ANSYS Quick Start

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TIPSGetting Started With ANSYS:Introduction:

www.ansys.belcan.com

by Paul Dufour

ANSYS is a sophisticated and comprehensive finite element program that has capabilities in many different physics fields such as static structural, nonlinear, thermal, implicit and explicit dynamics, fluid flow, electromagnetics, and electric field analysis. It can also perform coupled field analysis combining one or more of these different physics. Obviously because ANSYS is such a huge program with so many capabilities (even within just one of these physics fields) it is impossible to cover everything in this short guide. This document will give an introduction as to how the ANSYS program works and how these basic skills will be applicable to any type of analysis within ANSYS. The most important concepts in using ANSYS will be addressed here in a compressed format. The key to becoming productive in any computer aided engineering program is to start to think like the program thinks, to get the big picture of how it works in general. That is the primary goal of this guideline. A Couple of Preliminaries: ANSYS is an integrated program with all operations performed under one GUI. Creating the model, running it, and postprocessing the results are all done without leaving the ANSYS environment. There are several different ways of working within ANSYS. This stems from the fact that like every program, ANSYS is driven by commands. The difference between ANSYS and say, Microsoft Word, is that when you click on an icon in Word, you have no idea what command was executed behind the scenes to make the program do what you asked. ANSYS gives you easy access to these commands if you want to use them. These commands are simple to use; just a keyword followed by several arguments. By stacking these commands together in a text file the power to automate and script ANSYS is one key reason why I think it is superior to other FEA codes on the market. More on this powerful scripting capability in a later section. New ANSYS users generally dont care much about scripting to start with and just want to figure out how to do what they want within the GUI environment, and thats where we will start as well. Each key concept will be explained as succinctly as possible, then at the end we will do a simple problem using several different approaches to put it all together. Starting ANSYS: When you start ANSYS from the Windows Start Menu you get three basic choices. ANSYS Workbench: This is a brand new GUI with an emphasis on CAD connectivity, ease of use, and easy management of assembly contact. This GUI is covered in a separate guideline.

Copyright 2003 Belcan Engineering Group, Inc.

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ANSYS: This starts ANSYS in the traditional GUI. The program starts immediately using the settings last changed under the next item, Configure ANSYS Products. This guideline will cover this GUI. Configure ANSYS Products: This sounds like something you might use only the first time you fire up ANSYS, but surprise! Typically this is where you will start the program from every time. This choice brings up what has been always called the ANSYS Launcher.

Pick your environment: ANSYS or Workbench, or batch mode. Any license you have paid for shows up here.

Start your ANSYS session with the specified parameters.

File Management Tab: All files created in this session will be called jobname.something, and be created in the working directory specified here. The default jobname is file. I like to organize my work by different directories and always use the jobname file, but this is a personal preference. Key ANSYS files you need to know about:jobname.db This is your database, where your model is stored. jobname.dbb When you save, your existing database file is copied to this before actually saving as a

backup.jobname.log Everything you do in a session is written to this file in the form of commands. jobname.rxx Results file. xx = st for structural, xx = th for thermal, etc.

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Preferences Tab: The 3D graphics driver allows you to rotate a shaded view of your model. Most newer graphics cards can handle this fine. Under the Profiles pull down menu you can save settings and easily recall them to quickly start ANSYS with specific settings that you have defined previously. The Help System: ANSYS has excellent documentation available under the help menu in the main GUI window. The amount and comprehensiveness of information available under the help menu is both a blessing and a curse. What you want to know is there, but at times its hard to dig out due to the sheer amount of information. A couple of hints: Use the tutorials found under Help ANSYS Tutorials. There are nine different tutorials here that are step by step, mouse click by mouse click instructions for various types of analysis. Under the Analysis Guide for each discipline, there are also step by step instructions with explanations on how to do each type of simulation. These are well donetake advantage of them!

Under the Index tab start typing and it will jump to that section of the list of topics as shown at left.

When searching, use more than one word to narrow down the search. To search on a specific phrase put the words in double quotes.

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The ANSYS GUI:Utility menu. These are ancillary functions that are not directly related to creating, solving and selecting results to look at for your finite element model. Raise hidden. If a dialog disappears behind the main window, bring it back with this.

Can type in ANSYS commands here if you know them. Customize this toolbar with frequently used commands or create push button automation with macros assigned to a button. The Main Menu. Nodes of the tree expand and contract. If you collapse a full branch, it remembers where you were upon reopening, so you dont have to re-drill down to get to that item.

Graphics window. This is where you plot things to the screen.

Manipulate your model view with these buttons.

Look at this! ANSYS will prompt you for what to do next.

This GUI is fairly easy to use, however there is some ANSYS-speak related to basic operation: Resume: This is opening a previously saved database. It is important to know that if you simply resume a database, it doesnt change the jobname. For example: You start ANSYS with a jobname of file. Then you resume mymodel.db, do some work, then save. That save is done to file.db! Avoid this issue by always resuming using the icon on the toolbar. If you open mymodel.db using this method, it resumes the model and automatically changes the jobname to mymodel. Plotting: Contrary to the name, this has nothing to do with sending an image to a plotter or printer. Plotting in ANSYS refers to drawing something in the graphics window. Generally you plot one type of entity (lines, elements, etc.) to the screen at a time. If you want to plot more than one kind of entity use, Plot Multiplot, which by default will plot everything in your model at once. Plot Controls: This refers to how you want your plot to look on the screen (shaded, wireframe, entity numbers on or off, etc). Other plot control functions include sending an image to a graphics file or printer.

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Mouse Functionality: Pressing the scroll wheel button is the same as a middle mouse button. Picking Entities: Left Button: Picks an entity. Picking is cumulative, so you dont need to press control or shift to pick more than one entity. Click and hold the button, then move the cursor around until the entity you want is highlighted. When you release the button the highlighted entity is selected. Middle Button: Completes a selection. This is like clicking Apply in the picking dialog (also called the picker). Right Button: Toggle back and forth between pick and unpick you know what mode you in. mode. Cursor changes so

Manipulating the Model View: (you can change these defaults to different buttons if desired) CTRL + Left Button: Pan the model side to side and up and down. CTRL + Middle Button: Move the mouse left and right to rotate about screen Z. Up and down zooms in and out. CTRL + Right Button: Rotate the model. Right Button: Click and drag the right button to zoom in using a window. Rolling the scroll wheel also zooms in and out. Right Button Pop-up Menu: When you click the right button in the graphics area you get this pop-up with some very common graphics functions. ANSYS does not always refresh the graphics screen so Replot is very handy. Fit makes your whole model visible. Zoom Back will go back to the view the way it was just before you zoomed in. Importing or Creating Geometry: Import CAD geometry using File Import. ANSYS comes with IGES support by default but there are Geometry Interfaces available for Pro/E, CATIA, UG, Solidworks, Parasolid, etc. IGES is the oldest of these formats and does not work very well for solids, but is OK for wireframe geometry. All of these geometry interfaces on the ANSYS Traditional side perform a translation of the geometry into an ANSYS Neutral File (.anf) format, which it then reads in. In Workbench there is no translation, it works with the native CAD format geometry.

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Geometry in ANSYS is created from Main Menu Preprocessor Modeling Create and has the following terminology, KEYPOINTS: These are points, locations in 3D space. LINES: This includes straight lines, curves, circles, spline curves, etc. Lines are typically defined using existing keypoints. AREAS: This is a surface. When you create an area, its associated lines and keypoints are automatically created to border it. VOLUMES: This is a solid. When you create a