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ÿþTIPS www.ansys.belcan.com Getting Started With ANSYS: by Paul Dufour Introduction: 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 don t care much about scripting to start with and just want to figure out how to do what they want within the GUI environment, and that s 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. 1 © Copyright 2003 Belcan Engineering Group, Inc. 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. 2 © Copyright 2003 Belcan Engineering Group, Inc. 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 it s 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 done& take 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. 3 © Copyright 2003 Belcan Engineering Group, Inc. The ANSYS GUI: Utility menu. These are ancillary functions that are not directly related to creating, solving and selecting results to Raise hidden. If a look at for your finite element model. 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 Graphics window. This is full branch, it remembers where you  plot things to the where you were upon screen. reopening, so you don t have to re-drill down to get to that item. 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 doesn t 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. 4 © Copyright 2003 Belcan Engineering Group, Inc. 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 don t 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 mode. Cursor changes so you know what mode you in. 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. 5 © Copyright 2003 Belcan Engineering Group, Inc. 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, it s associated lines and keypoints are automatically created to border it. VOLUMES: This is a solid. When you create a volume, it s associated areas, lines and keypoints are automatically created. SOLID MODEL: In most packages this would refer to the volumes only, but in ANSYS this refers to your geometry. Any geometry. A line is considered a  solid model . You can t delete a child entity without deleting its parent, in other words you can t delete a line if it s part of an area, can t delete a keypoint if it s the end point of a line, etc. Boolean Operations: Top Down style modeling can be a very convenient way to work. Instead of first creating keypoints, then lines from those keypoints, then areas from the lines and so on (bottom up modeling), start with volumes of basic shapes and use Boolean operations to add them, subtract them, divide them etc. Even if you are creating a shell model, for example a box, you could create the box as a volume (a single command) and then delete the volume keeping the existing areas, lines and keypoints. These kinds of operations are found under  Main Menu ’! Preprocessor ’! Modeling ’! Operate ’! Booleans with some common ones being: Add: Take two entities that overlap (or are at least touching) and make them one. Subtract: Subtract one entity from another. To make a hole in a plate, create the plate (area of volume) then create a circular area or cylinder and subtract it from the plate. Glue: Take two entities that are touching and make them contiguous or congruent so that when meshed they will share common nodes. For example, using default mesh parameters, L7 L7 Area 2 L8 L6 L8 L6 L5 L5 L3 L3 Meshing without gluing areas. L2 Area 1 L2 L4 L4 L1 L1 Meshing after gluing areas. L7 L8 Area 2 L10 Note: The coincident nodes on the common line L9 L11 between the two areas will be automatically merged. L4 Area 1 L2 You don t have to manually equivalence them like in some other codes. L1 6 © Copyright 2003 Belcan Engineering Group, Inc. The Working Plane: All geometry is created with respect to the working plane, which by default is aligned with the global Cartesian coordinate system. The  Working Plane is actually the XY plane of the working coordinate system. The working coordinate system ID is coordinate system 4 in ANSYS. Global Cartesian is ID 0, Global Cylindrical is ID 1, and Global Spherical is ID 2. Working Plane Hints: Turn on the working plane so you can see it with,  Utility Menu ’! Work Plane ’! Display Working Plane . Change the way the working plane looks or adjust the snap settings under  Utility Menu ’! Work Plane ’! WP Settings&  . Move the working plane around using  Utility Menu ’! Work Plane ’! Offset WP to&  . Align the working plane with various parts of the model using  Utility Menu ’! Work Plane ’! Align WP with&  . If you select more than one node or keypoint to offset the working plane to, it will go to the average location of the selected entities. VERY handy! Use the working plane to slice and dice your model. For example to cut an area in pieces use  Main Menu ’! Modeling ’! Operate ’! Booleans ’! Divide ’! Area by WrkPlane . Do this for lines and volumes as well. Select Logic: Selecting is an important and fundamental concept in ANSYS. Selected entities are your active entities. All operations (including Solving) are performed on the selected set. In many operations you select items  on the fly ; ANSYS prompts for what volumes to mesh for example, you pick them with the mouse, and ANSYS does the meshing. However there are many times when you need to select things in more sophisticated ways. Also, in an ANSYS input file or batch file you can t select things with the mouse! Examples where this would be useful: " You have many different areas at Z = 0 you want to constrain. You could select them all one by one when applying the constraint, or select  By Location beforehand, then say  Pick All in the picking dialog. " You have a structure with many fastener holes that you want to constrain. Again, you could select them all one by one when applying the constraint, or select lines  By Length/Radius , type in the radius of the holes to select all of them in one shot, then  Pick All in the picking dialog when applying the constraint. 7 © Copyright 2003 Belcan Engineering Group, Inc. After working with the selected set,  Utility Menu ’! Select ’! Everything to make the whole model active again. Select Entities Dialog Box Terminology: From Full: Select from the entire set of entities in the model. Reselect: Select a subset from the currently selected entities. Also Select: Select in addition to (from the whole model) the set you have currently selected. Unselect: Remove items from the selection set. Select All: This is not the same as  Utility Menu ’! Select ’! Everything . This selects all of whatever entity you have specified at the top of the dialog. Invert: Reverses the selected and unselected entities (just the entities specified at the top of the dialog). OK: This does the select operation (or brings up a picker dialog so that you can pick with the mouse) and then dismisses the dialog. Apply: This does the operation but keeps the dialog box. Typically use this so the dialog stays active. Replot: Replots whatever is active in the graphics window. Plot: Plots only the entity specified at the top of the dialog. Organizing Your Model Using Components: If you select a group of entities and think that you might want to use that selection set again, create a component out of it. Components are groups of entities but hold only one kind of entity at a time. Components can themselves be grouped into Assemblies, so this is how you group different types of entities together. Use  Utility Menu ’! Select ’! Comp/Assembly ’! Create Component&  to create a component. The new Component Manager in Release 8.0 makes it very easy to manage and manipulate groups and select/plot what you want to see to the screen. This is found under  Utility Menu ’! Select ’! Component Manager . 8 © Copyright 2003 Belcan Engineering Group, Inc. Creating a Material: Create the material properties for your model in  Main Menu ’! Preprocessor ’! Material Props ’! Material Models . This gives you this dialog box where all materials can be created, Double click on items in the right hand pane of this window to get to the type of material model you want to create. All properties can be temperature dependant. Click OK to create the material and it will appear in the left hand pane. Create as many different materials as you need for your analysis. Selecting an Element Type: ANSYS has a large library of element types. Why so many? Elements are organized into groups of similar characteristics. These group names make up the first part of the element name (BEAM, SOLID, SHELL, etc). The second part of the element name is a number that is more or less (but not exactly) chronological. As elements have been created over the past 30 years the element numbers have simply been incremented. The earliest and simplest elements have the lowest numbers (LINK1, BEAM3, etc), the more recently developed ones have higher numbers. The  18x series of elements (SHELL181, SOLID187, etc) are the newest and most modern in the ANSYS element library. Tell ANSYS what elements you are going to use in your model using  Main Menu ’! Element Type ’! Add/Edit/Delete . Later, when meshing or creating elements manually you will need to tell ANSYS what type of elements you want to create. See the Belcan  ANSYS Tips sheet called  Common Element Types for Structural Analysis for more information. 9 © Copyright 2003 Belcan Engineering Group, Inc. Creating Properties: A solid element (brick or tet) knows its thickness, length, volume, etc by virtue of its geometry, since it is defined in 3D space. Shell, beam and link (truss) elements do not know this information since they are a geometric idealization or engineering abstraction. Properties in ANSYS are called Real Constants. Define real constants using  Main Menu ’! Real Constants ’! Add/Edit/Delete . Later when meshing or creating elements manually ANSYS will need to know what real constant set you want to use for those elements. Creating the Finite Elements Model - Meshing: If you are just starting out in FEA, it is important to realize that your geometry (called the solid model in ANSYS) is not your finite element model. In the finite element method we take an arbitrarily complex domain, impossible to describe fully with a classical equation, and break it down into small pieces that we can describe with an equation. These small pieces are called finite elements. We essentially sum up the response of all these little pieces into the response of our entire structure. The solver works with the elements. The geometry we create is simply a vehicle used to tell ANSYS where we want our nodes and elements to go. While you can create nodes and elements one by one in a manual fashion (called direct generation in ANSYS) most people mesh geometry because it is much faster. Another very good reason we mesh geometry is that we assign materials and properties to that geometry. Then any element created on or in that geometric entity gets those attributes. If we don t like the mesh we can clear it and re-mesh, without having to re-assign the attributes. Steps for Creating the Finite Elements: 1. Assign Attributes to Geometry (materials, real constants, etc). 2. Specify Mesh Controls on the Geometry (element sizes you want). 3. Mesh. 10 © Copyright 2003 Belcan Engineering Group, Inc. Most of the meshing operations can be done within the MeshTool, so that will be examined in some detail now. Start it from  Main Menu ’! Preprocessor ’! Meshing ’! MeshTool . If you set global attributes, that material, element type, real constant, beam section, etc. will be used for all elements in the Smart Size is used to automatically pick model. It s better to use the drop down to the element edge length depending on assign different attributes to different the sizes of features in the geometry. It geometric entities in the model. Then mesh makes a finer mesh around smaller the whole model at one time. features in order to capture them adequately. For example in the mesh below no sizes were specified at all except a Smart Size level of 4. If you want to set a specific element edge length on an entity or tell ANSYS to put some specific number of elements along a line for example, use this. Y Pick what you want to mesh. Z X Shape of the element you want to create. For Volumes you would A mapped mesh generates a very regular have the choice of Hex or Tet. You grid of elements. This can only be used can create beam elements by on rectangular shaped areas or volumes. meshing lines. A free mesh will mesh any entity - regardless of shape. Brings up a picker dialog. You pick the entities to be cleared, press OK, Brings up a picker dialog. Pick the and ANSYS removes the nodes and entities to be meshed (or Pick All if elements from that geometry. you have made some selection using select logic), press OK, and ANSYS generates the nodes and elements on/in that geometry. Refine the mesh (make more nodes and elements locally) at a specific location (elements, nodes, kepoints, lines,etc.). How fine of a mesh should you have? Part of this is common sense. Put a finer mesh in areas of higher stress at stress gradient, like near a stress concentration. Do some simple experiments along with hand calculations; for point in the example I know I need about 30 nodes around a hole to model get a good value of the peak stress. Your stress you care convergence should follow a pattern as shown at right. about When the result is not changing much for a finer mesh, you have mesh convergence. number of nodes in the model 11 © Copyright 2003 Belcan Engineering Group, Inc. Applying Loads and Boundary Conditions: Loads and boundary conditions can be applied in both the Preprocessor ( Main Menu ’! Preprocessor ’! Loads ’! Define Loads ’! Apply ), and the Solution processor ( Main Menu ’! Solution ’! Define Loads ’! Apply ). 1. Select the kind of constraint you want to apply. 2. Select the geometric entity where you want it applied. 3. Enter the value and direction for it. There is no  modify command for loads and B.C. s. If you make a mistake simply apply it again with a new value (the old one will be replaced if it s on the same entity), or delete it and reapply it. Loads: Forces, pressures, moments, heat flows, heat fluxes, etc. Constraints: Fixities, enforced displacements, symmetry and anti-symmetry conditions, temperatures, convections, etc. Although you can apply loads and boundary conditions to nodes or elements, it s generally better to apply all B.C. s to your geometry. When the solve command is issued, they will be automatically transferred to the underlying nodes and elements. If B.C. s are put on the geometry, you can re-mesh that geometry without having to reapply them. Solving: Solution is the term given to the actual simultaneous equation solving of the mathematical model. The details of how this is done internally is beyond the scope of this guideline but is addressed in a separate  ANSYS Tips white paper. For the moment, it is sufficient to say that the basic equation of the finite element method that we are solving is, K u = F , where [K] is the assembled stiffness matrix of [ ]{ } { } the structure, {u} is the vector of displacements at each node, and {F} is the applied load vector. This is analogous to a simple spring and is the essence of small deflection theory. To submit your model to ANSYS for solving, go to  Main Menu ’! Solution ’! Solve ’! Current LS . LS stands for load step. A load step is a loading  condition . This is a single set of defined loads and boundary conditions (And their associated solution results. More on this in the next section). Within an interactive session the first solve you do is load step 1, the next solution is load step 2, etc. If you leave the solution processor after solving to do post-processing for example, the load step counter gets set back to one. You can also define and solve multiple load steps all at once. There are several solvers in ANSYS that differ in the way that the system of equations is solved for the unknown displacements. The two main solvers are the sparse solver and the PCG solver. If the choice of solvers is left to  program chosen then generally ANSYS will use the sparse solver. The PCG (preconditioned conjugate gradient) solver works well for models using all solid elements. From a practical perspective one thing to consider is that the sparse solver doesn t require a lot of RAM but swaps out to the disk a lot. Disk I/O is very slow. If you have a solid model and lots of RAM the PCG solver could be significantly faster since the solution runs mostly in core memory. 12 © Copyright 2003 Belcan Engineering Group, Inc. Postprocessing: The General Postprocessor is used to look at the results over the whole model at one point in time. This is the final objective of everything we have discussed so far; finding the stresses, deflections, temperature distributions, pressures, etc. These results can then be compared to some criteria to make an objective evaluation of the performance of your design. The solution results will be stored in the results file as result  sets . For a linear static analysis like we are talking about, the correlation between Load Step numbers and Results Set numbers will be one to one as shown below. Only one set of results can be stored in the database at a time, so when you want to look at a particular set, you have to read it in from the results file. Reading it in clears the previous results set from active memory. To read in a results set from the results file (not needed if you have run only a single load step) use  Main Menu ’! General Postproc ’! Read Results ’! First Set, or By Pick . Most results are displayed as a contour plot as shown below. To generate a plot of stresses use  Main Menu ’! General Postproc ’! Plot Results ’! Contour Plot ’! Nodal Solution , then pick the stresses you want to see. There are many, many other ways to look at your results data including: " Listing them to a file. " Querying with the mouse to find a result at a particular node. " Graphing results along a path. " Combining different load cases. " Summing forces at a point. " Extracting data and storing it an APDL array that you can do further operations with. Animate any result on the deformed shape with  Utility Menu ’! Plot Ctrls ’! Animate . This is very helpful for understanding if your model is behaving in a reasonable way. 13 © Copyright 2003 Belcan Engineering Group, Inc. Documenting your Analysis and Outputting Graphics: ANSYS has a Report Generator available from the main toolbar, which can help you put together an HTML report by capturing images, window listings, etc. To print a hardcopy of the graphics window:  Utility Menu ’! Plot Ctrls ’! Hard Copy ’! To Printer There are several ways of capturing a graphic image for use in Microsoft Word, Powerpoint or some other software. Exact screen shot of the graphics window:  Utility Menu ’! Plot Ctrls ’! Capture Image will pop up another window with a screen shot of your graphics window. You can keep it available for later reference or save the image to a bitmap (.bmp) file. Note that although a windows bitmap file is not compressed, when it is inserted into Word it does get compressed automatically so you don t end up with a huge bloated document. Output a vector image:  Utility Menu ’! Plot Ctrls ’! Redirect Plots ’! To PSCR File&  . A Postscript file is a vector file, which means that it is a 2D representation of all of the entities in the graphics window in an editable format. Because it is not a bitmap, it can be scaled to any size without losing any resolution, and is always very crisp looking. It can also be imported into a technical illustration program and manipulated very easily: change the colors, add annotations, change or resize fonts, etc. All this can be done in ANSYS but it can be quicker in an illustration package. One caution about Postscript files! Since they actually write out every entity in the model, if your model is large (say a tet mesh of a CAD model) this file can be huge. It is best suited for getting very crisp images of smallish models or wireframe displays. Microsoft Word will not display the image until it is printed. A very good free program to look at and manipulate Postscript files with (available on the web) is called  GSView . Output a bitmap image:  Utility Menu ’! Plot Ctrls ’! Redirect Plots ’! To xyz File&  , where xyz is JPEG, TIFF, PNG, etc. These file formats produce good images with reasonably small file sizes. The size of the image file for these formats is not dependant on the size of your model like Postscript. Note: The GRPH format is the ANSYS native image format. You can only deal with these files using the ANSYS DISPLAY program that is available from  Start Menu ’! Programs ’! ANSYS 8.0 ’! Display . This utility has some neat features like being able to take a group of static images you create and animating them into an mpeg or avi video. 14 © Copyright 2003 Belcan Engineering Group, Inc. Controlling the Way Your Model Looks: All of the visual aspects of what you see in the graphics window are controlled from the  Plot and  Plot Ctrls pull downs from the Utility menu. Use  Utility Menu ’! Plot to plot different types of entities to the screen. Use  Utility Menu ’! Plot Ctrls to control the characteristics of what you are plotting.  Utility Menu ’! Plot Ctrls ’! Numbering : Entity Numbers on and off.  Utility Menu ’! Plot Ctrls ’! Symbols : Turn various markers and symbols on and off. This is the most important button in this dialog, because it is not intuitive what this does. If you pick this and then click  OK at the bottom of this window, you will get three subsequent dialogs where you can turn the individual symbols on and off, as well as their values (the  All buttons above it will not show you the values, only the symbols). This is very commonly used to display just the force vectors along with their values on the model for documentation purposes (for example). Under  Reactions you can turn on the reaction vectors and their values as well as  free-body type forces. That is to say, the balancing forces acting on a node due to other elements attached to it but not selected.  Utility Menu ’! Plot Ctrls ’! Style : Change hidden line, element edges, element shrink, etc.  Utility Menu ’! Plot Ctrls ’! Device Options : Change between solid shaded and wireframe display. 15 © Copyright 2003 Belcan Engineering Group, Inc. ANSYS Parametric Design Language and Macros: APDL is the command language that drives ANSYS. Every GUI selection has a command equivalent that is executed when you click Apply or OK. All commands are well documented and if you know them you can type them in the command window instead of making a GUI selection. This can be faster than the mouse, but the real power of ANSYS is in easily automating tasks by stacking these commands into a text file and reading the file in to execute the commands all at once. Basic APDL commands are all laid out simply and in the same fashion, CommandName, argument1, argument2, argument3, argument4, etc. How do you know what the command equivalent is of a GUI operation? 1. Use the jobname.log file. A record of all your actions in ANSYS is kept here in the form of commands. Do an operation in the GUI, then open up that file and look at the last line to see the command used. 2. All GUI operations also give a hint to the command name, either in the dialog box itself or in the hint line. It s always given in square brackets. In the command window enter help,commandName to bring up detailed help for that command that describes what each argument is. [command name] Define parameter variables to use in your analysis with  Utility Menu ’! Scalar Parameters . Or just type in a variable using the equals sign in the command window. For example: Now you could refer to this variable in a dialog box and ANSYS will substitute the value of  pi . Use parameters and mathematical expressions in any entry box that requires a number. Handy! 16 © Copyright 2003 Belcan Engineering Group, Inc. APDL has much of the functionality of a full-featured programming language including mathematical functions and branching logic. Macros are APDL commands put into a file with a .mac extension. ANSYS will use these macros just like a regular ANSYS command. Here s a simple example, called edges.mac: C*** Reverses current display of all element edges C*** (if edges on, turns them off & vice versa) *GET,KEY,GRAPH,1,EDGE ! obtains current setting using a  *get command *IF,KEY,EQ,0,THEN /EDGE,1,1 ! sets KEY=1 *ELSE /EDGE,1,0 ! sets KEY=0 *ENDIF /REPLOT In the command line simply type: edges µ! to execute the macro. (note: µ! a" press ENTER) An analysis (building the model, solving, and postprocessing) can be completely defined using APDL commands and this does have some excellent benefits such as, " Your analysis is completely documented by your input file (you can add user comments as well). " You can use parameter variables to define dimensions or loading and have a parametric input file that you can run as many times as you want, changing the model each time by changing the variable values. Customizing the GUI: Another productivity enhancement that goes right along with APDL macros is customizing the abbreviation toolbar. Any ANSYS command or macro can be assigned to a toolbar button using the *ABBR command or  Utility Menu ’! MenuCtrls ’! Edit Toolbar . The format of the command is: *ABBR, name on the button, command Some examples of abbreviation button commands, *ABBR,WP-KP,KWPAVE,P ! move the working plane to avg of keyoints *ABBR,STR_LINE,L,P ! create a line between two points As you can see, the possibilities for customization of the toolbar to enhance productivity are limitless. To customize the location where dialog boxes pop up, arrange them how you want them to be the next time they appear, use  Utility Menu ’! MenuCtrls ’! Save Menu Layout . This saves the locations. Grab any of the solid bars that divide the main window panes and drag them to resize. The main graphics window does have a fixed aspect ratio however; you will notice this as you try to change it to a wide thin window for example. 17 © Copyright 2003 Belcan Engineering Group, Inc. Example - An Analysis of a Simply Supported Beam Using Three Methods: To demonstrate the general flow of an ANSYS simulation we will show an analysis of a simply supported beam under uniform pressure, analyzed with beam elements, shell elements, and solid elements. These results will be compared with a hand calculation which is also a good idea to confirm the results are reasonable. p t W beam section L Input data needed for this analysis: L = 12 in. W = 2 in. t = 0.125 in. p = 1.0 psi E = 10 e 6 psi ½ = 0.33 The running load for the beam model will be (1.0 psi)(23 wide) = 2.0 lb/in Theoretical Solution: 2 2 2 2 2 1 1 pbL2 (1.0 psi)(2.0 )(12 ) 3 2 2 2 2 I = bt3 = (2.0 )(0.125 ) = 0.000326 in4 M = = = 36 in Å"lbs 12 12 8 8 3 2 2 2 2 5pbL2 5(1.0 psi)(2.0 )(12 ) ´max = = 384EI 384(30e6 psi)(0.000326 in4)= 0.055296 in (36 in Å"lbs)ëø 0.1252 2 öø ìø ÷ø Mc 2 íø øø Ãmax = = = 6912 psi I 0.000326 in4 ANSYS Instructions: Beam Element Model Shell Element Model Solid Element Model Start ’! Programs ’! ANSYS 8.0 ’! Start ’! Programs ’! ANSYS 8.0 ’! Start ’! Programs ’! ANSYS 8.0 ’! Configure ANSYS Products. This Configure ANSYS Products. This Configure ANSYS Products. This starts the ANSYS Launcher. starts the ANSYS Launcher. starts the ANSYS Launcher. Click the File Management tab, select Click the File Management tab, select Click the File Management tab, select your working directory and change the your working directory and change the your working directory and change the jobname to beam1. jobname to beam2. jobname to beam2. Click Run in the Launcher to start Click Run in the Launcher to start Click Run in the Launcher to start ANSYS. ANSYS. ANSYS. Main Menu ’! Preferences ’! Main Menu ’! Preferences ’! Main Menu ’! Preferences ’! Structural. This filters out all Structural. This filters out all Structural. This filters out all disciplines except structural. disciplines except structural. disciplines except structural. 18 © Copyright 2003 Belcan Engineering Group, Inc. Beam Element Model Shell Element Model Solid Element Model Main Menu ’! Preprocessor ’! Main Menu ’! Preprocessor ’! Main Menu ’! Preprocessor ’! Element Type ’! Add/Edit/Delete. The Element Type ’! Add/Edit/Delete. The Element Type ’! Add/Edit/Delete. The first thing we do is tell ANSYS what first thing we do is tell ANSYS what first thing we do is tell ANSYS what kind of element we will be using for kind of element we will be using for kind of element we will be using for the analysis. the analysis. the analysis. In the Element Types dialog click Add In the Element Types dialog click Add In the Element Types dialog click Add ’! Beam ’! 3 node 189 ’! OK ’! ’! Shell’! 4noded181 ’! OK ’! ’! Solid ’! 20Node 186 ’! OK ’! Close. Close. Close. Create the Real Constant that will Create the material. Main Menu ’! Create the material. Main Menu ’! define the thickness of the shell Preprocessor ’! Material Props ’! Preprocessor ’! Material Props ’! elements. Main Menu ’! Preprocessor Material Models. Double click Material Models. Double click ’! Add/Edit/Delete ’! Add ’! Structural ’! Linear ’! Elastic ’! Structural ’! Linear ’! Elastic ’! Isotropic. Enter the values for the SHELL181 ’! OK ’! Enter 0.125 for Isotropic. Enter the values for the modulus (30e6) and Poisson s ratio modulus (30e6) and Poisson s ratio the thickness at Node I ’! OK ’! (0.33) ’! OK ’! Material ’! Exit. Close. (0.33) ’! OK ’! Material ’! Exit. Create a beam section with the Beam Create a solid block to represent the Create the material. Main Menu ’! Tool so that the real constants beam. Main Menu ’! Preprocessor ’! Preprocessor ’! Material Props ’! (properties) for the beam are Material Models. Double click Modeling ’! Create ’! Volumes ’! automatically calculated and applied. Structural ’! Linear ’! Elastic ’! Block ’! By Dimensions ’! {0,0,0} Main Menu ’! Preprocessor ’! Isotropic. Enter the values for the and {12,2,0.125} ’! OK. Sections ’! Beam Common Sections. modulus (30e6) and Poisson s ratio Fill out the form with the name of (0.33) ’! OK ’! Material ’! Exit. Start the MeshTool. Main Menu ’!  example for the section and B = 2 Preprocessor ’! Meshing ’! and H = 0.125 ’! Preview ’! OK. Create a rectangular area to represent MeshTool. the beam. Main Menu ’!Preprocessor ’! Modeling ’! Create ’! Areas ’! Assign element attributes to the volume. From the top of the MeshTool Rectangle ’! By Dimensions ’! {0,0} under element attributes pick Volumes and {12,2} ’! OK. and then Set. Pick the block and then OK in the picker dialog. For this Start the MeshTool. Main Menu ’! simple model with only one material, Preprocessor ’! Meshing ’! etc, we can accept the defaults and MeshTool. click OK. Assign element attributes to the area. Assign element sizes to the area before From the top of the MeshTool under meshing it. From Size Controls element attributes pick Areas and then section of the MeshTool pick Global Set. Pick the area and then OK in the Set. Pick the block and then OK in the picker dialog. For this simple model picker dialog. Enter 0.25 for the with only one real, material, etc, we Element Edge Length, OK. can accept the defaults and click OK. Create the brick elements in the Assign element sizes to the area before volume. From the MeshTool in the meshing it. From Size Controls Create keypoints; one for each end of Mesh section, Volumes ’! Hex ’! section of the MeshTool pick Areas the beam and one reference keypoint Mapped ’! Mesh Button ’! Pick the Set. Pick the area and then OK in the that will be used to tell ANSYS what volume ’! OK in the picker. picker dialog. Enter 0.5 for the the orientation of our beam is. Main Element Edge Length, OK. Menu ’! Preprocessor ’! Modeling ’! Use the Control key and the right Create ’! Keypoints ’! In Active CS. mouse button to rotate the model such Create the shell elements on the area. Create points at {0,0,0} ’! Apply, that the global Z-axis is pointing up for From the MeshTool in the Mesh {12,0,0} ’! Apply, and {0,1,0} ’! OK. a better view. section, Mapped ’! Mesh Button ’! Pick the area ’! OK in the picker. Create a line to represent the beam. 19 © Copyright 2003 Belcan Engineering Group, Inc. Beam Element Model Shell Element Model Solid Element Model Use the Control key and the right Apply simple support constraints to the Main Menu ’! Preprocessor ’! mouse button to rotate the model such ends of the beam. Main Menu ’! Modeling ’! Create ’! Lines ’! Lines that the global Z-axis is pointing up for Solution ’! Apply ’! Structural ’! ’! Straight Lines. Pick the end points a better view. of the line (keypoints 1 & 2), OK. Displacement ’! On Lines ’! Pick the bottom line at one end of the volume’! Display the shell thickness. Utility Turn on the keypoint numbers. Utility OK in the picker ’! click on All DOF Menu ’! PlotCntrls ’! Style ’! Size Menu ’!PlotCntrls ’! Numbering ’! ’! Apply ’! Pick the bottom line at the and Shape ’! Turn on  Display of Keypoints. other end of the beam ’! OK in the Element Shapes ’! OK. picker ’! click on UZ only ’! OK. Plot the lines and keypoints to the Apply simple support constraints to the screen. Utility Menu ’! Plot ’! Apply a pressure to the beam. Main ends of the beam. Main Menu ’! Multiplot. Menu ’! Solution ’! Apply ’! Solution ’! Apply ’! Structural ’! Structural ’! Pressure ’! On Areas ’! Start the MeshTool. Main Menu ’! Displacement ’! On Lines ’! Pick the Pick the top surface area of the block Preprocessor ’! Meshing ’! short lines at the ends of the area ’! ’! OK in the picker ’! Enter 1.0 for MeshTool. OK in the picker ’! click on UX ’! Pressure Value ’! OK. Apply ’! Pick the lines again ’! OK in Tell ANSYS what attributes to mesh the picker ’! click on UY ’! Apply ’! Utility Menu ’! PlotCntrls ’! Symbols the line with. At the top of the Pick the lines again ’! OK in the ’! Surface Load Symbols ’! Pressures MeshTool under  Element Attributes picker ’! click on UZ ’! OK. ’! Show pres and convect ’! Arrows select Lines from the drop down ’! ’! OK. Utility Menu ’! Plot ’! Set. Pick the line and OK in the Apply a pressure to the beam. Main Multiplot, to see the loads and B.C. s picking dialog. Since we have only Menu ’! Solution ’! Apply ’! on the line. one property we can accept all defaults Structural ’! Pressure ’! On Areas ’! except click the  Pick Orientation Pick All ’! OK in the picker ’! Enter Save the model. Utility Menu ’! File Keypoint(s) checkbox to Yes ’! OK. -1.0 for Pressure Value ’! OK. ’! Save Jobname.db. Pick keypoint 3 as the orientation keypoint. Utility Menu ’! PlotCntrls ’! Symbols Solve the model. Main Menu ’! ’! Surface Load Symbols ’! Pressures Solution ’! Solve ’! Current LS. Assign element sizes to the line before ’! Show pres and convect ’! Arrows Review and close the  /STATUS meshing it. From Size Controls ’! OK. Utility Menu ’! Plot ’! window ’! OK in the Solve dialog. section of the MeshTool pick Lines Multiplot, to see the loads and B.C. s Set. Pick the line and then OK in the on the line. Plot the displacements. Main Menu ’! picker dialog. Enter 1.0 for the General Postproc ’! Plot Results Element Edge Length, OK. Save the model. Utility Menu ’! File ’!Contour Plot ’! Nodal Solution ’! ’! Save Jobname.db. Create the beam elements on the line. DOF Solution ’! USUM ’! OK. From the MeshTool, Mesh ’! Pick the Solve the model. Main Menu ’! line ’! OK in the picker. Max Displacement = 0.05553 Solution ’! Solve ’! Current LS. Review and close the  /STATUS Change to an Oblique view. From the Plot the stresses. Main Menu ’! window ’! OK in the Solve dialog. View toolbar on the RHS of the General Postproc ’! Plot Results ’!Contour Plot ’! Nodal Solution ’! graphics window click . Plot the displacements. Main Menu ’! Stresses ’! X-direction SX ’! OK. General Postproc ’! Plot Results Display the beam section on the line. ’!Contour Plot ’! Nodal Solution ’! Utility Menu ’! PlotCntrls ’! Style ’! DOF Solution ’! USUM ’! OK. Size and Shape ’! Turn on  Display of Element Shapes ’! OK. Max Displacement = 0.05483 Apply constraints to the ends of the Plot the stresses. Main Menu ’! beam. Main Menu ’! Solution ’! General Postproc ’! Plot Results Apply ’! Structural ’! Displacement ’!Contour Plot ’! Nodal Solution ’! ’! On Keypoints ’! Pick the end Stresses ’! X-direction SX ’! OK. keypoints of the line ’! OK in the picker ’! click on UX, UY, UZ, and Max Stress = 6931 psi ROTX ’! OK. 20 © Copyright 2003 Belcan Engineering Group, Inc. Beam Element Model Shell Element Model Solid Element Model Apply a running load to the top of the beam. Main Menu ’! Solution ’! Apply ’! Structural ’! Pressure ’! On Beams ’! Pick All ’! OK in the picker ’! Enter 2.0 for Pressure Value ’! OK. Utility Menu ’! PlotCntrls ’! Symbols ’! Surface Load Symbols ’! Pressures ’! Show pres and convect ’! Arrows ’! OK. Utility Menu ’! Plot ’! Max Stress = 6896 psi Multiplot, to see the loads and B.C. s on the line. Save the model. Utility Menu ’! File ’! Save Jobname.db. Solve the model. Main Menu ’! Solution ’! Solve ’! Current LS. Review and close the  /STATUS window ’! OK in the Solve dialog. Plot the displacements. Main Menu ’! General Postproc ’! Plot Results ’!Contour Plot ’! Nodal Solution ’! DOF Solution ’! USUM ’! OK. Max Displacement = 0.05533 Plot the stresses. Main Menu ’! General Postproc ’! Plot Results ’!Contour Plot ’! Nodal Solution ’! Stresses ’! X-direction SX ’! OK. Max Stress = 6944 psi 21 © Copyright 2003 Belcan Engineering Group, Inc. Appendix A - Example 1 Analysis APDL Input File: ! ANSYS Quick Start Guide: Beam 1 Example ! Paul Dufour ! Belcan Corporation ! December 2003 finish /clear /PREP7 ! Enter ANSYS preprocessor !!!!! PARAMETERS !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! To change the model we can simply change these here. modulus=30e6 poissons=0.33 beam_length=12 beam_width=2 beam_height=0.125 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !Define element type to be used: BEAM189, three noded quadratic beam ET,1,BEAM189 ! Material is steel MPTEMP,,,,,,,, MPTEMP,1,0 MPDATA,EX,1,,modulus MPDATA,PRXY,1,,poissons ! Create the geometric keypoints K,,,,, K,,beam_length,,, ! This one will be the orientation keypoint K,,0,1,, ! Draw the line LSTR,1,2 /auto ! fit the view ! Create the beam section SECTYPE,1,BEAM,RECT,example,0 SECOFFSET, CENT SECDATA,beam_width,beam_height,0,0,0,0,0,0,0,0 ! Assign attributes to the line LATT,1,,1,,3,,1 ! Sepcify the element sizes LESIZE,all,1.0 ! Mesh the line with beam elements LMESH,1 /ESHAPE,1.0 ! turn on the beam shape finish ! exit the preprocessor /solu ! enter the solution module ! Constrain the ends of the beam DK,1,,,,0,UX,UY,UZ,ROTX DK,2,,,,0,UX,UY,UZ,ROTX ! Apply the running load to the beam elements 22 © Copyright 2003 Belcan Engineering Group, Inc. SFBEAM,all,1,PRES,2.0 solve ! submit the model to ANSYS for solving finish ! exit the solution module /post1 ! Enter the general post-processor ! plot the loads and b.c.'s on the model /PSF,PRES,NORM,2,0,1 /PBC,ALL,,1 /PBC,NFOR,,0 /PBC,NMOM,,0 /PBC,RFOR,,0 /PBC,RMOM,,0 /PBC,PATH,,0 ! plot the deflection PLNSOL,U,SUM,0,1 ! plot the stresses in the beam PLNSOL,S,X,0,1 ! store the maximum plotted stress value in a parameter variable *get,maxstress,plnsol,0,max ! Oblique view /VIEW,1,1,2,3 /ANG,1 /REP,FAST ! all done 23 © Copyright 2003 Belcan Engineering Group, Inc. Appendix B  ANSYS and General FEA References: 1. Moaveni, S.,  Finite Element Analysis: Theory and Applications with ANSYS , 2nd Edition, Prentice Hall, 2003. 2. Lawrence, K.L.,  ANSYS Tutorial (Release 7.0) , Schroff Development Corp. Publications, 2002. 3. Adams, V., and Askenazi, A.,  Building Better Products with Finite Element Analysis , Onward Press, Sante Fe, NM, 1999. 4. Cook, R.D., Malkus, D.S., and Plesha, M.E.,  Concepts and Applications of Finite Element Analysis , 3rd Edition, John Wiley and Sons, New York, 1989. 5. Segerlind, L.J.,  Applied Finite Element Analysis , John Wiley and Sons, New York, 1976. 6. Smith, I.M., and Griffiths, D.V.,  Programming the Finite Element Method , 2nd Edition, John Wiley and Sons, New York, 1988. (This edition uses FORTRAN77 in its examples.) 7. Smith, I.M., and Griffiths, D.V.,  Programming the Finite Element Method , 3nd Edition, John Wiley and Sons, New York, 1997. (This edition uses Fortran 90 in its examples.) 8. Zienkiewicz, O.C.,  The Finite Element Method , 3rd Edition, McGraw-Hill Book Company Limited, London, 1977. 9. Bathe, K.J.,  Finite Element Procedures , Prentice Hall, 1996. 24 © Copyright 2003 Belcan Engineering Group, Inc. Appendix C  ANSYS and General FEA Web Sites: ANSYS Information ANSYS Web Site - ANSYS Inc. Home Page. General information regarding the always growing ANSYS family of products. (www.ansys.com) ANSYS.net - More commonly know as "Sheldons Site". ANSYS Macro & Info Repository by Sheldon Imaoka. The best ANSYS site on the web. Huge collection of ANSYS stuff with contributions by users all over the world. Great! (www.ansys.net/ansys) ANSYS Tips Page - Many ANSYS pointers and a ton of FEA links, some related to ANSYS and some general. By Peter Budgell. Hasn't been updated in a few years but most info is still very applicable to ANSYS currently. (www3.sympatico.ca/peter_budgell/home.html) ANSYS Tutorials - From the University of Alberta, Canada. This is a very well done and complete set of tutorials categorized from basic to advanced. (www.mece.ualberta.ca/tutorials/ansys/index.html) XANSYS.org - Home of the XANSYS list. This is a mailing list of ANSYS users from around the world with 2500+ members. (www.xansys.org) General Finite Element Analysis Finite Element Modeling Continuous Improvement - Site at NASA Goddard Space Flight Center. (analyst.gsfc.nasa.gov/FEMCI/femci.html) NAFEMS - A European Engineering Analysis Organization. The "Analysis Resources" section has a lot of good info and links. (www.nafems.org) FEA Links Page - many links to finite element resources. Updated in 2003. (www.engr.usask.ca/%7Emacphed/finite/fe_resources/fe_resources.html) FEMur - Finite Element Method Universal Resource at WPI (Worcester Polytechnic Institute) (femur.wpi.edu) Introduction to FEA by Dermot Monaghan - Although a couple parts are under construction, this guy has put together a really nice FEA site here. (www.dermotmonaghan.com) 25 © Copyright 2003 Belcan Engineering Group, Inc.

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