Now you can turn numbering on or off at your discretion

Saving Your Work

Save the model at this time, so if you make some mistakes later on, you will at least be able to come back to this point. To do this, on the

Utility Menu select File > Save as.... Select the name and location where you want to save your file.

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

system crash or what have you.

Solution Phase: Assigning Loads and Solving

You have now defined your model. It is now time to apply the load(s) and constraint(s) and solve the the resulting system of equations.

Open up the 'Solution' menu (from the same 'ANSYS Main Menu').

1. Define Analysis Type

First you must tell ANSYS how you want it to solve this problem:



r From the Solution Menu, select Analysis Type > New Analysis.


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r Ensure that 'Static' is selected; i.e. you are going to do a static analysis on the truss as opposed to a dynamic analysis, for

example.

r Click 'OK'.

2. Apply Constraints

It is necessary to apply constraints to the model otherwise the model is not tied down or groundedand a singular solution will

result. In mechanical structures, these constraints will typically be fixed, pinned and roller-type connections. As shown above, the

left end of the truss bridge is pinned while the right end has a roller connection.

r In the Solution menu, select Define Loads > Apply > Structural > Displacement > On Keypoints




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r Select the left end of the bridge (Keypoint 1) by clicking on it in the Graphics Window and click on 'OK' in the 'Apply U,ROT on KPs' window.

r This location is fixed which means that all translational and rotational degrees of freedom (DOFs) are constrained.

Therefore, select 'All DOF' by clicking on it and enter '0' in the Value field and click 'OK'.

You will see some blue triangles in the graphics window indicating the displacement contraints.



r Using the same method, apply the roller connection to the right end (UY constrained). Note that more than one DOF

t i t b l t d t ti i th "A l U ROT KP " i d Th f d t 'd l t' th 'All


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constraint can be selected at a time in the "Apply U,ROT on KPs" window. Therefore, you may need to 'deselect' the 'All

DOF' option to select just the 'UY' option.

3. Apply Loads

As shown in the diagram, there are four downward loads of 280kN, 210kN, 280kN, and 360kN at keypoints 1, 3, 5, and 7

respectively.

r Select Define Loads > Apply > Structural > Force/Moment > on Keypoints.

r Select the first Keypoint (left end of the truss) and click 'OK' in the 'Apply F/M on KPs' window.

r Select FY in the 'Direction of force/mom'. This indicate that we will be applying the load in the 'y' direction

r Enter a value of -280000 in the 'Force/moment value' box and click 'OK'. Note that we are using units of N here, this is

consistent with the previous values input.

r The force will appear in the graphics window as a red arrow.

r Apply the remaining loads in the same manner.

The applied loads and constraints should now appear as shown below.




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4. Solving the System

We now tell ANSYS to find the solution:

r In the 'Solution' menu select Solve > Current LS. This indicates that we desire the solution under the current Load Step

(LS).




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r The above windows will appear. Ensure that your solution options are the same as shown above and click 'OK'.

r Once the solution is done the following window will pop up. Click 'Close' and close the /STATUS Command Window..

Postprocessing: Viewing the Results

1. Hand Calculations

We will first calculate the forces and stress in element 1 (as labeled in the problem description).




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2. Results Using ANSYS

Reaction Forces

A list of the resulting reaction forces can be obtained for this element

r from the Main Menu select General Postproc > List Results > Reaction Solu.

r Select 'All struc forc F' as shown above and click 'OK'




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These values agree with the reaction forces claculated by hand above.

Deformation

r In the General Postproc menu, select Plot Results > Deformed Shape. The following window will appear.

r Select 'Def + undef edge' and click 'OK' to view both the deformed and the undeformed object.




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r Observe the value of the maximum deflection in the upper left hand corner (DMX=7.409). One should also observe that the

constrained degrees of freedom appear to have a deflection of 0 (as expected!)

Deflection

For a more detailed version of the deflection of the beam,

r From the 'General Postproc' menu select Plot results > Contour Plot > Nodal Solution. The following window will

appear.




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r Select 'DOF solution' and 'USUM' as shown in the above window. Leave the other selections as the default values. Click

'OK'.




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r Looking at the scale, you may want to use more useful intervals. From the Utility Menu select Plot Controls > Style >

Contours > Uniform Contours...

r Fill in the following window as shown and click 'OK'.




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You should obtain the following.




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r The deflection can also be obtained as a list as shown below. General Postproc > List Results > Nodal Solution select

'DOF Solution' and 'ALL DOFs' from the lists in the 'List Nodal Solution' window and click 'OK'. This means that we want

to see a listing of all degrees of freedom from the solution.



r Are these results what you expected? Note that all the degrees of freedom were constrained to zero at node 1, while UY was

constrained to zero at node 7.


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r If you wanted to save these results to a file, select 'File' within the results window (at the upper left-hand corner of this list

window) and select 'Save as'.

Axial Stress

For line elements (ie links, beams, spars, and pipes) you will often need to use the Element Table to gain access to derived data (ie

stresses, strains). For this example we should obtain axial stress to compare with the hand calculations. The Element Table is

different for each element, therefore, we need to look at the help file for LINK1 (Type help link1 into the Input Line). From

Table 1.2 in the Help file, we can see that SAXL can be obtained through the ETABLE, using the item 'LS,1'

r From the General Postprocessor menu select Element Table > Define Table

r Click on 'Add...'

r As shown above, enter 'SAXL' in the 'Lab' box. This specifies the name of the item you are defining. Next, in the 'Item,

Comp' boxes, select 'By sequence number' and 'LS,'. Then enter 1 after LS, in the selection box

r Click on 'OK' and close the 'Element Table Data' window.

r Plot the Stresses by selecting Element Table > Plot Elem Table

r The following window will appear. Ensure that 'SAXL' is selected and click 'OK'




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r Because you changed the contour intervals for the Displacement plot to "User Specified" - you need to switch this back to

"Auto calculated" to obtain new values for VMIN/VMAX.Utility Menu > PlotCtrls > Style > Contours > Uniform Contours ...

Again, you may wish to select more appropriate intervals for the contour plot

r List the Stresses

s From the 'Element Table' menu, select 'List Elem Table'

s From the 'List Element Table Data' window which appears ensure 'SAXL' is highlighted

s Click 'OK'




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Note that the axial stress in Element 1 is 82.9MPa as predicted analytically.

Command File Mode of Solution

The above example was solved using a mixture of the Graphical User Interface (or GUI) and the command language interface of ANSYS.

This problem has also been solved using the ANSYS command language interface that you may want to browse. Open the .HTML

version, copy and paste the code into Notepad or a similar text editor and save it to your computer. Now go to 'File > Read input from...'

and select the file. A .PDF version is also available for printing.

Quitting ANSYS

To quit ANSYS, select 'QUIT' from the ANSYS Toolbar or select Utility Menu/File/Exit.... In the dialog box that appears, click on 'Save

Everything' (assuming that you want to) and then click on 'OK'.


U of A ANSYS Tutorials - Bicycle Space Frame

UofA ANSYS Tu to r ia lANSYS

U T I L I T I ESBASI C

TUTORI ALSI NTERMEDI ATE


POSTPROC.TUTORIALS

COMMANDLINE FI LES

PRINTABLEVERSI ON


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T w o D im e n s io n al T ru ss

Bicyc le Space Frame

Plane St ress Bracke t

Mode l ing Too ls

So l id Mode l ing

I n d e x


C o mme n t s

MecE 563


U n ive rs i t y o f A lb e r t a

ANSYS I nc.

Copyright 2001University of Alberta

Space Frame Example

| Ver i f i cat ion Examp le | | Preprocessing | | Solut ion | | Postprocessing | | Com m and Line |

| Bicycle Example | | Preprocessing | | Solut ion | | Postprocessing | | Com m and Line |

Introduction

This tutorial was created using ANSYS 7.0 to solve a simple 3D space frame problem.

Problem Description

The problem to be solved in this example is the analysis of a bicycle frame. The problem to be modeled in this example is a simple bicycleframe shown in the following figure. The frame is to be built of hollow aluminum tubing having an outside diameter of 25mm and a wall

thickness of 2mm.

Verification

The first step is to simplify the problem. Whenever you are trying out a new analysis type, you need something (ie analytical solution orexperimental data) to compare the results to. This way you can be sure that you've gotten the correct analysis type, units, scale factors, etc.

http://www.mece.ualberta.ca/tutorials/ansys/BT/Bike/Bike.html (1 of 29)03/09/2005 19:40:50


The simplified version that will be used for this problem is that of a cantilever beam shown in the following figure:
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Preprocessing: Defining the Problem

1. Give the Simplified Version a Title (such as 'Verification Model').

Utility Menu > File > Change Title

2. Enter Keypoints

For this simple example, these keypoints are the ends of the beam.

r We are going to define 2 keypoints for the simplified structure as given in the following table

keypointcoordinate

x y z

1 0 0 0

2 500 0 0

r From the 'ANSYS Main Menu' select:Preprocessor > Modeling > Create > Keypoints > In Active CS

3. Form Lines

The two keypoints must now be connected to form a bar using a straight line.



r Select: Preprocessor > Modeling> Create > Lines > Lines > Straight Line.

Pi k k i t #1 (i li k it) It ill b k d b ll ll b


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r Pick keypoint #1 (i.e. click on it). It will now be marked by a small yellow box.

r Now pick keypoint #2. A permanent line will appear.

r When you're done, click on 'OK' in the 'Create Straight Line' window.

4. Define the Type of Element

It is now necessary to create elements on this line.

r From the Preprocessor Menu, select: Element Type > Add/Edit/Delete.

r Click on the 'Add...' button. The following window will appear:

r For this example, we will use the 3D elastic straight pipe element as selected in the above figure. Select the element shown andclick 'OK'. You should see 'Type 1 PIPE16' in the 'Element Types' window.

r Click on the 'Options...' button in the 'Element Types' dialog box. The following window will appear:




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r Click and hold the K6 button (second from the bottom), and select 'Include Output' and click 'OK'. This gives us extra force andmoment output.

r Click on 'Close' in the 'Element Types' dialog box and close the 'Element Type' menu.

5. Define Geometric Properties

We now need to specify geometric properties for our elements:

r In the Preprocessor menu, select Real Constants > Add/Edit/Delete

r ClickAdd... and select 'Type 1 PIPE16' (actually it is already selected). Click on 'OK'.

r Enter the following geometric properties:

Outside diameter OD: 25

Wall thickness TKWALL: 2

This defines an outside pipe diameter of 25mm and a wall thickness of 2mm.

r Click on 'OK'.



r 'Set 1' now appears in the dialog box. Click on 'Close' in the 'Real Constants' window.

6. Element Material Properties


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p

You then need to specify material properties:

r In the 'Preprocessor' menu select Material Props > Material Models...

r Double clickStructural > Linear > Elastic and select 'Isotropic' (double click on it)

r Close the 'Define Material Model Behavior' Window.

We are going to give the properties of Aluminum. Enter the following field:

EX 70000

PRXY 0.33

r Set these properties and click on 'OK'.

7. Mesh Size

r In the Preprocessor menu select Meshing > Size Cntrls > ManualSize > Lines > All Lines

r In the size 'SIZE' field, enter the desired element length. For this example we want an element length of 2cm, therefore, enter'20' (i.e 20mm) and then click 'OK'. Note that we have not yet meshed the geometry, we have simply defined the element sizes.

(Alternatively, we could enter the number of divisions we want in the line. For an element length of 2cm, we would enter 25 [ie25 divisions]).

NOTE

It is not necessary to mesh beam elements to obtain the correct solution. However, meshing is done in this case so that we can obtainresults (ie stress, displacement) at intermediate positions on the beam.

8. Mesh

Now the frame can be meshed.

r In the 'Preprocessor' menu select Meshing > Mesh > Lines and click 'Pick All' in the 'Mesh Lines' Window

9. Saving Your Work

Utility Menu > File > Save as.... Select the name and location where you want to save your file.

Solution Phase: Assigning Loads and Solving



1. Define Analysis Type

r From the Solution Menu, select 'Analysis Type > New Analysis'.


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r From the Solution Menu, select Analysis Type > New Analysis .

r Ensure that 'Static' is selected and click 'OK'.

2. Apply Constraints

r In the Solution menu, select Define Loads > Apply > Structural > Displacement > On Keypoints

r Select the left end of the rod (Keypoint 1) by clicking on it in the Graphics Window and click on 'OK' in the 'Apply U,ROT on

KPs' window.

r This location is fixed which means that all translational and rotational degrees of freedom (DOFs) are constrained. Therefore,select 'All DOF' by clicking on it and enter '0' in the Value field and click 'OK'.

3. Apply Loads

As shown in the diagram, there is a vertically downward load of 100N at the end of the bar

r In the Structural menu, select Force/Moment > on Keypoints.

r Select the second Keypoint (right end of bar) and click 'OK' in the 'Apply F/M' window.

r Click on the 'Direction of force/mom' at the top and select FY.

r Enter a value of -100 in the 'Force/moment value' box and click 'OK'.

r The force will appear in the graphics window as a red arrow.

The applied loads and constraints should now appear as shown below.




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4. Solving the System

We now tell ANSYS to find the solution:

r Solution > Solve > Current LS

Postprocessing: Viewing the Results

1. Hand Calculations

Now, since the purpose of this exercise was to verify the results - we need to calculate what we should find.

Deflection:

The maximum deflection occurs at the end of the rod and was found to be 6.2mm as shown above.

Stress:




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The maximum stress occurs at the base of the rod and was found to be 64.9MPa as shown above (pure bending stress).

2. Results Using ANSYS

Deformation

r from the Main Menu select General Postproc from the 'ANSYS Main Menu'. In this menu you will find a variety of options,

the two which we will deal with now are 'Plot Results' and 'List Results'

r Select Plot Results

Documents

Tutorial ANSYS Universidad de Alberta