|Published on:||December 3rd, 2018|
|With:||Eric Miller & Joe Woodward|
In this episode your host and Co-Founder of PADT, Eric Miller is joined by PADT’s Specialist Mechanical Engineer, Joe Woodward to discuss how eigenvalue buckling can effect the load factor of a structure, and what applications it has for a variety of different projects. All that, followed by an update on news and events in the respective worlds of ANSYS and PADT.
For more information on this topic and some visual representation of what is being discussed, check out the blog post that inspired this episode here:
If you have any questions, comments, or would like to suggest a topic for the next episode, shoot us an email at firstname.lastname@example.org we would love to hear from you!
Importing solid 3D Mechanical CAD (or MCAD) models into ANSYS HFSS has always been and remains to be a fairly simple process. After opening ANSYS Electronics Desktop and creating an HFSS design, from the menu bar, select Modeler > Import. A dialog box will open to navigate to and directly open the model.
The CAD will automatically be translated and loaded into the HFSS 3D Modeler. If the geometry is correct and does not require any editing, the import process is complete and analysis can begin! However, if there are any errors with the geometry, there is excessive or invalid detail, or if it’s not organized into separate bodies conducive for electromagnetic analysis, you may soon realize that the editing capability is limited to scaling, reorienting, or Boolean operations. This approach can be particularly troublesome when portions of the model (or all of the model) which consist of different materials are not split into different objects. For example, notice the outer conductor, inner conductor, and dielectric of the imported SMA below are all one solid object.
Unless you’re lucky enough to work with the creator of the CAD, you will need to find a way to split this model into the inner and outer conductors, and the dielectric. However, since the release of ANSYS R18.1, the power of SpaceClaim Direct Modeler (SCDM) and the MCAD translator will be packaged together. The good news is, the process described above will continue to work. The better news is, SCDM offers new capabilities to directly edit or clean imported geometry. So, here are a few simple steps to quickly split this SMA connector using SCDM. You can download a copy of this model here to follow along. If you need access to SCDM, you can contact us at email@example.com. It’s worth noting, at this point, that the processes discussed throughout this article work the same for HFSS-IE, Q3D, and Maxwell designs as well.
 First, after opening ANSYS SpaceClaim, the step file can be imported through the menu File > Open or by simply dragging and dropping the file into the SCDM window.  To separate the dielectric from the outer conductor, select Design > Intersect > Split Body.  Click and hold the center mouse button to rotate the model so the boundary between the dielectric and outer conductor is visible. Hold the Ctrl key and click the center mouse button to pan, and use the center mouse scroll to zoom in and out. Finally, press ‘z’ on the keyboard to fit the view window.  When positioned, click on the object to split (in this case it is the entire model).  Then, click on the face which defines the boundary between the dielectric and outer conductor.  Finally, press the Esc key. The first split is done!
Repeat the Split Body process to separate the center conductor from the dielectric. Notice under the structure tree that there are now three separate objects.
The split body function is also useful to simplify a structure for analysis. For example, the female side of the SMA could be simplified as a solid center conductor.  Reposition the connector to view the female side. - Control the visibility of each body with the object’s checkbox in the structure tree.  Measure the length of the female side by pressing the letter ‘e’ on the keyboard and selecting the top edge (note the line length of 2.95mm for later).  Then, repeat the Split Body process to split the center conductor at the boundary between the male and female sides. - However, rather than pressing the Esc key, click on the female receiver to automatically remove the body.
 To extend the center pin to its original length, select Design > Edit > Pull.  Click on the face where the female side was originally attached and select the Up To option.  Type in the previously measured length of 2.95mm.  Finally, press Enter (press Esc 3x to exit the Pull command).
Repeat the Split Body and Pull processes until the model has been divided into different bodies for each material type and is sufficiently simplified.
Once the model is ready, select File > Save As to save the geometry as the preferred format. Perhaps the most familiar approach to HFSS users would be to save the new model as a STEP file, then to import the model into HFSS as described in the first paragraph.
The ANSYS App Store contains all sorts of free and paid apps developed by ANSYS as well as trusted partners. These apps improve workflows and allow users to build in best practices. An app that has been of particular interest to me is Workbench Poly Meshing for Fluent.
This app enables the power and capacity of Fluent Meshing, most notably the polyhedral meshing feature, with the ease of use of the ANSYS Workbench Meshing environment. In order to show the functionality of this app, I will demonstrate with the generation of a polyhedral mesh on a sample geometry from the Fluent Meshing tutorials.
To start out, I have imported a .igs file of an exhaust manifold into ANSYS SpaceClaim Direct Modeler, which has powerful repair and prepare tools that will come in handy. I notice that the geometry is comprised of 250 surfaces, which I need to fix in order to create a solid body. By navigating into the ‘Repair’ tab and selecting the ‘Stitch’ operation, SpaceClaim notes there are two stitchable edges in my geometry. I select the green check mark to perform this operation and am greeted with a solid geometry. I complete my tasks in SpaceClaim by extracting the fluid volume using the ‘Volume Extract’ tool in the ‘Prepare’ tab.
I setup my workflow in ANSYS workbench with my added ‘Fluent Meshing’ ACT module between the ‘Mesh’ module and ‘Fluent’ module. I can then proceed to create my desired surface mesh in ANSYS meshing and setup a few required inputs for Fluent Meshing.
Once this process has been completed, I can update my ‘Fluent Meshing’ cell and open the ‘Fluent’ setup cell to display my polyhedral mesh!
IMPORTANT NOTE: all named selections must be lowercase with no spaces, and the file path(s) cannot contain any spaces.
We here at PADT are proud to present the ease of use and productivity enhancements that have been added to ANSYS Mechanical in release 18.
With this new release, ANSYS Mechanical focuses on the introduction of a variety of improvements that help save the users time, such as smarter data organization and new hotkeys, along with additions that can help you to better visualize specific intricacies in your models.
Join PADT’s Simulation Support & Application Engineer Doug Oatis for an overview of the current user friendly interfaces within ANSYS Mechanical, along with the numerous additions in this new release that help to improve efficiency tenfold, such as:
Register today to find out how you can use these enhancements to improve your throughput and stay ahead of the curve!
We look forward to seeing you there.
After playing with that block it seems like it may be time to try a more complex geometry. For business banking, I’ve got this key fob that generates a number every thirty seconds that I use for security when I log in. Might as well sort of model that.
So the first thing I do is start up a new model and orient myself on to the sketch plane:
Then I use the line and arc tools to create the basic shape. Play around a bit. I found that a lot of things I had to constrain in other packages are just assumed when you define the geometry. A nice thing is that as you create geometry, it locks to the grid and to other geometry.
I dragged around and typed in values for dimensions to get the shape I wanted. As I was doing it I realized I was in metric. I’m old, I don’t do metric. So I went in to File and selected SpaceClaim options from the bottom of the window. I used the Units screen to set things to Imperial.
This is the shape I ended up with:
I took this and pulled it up and added a couple of radii:
But if I look at the real object, the flat end needs to be round. In another tool, I’d go back to the sketch, modify that line to be an arc, and regen. Well in SpaceClaim you don’t have the sketch, it is gone. Ahhh. Panic. I’ve been doing it that way for 25 some years. OK. Deep breath, just sketch the geometry I need. Click on the three point arc tool, drag over the surface, then click on the first corner, the second, and a third point to define the arc:
Then us pull to drag it down, using the Up to icon to lock it to the bottom of the object.
Then I clicked on the edges and pulled some rounds on there:
OK, so the next step in SolidEdge would be to do a thin wall. I don’t see a thin wall right off the top, but shell looks like what I want, under the Create group on the Design tab. So I spinned my model around, clicked on the bottom surface I want to have open and I have a shell. A thickness of 0.035″ looks good:
My next feature will be the cutout for the view window. What I have not figured out yet is how to lock an object to be symmetrical. Here is why. I sketch my cutout as such, not really paying attention to where it is located. Now I want to move it so that it is centred on the circle.
Instead of specifying constraints, you move the rectangle to be centered. To do that I drag to select the rectangle then click Move. By default it puts the nice Move tool in the middle of the geometry. If I drag on the X direction (Red) you can see it shows the distance from my start.
So I have a couple of options, to center it. The easiest is to use Up To and click the X axis for the model and it will snap right there. The key thing I learned was I had to select the red move arrow or it would also center horizontally where I clicked.
If I want to specify how far away the edge is from the center of the circle, the way I did it is kind of cool. I selected my rectangle, then clicked move. Then I clicked on the yellow move ball followed by a click on the left line, this snapped the move tool to that line. Next I clicked the little dimension Icon to get a ruller, and a small yellow ball showed up. I clicked on this and dragged it to the center of my circle, now I had a dimension from the circle specified that I could type in.
After playing around a bit, if found a second, maybe more general way to do this. I clicked on the line I want to position. One of the icons over on the left of my screen is the Move Dimension Base Point icon. If you click on that you get another one of those small yellow balls you can move. I dragged it over to the center of the circle and clicked. then I can specify the distance as 0.75″
I’ve got the shape I want, so I pull, using the minus icon to subtract, and I get my cutout:
If you look closely,you will notice I put rounds on the corners of the cutout as well, I used Pull again.
The last thing I want to do is create the cutout for where the bank logo goes. It is a concentric circle with an arc on the right side. Saddly, this is the most complex thing I’ve ever sketched in SpaceClaim so I was a bit afraid. It was actually easy. I made a circle, clicking on the center of the outside arc to make them concentric. The diameter was 1″. Then I made another circle of 2″ centered on the right. To get the shape I wanted, I used the Trim Away command and clicked on the curves I don’t want. The final image is my cutout.
Now I can do the same thing, subtract it out, put in some rounds, and whalla:
Oh, and I used the built in rendering tool to quickly make this image. I’ll have to dedicate a whole posting to that.
But now that I have my part, it is time to play with move in 3D.
Tyler, who is one of our in-house SpaceClaim experts (and younger) pointed out that I need to start thinking about editing the 3D geometry instead of being obsessed with controlling my sketches. So here goes.
If I wanted to change the size of the rectangular cutout in a traditional CAD tool, I’d go edit the sketch. There is no sketch to edit! Fear. Unknown. Change.
So the first thing I’ll do is just move it around. Grab one of the faces and see happens.
It moves back and forth, pretty simple. The same tools for specifying the start and stop points are available. Now, if I ctrl-click on all four surfaces the whole thing moves. That is pretty cool.
Note: I’m using the undo all the time to go back to my un-moved geometry.
Another Note: As you select faces, you have to spin the model around a lot. I use the middle mouse button to do this rather than clicking on the spin Icon and then having to unclick it.
That is enough for this post. More soon.
As I explored ANSYS SpaceClaim in my first try, it became obvious that a lot of capabilities that are in multiple operations in most CAD systems, are all combined in Pull for SpaceClaim. In this posting I feel like it would be a really good idea for me to really understand all the things Pull can do.
Not very exciting or adventurous. But there is so much in this operation that I feel like I will miss something critical if I don’t read up first. It states:
“Use the Pull tool to offset, extrude, revolve, sweep, and draft faces; use it to round, chamfer, extrude, copy, or pivot edges. You can also drag a point with the Pull tool to draw a line on a sketch plane.”
Let’s think about that for a second. What it is basically saying is if I pull on an object of a given dimension, it creates an object that is one higher dimension. Point pulls to a curve, a curve pulls to a face, and a face pulls to a solid. Kind of cool. The big surprise for me is that there is no round or fillet command. To make a round you pull on an edge. This is change.
I started by reading my block with a hole back in.
This fillet pull thing scares me so I thought I’d confront it first. So selecte Pull, and selected an edge:
Then I dragged it away from the block. Nothing. You can’t create a surface that way. Then I dragged in towards the center. A round was created.
If anything, too simple. Back in my day, adding a round to an edge took skill and experience!
So next I think I want to try and change the size of something. Maybe the diameter of the hole. So I select the cylinder’s face. Is shows the current radius. I could just change that value:
Instead I drag, and while I do that I noticed that there are two numbers, the current radius and the change to the radius! Kind of cool. No, really useful.
You use tab to go between them. So I hit tab once, typed 3 then tab again (or return) and I get a 8 mm diameter. I like the visual feedback as well as the ability to enter a specific change number.
Next thing that I felt like doing was rounding a corner. Put a 5mm round on the corner facing out:
So I grabbed the point and dragged, and got a line.
Remember, it only goes up one entity type – point to curve. Not point to surface. So I ctrl-clicked (that is how you select multiple entities) on the three curves that intersect at the corner:
Then I dragged and got my round.
This are all sort of dragging straight. After looking at the manual text it seems I can revolve and sweep as well with the Pull operation. Cool. But what do I revolve or sweep around and along? Looking at the manual (and it turns out the prompt on the screen) I use Alt-Clicking to define these control curves. Let’s try it out by revolving something about that line I mistakenly made.
I click on one of the curves on the round. then Alt-Click the line – It turns blue. So there is a nice visual clue that it is different than the source curve. Now I’ve also got spinny icons around the curve rather than pull icons.
So I drag and… funky revolved surface shows up. I had to spin the model to see it clearly:
Let me stop and share something special about this. In most other CAD tools, this would have involved multiple clicks, maybe even multiple windows. In SpaceClaim, it was Click, Alt-Click, Drag. Nice.
Using the Pop=up Icons
As you play with the model you may start seeing some popup icons near the mouse when you select geometry while using pull. The compound round on the block is complicated, so I spun it around and grabbed just one edge and pulled it in to be a round. Then I clicked on it and got this:
Not only can I put a value in there, I can drop ones I use a lot. I can also change my round to a chamfer, or I can change it to a variable radius. This is worth noting. In most other CAD tools you pick what type of thing you want to do to the edge. Here we start by dragging a round, then specify if it is a chamfer or a variable.
The variable radius is worth digging more in to. I clicked on it and it was not intuitive as to what I should do. Let’s try help. Search on Variable Radius… duh. Click on the arrow that shows up and drag that. There are three arrows. The one in the middle scales both ends the same, the one on either end, well it sets the radius for either end.
Clicking on a control point and hitting delete, gets rid of them.
That’s just one icon that pops up. Playing some more it seems the other icons control how it handles corners and multiple fillets merging… something to look at as I do more complex parts.
The other popup I want to look at is the Up To one. It looks like an arrow on a surface. In other tools I extrude, cut, revolve all the time to some other piece of geometry. This is the way to do it in Space Claim. Let’s say I want to pull a feature to the middle of my hole. First I sketch the outline on a face:
That is enough for pulling and for today. In the next session it may be time to explore the Move command.
This post is a table of contents to a series about ANSYS SpaceClaim. After over 31 years of CAD use, it has become difficult for me to learn new tools. In this series I will share my experience as I explore and learn how to use this fantastic tool.
Thirty-one. That is the number of years that I have been using CAD software. CADAM was the tool, 1985 was the year. As some of our engineers like to point out, they were not even born then.
Twenty-one. that is the number of years that I have been using SolidEdge. This classifies me as an old dog, a very old dog. As PADT has grown the amount of CAD I do has gone way down, but every once in a while I need to get in there and make some geometry happen. I’m usually in a hurry so I just pop in to SolidEdge and without really thinking, I get things done.
Then ANSYS, Inc. had to go and buy SpaceClaim. It rocks. It is not just another solid modeler, it is a better way to create, repair, and modify CAD. I watch our engineers and customers do some amazing things with it. I’m still faster in SolidEdge because I have more years of practice than they have been adults. But this voice in my head has been whispering “think how fast you would be in SpaceClaim if you took the time to learn it.” Then that other voice (I have several) would say “you’re too old to learn something new, stick with what you know. You might break your hip”
I had used SpaceClaim a bit when they created a version that worked with ANSYS Mechanical four or five years ago, but nothing serious. Last month I attended some webinars on R17 and saw how great the tool is, and had to accept that it was time. That other voice be damned – this old dog needs to get comfortable and learn this tool. And while I’m at it, it seemed like a good idea to bring some others along with me.
These posts will be a tutorial for others who want to learn SpaceClaim. Unlike those older tools, it does not require five days of structured training with workshops. The program comes with teaching material and tutorials. The goal is to guide the reader through the process, pointing out things I learned along the way, as I learn them.
A link to the table of contents is here.
The product I’m learning is ANSYS SpaceClaim Direct Modeler, a version of SpaceClaim that is built into the ANSYS simulation product suite. There is a stand alone SpaceClaim product but since most of our readers are ANSYS users, I’m going to stick with this version of the tool.
This is what you see when you start it up:
I’ve been using the same basic layout for 20 years, so this is a bit daunting for me. I like to start on a new program by getting to know what different areas of the user interface do. The “Welcome to ANSYS SCDM” kind of anticipates that and gives me some options.
Under “Getting Started” you will see a Quick Reference Card, Introduction, and Tutorials. Open up the Quick Reference and print it out. Don’t bother with it right now, but it will come in handy, especially if you are not going to use SpaceClaim every day.
The Introduction button is a video that gets you oriented with the GUI. Just what we need. It is a lot of information presented fast, so you are not going to learn everything the first viewing, but it will get you familiar with things.
Here I am watching the video. Notice how attentive I am.
Once that is done you should sort of know the basic lay of the land. Kind of like walking into a room and looking around. You know where the couch is, the window, and the shelf on one wall. Now it is time to explore the room.
It is kind of old school, but I like user guides. You can open the SpaceClaim User Guide from the Help line in the “Welcome” window. I leave it open and use it as a reference.
The best place to learn where things are in the interface is to look at the interface section in the manual. It has this great graphic:
The top bit is pretty standard, MS office like. You have your application menu, quick access toolbar, and Ribbon Bar. The Ribbon Bar is where all the operations sit. We used to call these commands but in an object oriented world, they are more properly referred to as operations – do something to objects, operate on them. I’ll come back and explore those later. Over on the left there are panels, the thing we need to explore first because they are a view into our model just like the graphics window.
The Structure Panel is key. This is where your model is shown in tree form, just like in most ANSYS products. In SpaceClaim your model is collection of objects, and they are shown in the tree in the order you added them. You can turn visibility on and off, select objects, and act on objects (using the right mouse button) using the tree. At this point I just had one solid, so pretty boring. I’m sure it will do more later.
Take a look at the bottom of the Structure Panel and you will find some tabs. These give access to Layers, Selection, Groups, and Views. All handy ways to organize and interact with your model. I felt like I needed to come back to these later when I had something to interact with.
TIP: If you are like me, you probably tried to drag these panels around and hosed up your interface. Go to File > SpaceClaim Options (button at the bottom) > Appearance and click the “Reset Docking Layout” button in the upper right of the window. Back to normal.
The options panel changes dynamically as you choose things from the ribbon. If you click on the Design > Line you get this:
And if you click on Pull you get this:
Keeps the clutter down and makes the commands much more capable.
Below that is the Properties Panel. If the Options panel is how you control an operation, then the Properties panel is how you view and control an object in your model. No point in exploring that till we have objects to play with. It does have an appearance tab as well, and this controls your graphics window.
At the bottom is the Status Bar. Now I’m a big believer in status bars, and SpaceClaim uses theirs well. It tells you what is going on and/or what to do next. It also has info on what you have selected and short cut icons for selection and graphics tools. Force yourself to read and use the status bar, big time saver.
The last area of the interface is the graphics window. It of course shows you your geometry, your model. In addition there are floating tools that show up in the graphics window based upon what you are doing. Grrr. #olddogproblem_1. I’m not a fan of these, cluttering up my graphics. But almost all modern interfaces work this way now and I will have to overcome my anger and learn to deal.
For most of the 30+ years that I’ve been doing this CAD thing, I’ve always started with the same object: A block with a hole in it. So that is what we will do next. I have to admit I’m a little nervous.
I’m nervous because I’m a history based guy. If you have used most CAD tools like SolidWorks or ANSYS DesignModeler you know what history based modeling is like. You make a sketch then you add or subtract material and it keeps track of your operations. SpaceClaim is not history based. You operate on objects and it doesn’t track the steps, it just modifies your objects. SolidEdge has done this for over ten years, but I never got up the nerve to learn how to use it. So here goes, new territory.
Things start the same way. But instead of a sketch you make some curves. The screen looks like this when you start:
The default plane is good enough, so I’ll make my curves on that. Under Design>Sketch click on the Rectangle icon then move your mouse on to the grid. You will notice it snaps to the grid. Click in the Upper Left and the Lower Right to make a rectangle then enter 25mm in to each text box, making a 25 x 25 square:
Next we want to make our block. In most tools you would find an extrude operation. But in SpaceClaim they have combined the huge multitude of operations into a few operation types, and then use context or options to give you the functionality you want. That is why the next thing we want to do is click on Pull on the Edit group.
But first, notice something important. If you look at the model tree you will notice that you have only one object in your design, Curves. When you click Pull it gets out of sketch mode and into 3D mode. It also automatically turns your curves into a surface. Look at the tree again.
This is typical of SpaceClaim and why it can be so efficient. It knows what you need to do and does it for you.
Move you mouse over your newly created surface and notice that it will show arrows. Move around and put it over a line, it shows what object will be selected if you click. Go to the inside of your surface and click. It selects the surface and shows you some options right there.
Drag your mouse over the popup menu and you can see that you can set options like add material, subtract material, turn off merging (it will make a separate solid instead of combining with any existing ones), pull both directions, get a ruler, or specify that you are going to pull up to something. For now, we are just going to take the default and pull up.
As you do this the program tells you how far you are pulling. You can type in a value if you want. I decided to be boring and I put in 25 mm. Geometry has been created, no one has been hurt, and I have not lost feeling in any limbs. Yay.
On the status bar, click on the little menu next to the magnifying glass and choose Zoom Extents. That centers the block. Whew. That makes me feel better.
Now for the hole. It is the same process except simpler than in most tools. Click on the circle tool in Sketch. The grid comes back and you can use that to sketch, or you can just click on the top of the block. Let’s do that. The grid snaps up there. To make the circle click in the middle of the grid and drag it out. Put 10 in for the diameter. A circle is born.
Now choose Pull from the Edit section. There is only a Solid now?
SpaceClaim went ahead and split that top surface into two surfaces. Saving a step again.
Click on the circle surface and drag it up and down. If you go up, it adds a cylinder, if you go down, it automatically subtracts. Go ahead and pull it down and through the block and let go. Done. Standard first part created. Use the File>Save command to save your awesome geometry.
That is it for the getting started part. In the next post we will use this geometry to explore SpaceClaim more, now that we have an object to work on. As you were building this you probably saw lots of options and input and maybe even played with some of it. This is just a first look at the power inside SpaceClaim.
Click here for Post 2 where the Pull command is explored.
The following is a story of discovery. The discovery of an ANSYS feature that has been around since at least ANSYS14! How is that possible you ask? The PADT team members are the ANSYS experts of the Southwest, how could they have missed this! And we would agree with you on the former, but even we overlook some of the most fundamental and helpful features. And you are going to want to store this one away, so copy the link, bookmark the page, or make a mental note with your photographic memory and file it under productivity enhancer.
After all of that hype, what could I possibly be going tell you that is so earth shattering. Well, it’s not really a secret if you read the title but I’ll let you be the judge of this little nugget’s seismic impact. Now, if you’ll indulge me, I’ll set the stage.
A couple of weeks ago, I was compiling a report of an ANSYS Mechanical analysis. One of the report sections required details of the contact definition between each part. I hunkered down to spend what I thought would be a tedious hour of documenting each contact expecting to use a procedure that consisted in some form of isolating the two bodies of interest, capturing screenshots of the two parts in various relation to each other in order to adequately represent the contact context. As I sat looking at the screen creating my plan of attack, I thought to myself, I wish there was an ANSYS feature that would automatically isolate the two connected bodies so that I would not have to go through the finger numbing (or should I say finger cramping) task of “hiding all other bodies” (even though this is one of my other favorite features). As soon as the thought flashed through my mind, my eyes moved up the screen and, above the Mechanical graphics window, I saw it.
Body Views! The star of my post. You will find our elusive capability in the painfully obvious Connections Context Toolbar:
When I clicked on it, the graphics window transformed from this:
The relevant bodies were isolated into two different views, contact and target. I was elated. My task of manually isolating the bodies and adjusting the views while intermediately capturing the desired screens now turned into a joyful, albeit nerdy, moment of discovery. With some experimenting, I easily found that each view can be adjusted independently, unless of course you would like them all to move together. You can accomplish this by selecting the Sync Views option:
Why this feature is helpful:
Summary of steps to enable the Body Views feature:
To my chagrin, this option has been available in ANSYS for a few releases at least and I never took note. But the possibility that some of you might have also overlooked this option prompted me to highlight it for you and I hope you find it useful in the future.
If you found this article helpful and are interested in learning about or being reminded of some other excellent ANSYS time saver capabilities, check out the article by Eric Miller on filtering and tagging here.
I got some errors when I imported my geometry.
I have some holes and stray surfaces in my geometry.
The edges are twisting around on my geometry import.
ANSYS blows up when I’m trying to mesh my imported geometry.
What geometry format are you using?
The vast majority of the time, geometry import errors are attributable to the choice of geometry format. And that choice is IGES. To understand the problems with IGES, it helps to know a little bit of IGES history.
IGES, which stands for Initial Graphics Exchange Specification, was released in 1980 as a neutral format for sharing data between CAD systems. The most recent version, 5.3 came out in 1996.
IGES: The “Izzy” of geometry formats
Besides being old, there are a few other problems with this format:
Generally speaking, IGES is typically the worst geometry format to import into ANSYS.
Now that I’ve trashed IGES, here is what I recommend:
ANSYS offers several native geometry readers, such as Connections for Pro/E, NX, Solidworks, SolidEdge, etc. that bring in geometry directly from the CAD modeler. There are two advantages here:
The only catch when it comes to native geometry readers is that they require a separate license. However, about 90% of the tech support calls I’ve received about IGES import errors are from people who have licenses for native geometry readers and just aren’t using them.
Even if you have a native geometry reader license, you’ll need to be sure to check the box to install the reader during ANSYS installation. You may also need to use the CAD Configuration Manager (found in the Utilities folder in the ANSYS start menu) to configure the CAD reader if you didn’t do so during installation.
The one unfortunate exception to this is CATIA. The CATIA kernel is a bit more guarded than the other CAD kernels, and this is frequently noted in CATIA geometry import errors. Also, you can only import CATIA geometry, not associate to it as with other CAD tools.
Your ANSYS installation comes with the capabilities to import both IGES and STEP files without having to purchase an additional geometry connection license. Of the two, STEP is typically the better option. There are two reasons for this:
You may also have licenses for Parasolid and/or ACIS readers, which can lead to some confusion as to which format to use. This is easily addressed by considering the underlying geometry kernel for the originating CAD tool*.
I said geometry kernel, not…oh never mind… mmmm… fried chicken….
For example, SolidEdge, NX, and Solidworks all use the Parasolid kernel. Therefore the most robust neutral format for geometry exported from these tools will generally be Parasolid (.x_t or .x_b extension), of course. Likewise, AutoCAD uses the ACIS kernel, indicating that ACIS (.sat file) will usually be the best neutral geometry format in this case. For CAD tools that use neither of these kernels, STEP will typically be the best neutral format.
As you can see, even though the IGES people know how to make acronyms, IGES is typically the last geometry format you want to try when importing or associating geometry to ANSYS. This doesn’t mean that IGES is always the worst option for reading in CAD files (especially compared to the CATIA connection), just that it usually is.
*Hat tip to Robin Steed of ANSYS, Inc. for this tip