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Ansys User Guide

University of Sheffield

Department of Mechanical Engineering


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ANSYS USER GUIDE ....................................................... 1

ANSYS USER INTERFACE.................................................................................................. 3

ANSYS MENU STRUCTURE............................................................................................... 7

ANSYS FILE TYPES............................................................................................................ 12

ENTITY SELECTION METHODS.................................................................................... 15

ANSYS MODEL VIEWING AND HARDCOPY............................................................... 18

MODELLING IN ANSYS.................................................................................................... 21


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Ansys User Interface

Ansys is a good pre-processing, solution and post-processing tool for finite element

modelling. The Ansys program is organised into two levels. The initial entry level is

the BEGIN level. From this level you can access the desired processors as shownbelow.

The Ansys graphical user interface (GUI) is split into four main areas. the graphics

area, the utility menu, the main menu and the Ansys toolbar.

Highlighted in the figure below is the standard layout of the GUI. The different

windows that make-up the GUI can be moved around the screen at the users

discretion.

The Graphics Area

The Graphics area is the window in which the entities are displayed. The window can

be split into smaller windows. Within these windows entities can be animated,

rotated, selected, deleted and so on.

BEGIN LEVEL

Processor Level

PREP7 SOLU POST1 POST26 OTHER

Enter Ansys Exit Ansys


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The Utility Menu

The Utility menu is the light blue menu shown below

This menu contains controls for opening and saving files, selecting entities, producing

plots etc. By clicking on any of the 10 options pop-up menus under each option

appear.

The ten options are:

File File opening, clearing a database, saving, importing and

exporting files

Select Selecting entities and components

List Lists entities and components

Plot Plots entities and components, multiple plots, array parameters

and material data

PlotControls Hardcopy, component numbering, annotation, animation and

plot style

WorkPlane Working plane creation and manipulation, coordinate systemcreation and manipulation

Parameters Array parameters, scaler parameters and parameter edit


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Macros Macro creation for data manipulation

MenuCtrls Controls the format of the GUI

Help Online help and documentation

The Ansys Input

This window shows program prompt messages and allows you to type in commands.

All previously typed commands also appear in this window.

The Ansys Toolbar

The Ansys toolbar menu has options for saving and resuming models, powergraphicsand web-interfacing.

The Main Menu

The main menu consists of nine options. Each menu topic brings up a submenu

(indicated by a > after the topic) or performs an action. The symbol on the right-hand

of the topic indicates the action.


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These are.

Preferences This sets model preferences, such as thermal, structural or

modal analysis

Preprocessor Enters the preprocessing sub-menu

Solution Enters the solution sub-menu

General Postproc Enters the general postprocessor

TimeHist Postproc Enters the time history postprocessor

Design Opt Enters the Design Optimisation routines

Radiation Matrix Sets options for radiation thermal analysis

Run-Time Stats Gives run-time statistics


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Ansys Menu Structure

From each of the menu bars, further menus appear. These menus can lead to further

pop-up menus, sub-menus, data entry fields and toggles.

All menus are similar to the main menu in colour and in operation. Each menu acts

like a tree to further menus all of which stay displayed until unselected.

Sub-menus

From the main menu a sub-menu will look like the one shown below.

The preprocessor menu is extremely important. Most of the work in creating a

model is done from this menu.

From the utility menu a sub-menu will look like the one shown below.


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Pop-up Menu

A pop-up menu will typically look like the one shown below. Note that the menu is

split into several areas.

At the top of the menu is the pickorun-pickoption. With this we can either select or

un-select entities using the mouse buttons. The next field tells us the location of the

item and number of items we are picking. Below this area is the data entry area. At

the bottom of the pop-up menu is a set of buttons for applying the required command.These buttons are common to Ansys pop-up windows and function as follows:


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OK This applies the command and closes the window

Apply This applies the command and leaves the window open

Reset Resets the picked or un-picked options

Cancel Cancels the command and closes the window

Help Produces online help

Data Entry Field

A data entry field will typically look like the one shown below.

Data such as Youngs Modulus and Poissons ratio can be entered using the keyboardin the required field.

Toggle


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Toggle boxes allow certain options to be set without actually typing anything. They

are typically used when Ansys want the user to choose between one option andanother.

In the toggle box shown above we are choosing to import a CAD file using the default

option and also choosing to combine (merge) coincident keypoints thus enabling us to

create a areas and volumes.

Exiting Ansys

We can leave Ansys by clicking on file from the utility menu and then exit at the

bottom of the following menu.

This action brings up the following toggle menu.


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This menu gives the user four options for saving and exiting the model.


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Ansys File Types

As can be expected with a powerful Finite Element tool such as Ansys various

different files are created during the different phases of model creation.

Most files can be created from the file sub-menu from under the utility menu.

Importing Files

Files can be imported from different CAD programs. Using the File option from the

utility menu.

Brings up the sub-menu.

By clicking on Import a further sub-menu gives us our file options. Typically this

might be an IGES file. Finally a toggle-box will appear offering several options.


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In version 5.4 of Ansys (our current version) objects imported by the Default option

cannot be altered. If further work is required to the object then the Alternate option isnecessary. Ansys will try and create volumes and areas from the lines imported from

the CAD geometry.

Saving Files

You can save files in Ansys using the Filesub-menu as described earlier. The file willautomatically save as file.db (the default jobname). This is known as the database. A

back-up of your database has the file extension dbb. The original database is always

copied to a dbb file when a save command is executed.

To read a database into Ansys use the resume command from File

sub-menu.

Exporting Files

IGES files can be exported from the File sub-menu using the export option.

Solution Files

During an analysis Ansys creates various files for storing data. These are.

File.emat element matrix file on previous iteration

File.esav element matrix file on most recent iteration

File.tri triangularised matrix files

File.err file listing all error messages generated during modelling

File.log log file of all commands issued

File.page scratch file for virtual space

The esav, emat and tri files are automatically deleted after leaving Ansys once a jobhas been solved. This feature is unique to Sheffield University. There are several


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other files created for different applications, which will not be dealt with in these

notes.

Results Files

For a standard structuralanalysis the results file has the extension .rst. Hence adefault result file is file.rst

All Ansys files can be copied renamed and saved in the appropriate operating system.


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Entity Selection Methods

Ansys has an extremely powerful select logic. This select logic is available from the

File utility menu underselect. It is tremendously useful to understand how this works.

The select sub-menu is shown below.

Entities that you can select are nodes, elements, keypointslines, areas and volumes.

The default option is nodes.

The sub-menu is divided into three areas. The top portion allows us to toggle onto

which entities that we wish to select. The second toggle box in this portion allows us

to choose how we would like to select the entities. There are many different ways in

which we can do this. Several examples are shown in the following sub-menus.


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Using this sub-menu we can select lines by their global position in the current co-

ordinate system. A very useful technique is to be able to select things attached to

entities we have already selected. So for instance we can select lines attached to areas,

keypoints attached lines and so on. In the sub-menu shown we are selecting areas

attached to the lines that we have already selected.


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The second portion of the sub-menu offers four options on what we select our entities

from. These four are.

From Full select entities from all entities that exist

Reselect select entities from those already selected

Also Sele add to the entities already selected

Unselect unselect entities already selected

Also in this portion of the sub-menu are buttons so that we can select everything,

invert our current selection and select none of the entities chosen.

The bottom portion of the panel is our standard Ansys area for executing our desired

commands.


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Ansys Model Viewing and Hardcopy

The ANSYS program allows you to pan, zoom and rotate your model. There is a

special sub-menu from the utility menu for doing this underPlot Controls.

Note that this sub-menu has options for various graphics options. Through this menu

we can change the style of our graphics plot, the colours used, the number of windowsand so on. From this window we are also able to produce hardcopy. Clicking on

hardcopy will bring up the following sub-menu. By choosing graphics window only,

color and print file, the graphics window output will be printed on a colour print.

You must make sure that the print option is set to lpr Pstgcolps for the output to be

produced at StGeorges IT centre. Note that the file is automatically saved as an

encapsulated postscript file. Note that only postscript can be printed directly to the

StGeorges printers.


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After clicking on pan, zoom rotate the following sub-menu appears.

This menu is extremely useful for manipulating the model within the graphicswindow. The top portion of the menu contains button for selecting standard user


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views such as isometric or oblique. Below these standard view are options for

zooming in or out of portions of the model. The next portion of the menu translates

orrotates the model. The bottom portion of the menu allows dynamic manipulation

of the model.


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Modelling in Ansys

There are five main phases of the Ansys modelling process.

Geometry creation and editing

Element creation and editing

Load and boundary condition application

Solving of analysis

Results scrutiny and post-processing.

The main menu bar allows access to the functionality needed for these tasks.

Introduction to some sub-menus

The pre-processor sub-menu is shown below. From only a small number of sub-

menus below this, a model can be created, meshed and loaded.


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Element Type this sets the element type that we are going to use

during our analysis.

Real Constant real constants are element dependant properties.

Material Properties this sets the material properties such as Youngs

Modulus and Poissons ratio

You must always choose an element type and material property before attempting to run any

analysis in Ansys.

Note that the pre-processing menu is split into several sections, modelling, attributesmeshtool and so

on. The modelling section allows us to create the required geometry the first phase of our modelling

process.

Using the create sub-menu we can produced our geometry from pre-defined shapes

called primitives. These shapes can be circles, rectangles, blocks and several other

shapes outlined in the menu.


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The create rectangle sub-menu offers several options for producing a rectangle and is

shown below.

If we use the by-dimensions option then the following data entry box appears.

We can put the dimensions of the rectangle we desire into the boxes and a rectangle

will appear in the graphics area.


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In Ansys surfaces (areas) are made up of lines. Lines are connected together by

keypoints. A plot of the lines forming a rectangle is shown in the following figure.

We can similarly create three-dimensional shapes using the same process. In Ansys

these three-dimensional shapes are known as volumes.

A volume is shown below.


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A volume is made from a set ofareas.

Meshing

The second phase of our modelling process is the element creation. From the pre-

processor menu we can see that one of the sub-sections is labelled Meshing. By

clicking on mesh, the following sub-menu appears.

This menu allows us to free ormap mesh areas or volumes. Free meshing means the

surface will be meshed with quadrilateral and triangular elements. Mapped

meshing means the surface will be only meshed with quadrilateral elements. Only

certain geometrys can be map meshed.


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Within the Meshing area of the pre-processor menu are options for element size

control and other meshing functions. In Ansys all these option are combined in a sub-

menu called the Meshtool. This menu is shown below.

From this menu element size can be set, the mesh can be refined and so on.

Loading and boundary conditions

We can apply loads and constraints (and delete them) either from the preprocessor or

the solution processor sub-menus.


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If we click on apply the following sub-menu appears.


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If we choose Force/moment the following sub-menu appears.

We can apply forces on nodes or keypoints. Choosing nodes our standard pop-up

menu appears. After picking the nodes on which we want to apply the force, the

following data entry box appears.


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By toggling on the Direction of force/mom button we can choose the loading

direction of the force.

We will then be prompted with our standard pop-up menu. The force will be

represented as a red arrow.

Similarly by clicking on apply then Displacement from the solution processor

window then following sub-menu appears.

By clicking on nodes our standard pop-menu will appear


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After picking the nodes we wish to constrain the following data entry box appears.

Highlighting ALL DOF and making the value of the displacement zero fully

constrains the selected nodes.

Blue arrows represent tranlational degrees of freedom and brown arrows rotational

degrees of freedom.

Solving of analysis

We enter the solution processor from the main menu as shown below.


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We can also apply loads and constraints from the solution processor. To solve an

analysis we click on solve current ls.

Results scrutiny and postprocessing

After clicking on the main menu General Postprocessor the following sub-menu

appears.


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If we then click on Nodal solution the following sub-menu appears. Note that we are

able to select our desired output firstly by highlighting the item (stress, strain etc)and

then the component (sx, sy etc).


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Once we have decided on our output by clicking OK (or apply depending on

preference) we should get output as shown below.

The default stress output is for the mid surface of the shell element. To select the top

orbottom surface, type top orbottom in the input menu before plotting the stress.

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