It shows how to modify the legend to get just what you want, how to save the settings to a file, and then how to use those seettings again on a different model. Very simple and Powerful.
It shows how to modify the legend to get just what you want, how to save the settings to a file, and then how to use those seettings again on a different model. Very simple and Powerful.
At PADT we provide help to many of our customers who have trouble with their ANSYS simulations. At the top level, though, there are some computer skills for Windows that we consider basics that every engineer should know. If these are skills you already have in your tool belt, fantastic! If not, hopefully this information will help you be more effective in your simulation tasks.
Also, since most of us have been or are currently being updated to Windows 10, I’m providing the instructions for Windows 10. Windows 7 is similar, though.
This allows us to run programs, a.k.a. “apps” with administrator privilege, even if our login credentials don’t allow this level of usage. This is the case for most users of engineering software. Certain components of ANSYS, including the CAD Configuration Manager and the Client ANSLIC_ADMIN Utility require changes to your computer that non-admin rights won’t allow. By running as administrator, we allow the program to make the needed changes.
To do this, click the Start Menu, then find the program (app) you need to run in the resulting list, such as the Client ANSLIC_ADMIN Utility, but one important thing to keep is mind is to use a privacy filter, it is important to maintain your privacy. Next, right click on that program, select More with the left mouse button, then select Run as Administrator with the left mouse button. If you are prompted to allow changes to your system, click Yes. Here is what it will look like:
When using Windows Explorer, now known as File Explorer in Windows 10, by default you probably won’t see file extensions. Instead, you’ll see the prefix of files, but won’t see the endings of the file names. This will be the case when browsing for files to open or save as well. Sometimes you can rely on the icons associated with a file to know which program it’s associated with or the Type field in the list view, but sometimes there are conflicts. For example, an ANSYS Mechanical APDL macro file will have the extension .mac. You can probably guess that there is at least one other major company that can have software that uses that extension. By viewing the file extensions, even if the icons are wrong, we can more easily identify the files we need. Here is how it’s done:
Click Start, then File Explorer:
The default view using “Details” in File Explorer will look something like this (file names don’t include extensions):
To view the extensions, we click on the View menu in File Explorer, then Options, then Change Folder and Search Options.
The way I set this option for all folder on my computer is to then click on the View tab in the resulting small window, then uncheck the box for Hide extensions for known file types, then click Apply to Folders, then click OK.
Now the list view (using Details under the View menu) in File Explorer looks like this, with each file showing its extension in the list:
Environment Variables are values that are used by certain programs to define settings. For example, an environment variable can be used to specify the license server for certain programs. It’s good to know how to define and edit these if needed. To do this, we bring up the control panel. In Windows 10, click on the Start button, then Settings:
A quick way to get there is to type “environment” in the search window in the resulting Settings window:
The search should find Edit the System Environment Variables. Click on that:
In the resulting System Properties window, click on the Environment Variables button in the Advanced tab:
A new window will open with a list of currently defined User variables (just for your login) and System variables (for anyone who is logged in), like this:
You can click on an environment variable to edit it using the Edit… button, or you can click on the New… button to create a new one. One ANSYS-related environment variable that occasionally needs to be set is ANSYSLMD_LICENSE_FILE. This is only needed if the default license server specifications aren’t working for some reason. You won’t need to set this under normal circumstances. Just in case, here is how to define it, using the New… button under System variables. We type in the Variable Name, in this case ANSYSLMD_LICENSE_FILE and then the Variable Value, which in this example is 1055@myserver.
When done defining and editing environment variables, we click on the OK button to complete the action and get out of that environment variable-related windows.
As simulation experts, we are often pushing the limits of our computer resources. It’s good to know how to check those. First is disk space. An easy way to check disk space is to bring up File Explorer again. Click on This PC on the left side. This will give you a snapshot of the available space on each hard drive that is accessible on this computer:
Next, we may want to check CPU or memory utilization. Perhaps we want to make sure that our solution is running on multiple cores as we have requested.
To do this, hold down the Alt, Control, and Delete keys on the keyboard, all at the same time. Then click on Task Manager in the resulting window (it will look for a second like your computer is going to restart – it won’t actually do that).
In the resulting Task Manager window, click on More details:
In the resulting window, we can click on the Performance tab and view, for example, the current memory utilization, or we can click on Open Resource Monitor and get even more details, including utilization on each CPU:
It’s very common in the simulation world to end up filling up your disk drives. Therefore, it’s good to be able to find large files so we can delete them if they are no longer needed. For a simple way to do this, we’ll start with File Explorer again. This time, we’ll click in the search window at upper right, but won’t actually type in anything. We just want the search tools menu to appear:
Next, click on Search under Search Tools, followed by Size, then Gigantic (I will argue that 128 MB isn’t all that gigantic in the simulation world, but Microsoft hasn’t caught up with us yet):
Windows will now perform a search for files larger than 128 GB. If any of these are no longer needed, you can right click and delete them. Just make sure you don’t delete any files that are truly needed!
That completes our discussion on 5 computer skills every engineer should know. In conclusion, these basic skills should help you be more productive over time as you perform your simulation tasks. We hope you find this information useful, if it is is not enough, than visit this website for more infromation.
Also read: Windows SQL Server by SaveOnIT.Com.
Some of you have probably already noticed, but ANSYS Mechanical licenses have some changes at version 17. First, the license that for years has been known as ANSYS Mechanical is now known as ANSYS Mechanical Enterprise. Further, ANSYS, Inc. has enabled significantly more functionality with this license at version 17 than was available in prior versions. Note that the license task in the ANSYS license files, ‘ansys’ has not changed.
|16.2 and Older (task)||17.0 (task)|
|ANSYS Mechanical (ansys)||ANSYS Mechanical Enterprise (ansys)|
The 17.0 ANSYS License Manager unlocks additional capability with this license, in addition to the existing Mechanical structural/thermal abilities. Previously, each of these tools used to be an additional cost. The change includes other “Mechanical-” licenses: e.g. Mech-EMAG, Mech CFD. The new tools enabled with ANSYS Mechanical Enterprise licenses at version 17.0 are:
|Fatigue Module||Rigid Body Dynamics||Explicit STR||Composite PrepPost (ACP)|
|SpaceClaim||DesignXplorer||ANSYS Customization Suite||AQWA|
Additionally, at version 17.1 these tools are included as well:
These changes do not apply to the lower level licenses, such as ANSYS Structural and Professional. In fact, these licenses are moving to ‘legacy’ mode at version 17. Two newer products now slot below Mechanical Enterprise. These newer products are ANSYS Mechanical Premium and ANSYS Mechanical Pro. We won’t explain those products here, but your local ANSYS provider can give you more information on these two if needed.
Getting back to the additional capabilities with Mechanical Enterprise, these become available once the ANSYS 17.0 and/or the ANSYS 17.1 license manager is installed. This assumes you have a license file that is current on TECS (enhancements and support). Also, a new license task is needed to enable Simplorer Entry.
Ignoring Simplorer Entry for the moment, once the 17.0/17.1 license manager is installed, the single Mechanical Enterprise license task (ansys) now enables several different tools. Note that:
Here is a very brief summary of these newly available capabilities:
Overcoming convergence difficulties in nonlinear structural problems can be a challenge. I’ve written a couple of times previously about tools that can help us overcome those difficulties:
I’m pleased to announce a new tool in the ANSYS Mechanical tool belt in version 17.0.
With version 17.0 of ANSYS we get a new meshing option for structural simulations: Nonlinear Mechanical Shape Checking. This option has been added to the previously available Standard Mechanical Shape Checking and Aggressive Mechanical Shape Checking. For a nonlinear solution in which elements can become significantly distorted, if we start with better-shaped elements they can undergo larger deformations without encountering errors in element formulation we may encounter fewer difficulties as the nodes deflect and the elements become distorted. The nonlinear mechanical setting is more restrictive on the element shapes than the other two settings.
We’ve been recommending the aggressive mechanical setting for nonlinear solutions for quite a while. The new nonlinear mechanical setting is looking even better. Anecdotally, I have one highly nonlinear customer model that reached 95% of the applied load before a convergence failure in version 16.2. That was with the aggressive mechanical shape checking. With 17.0, it reached 99% simply by remeshing with the same aggressive setting and solving. That tells you that work has been going on under the hood with the ANSYS meshing and nonlinear technology. By switching to the new nonlinear mechanical shape checking and solving again, the solution now converges for the full 100% of the applied load.
Here are some statistics using just one measure of the ‘goodness’ of our mesh, element quality. You can read about the definition of element quality in the ANSYS Help, but in summary better shaped elements have a quality value close to 1.0, while poorly shaped elements have a value closer to zero. The following stats are for tetrahedral meshes of a simple turbomachinery blade/rotor sector model (this is not a real part, just something made up) comparing two of the options for element shape checking. The table shows that the new nonlinear mechanical setting produces significantly fewer elements with a quality value of 0.5 or less. Keep in mind this is just one way to look at element quality – other methods or a different cutoff might put things in a somewhat different perspective. However, we can conclude that the Nonlinear Mechanical setting is giving us fewer ‘lower quality’ elements in this case.
|Shape Checking Setting||Total Elements||Elements w/Quality <0.5||% of elements w/Quality <0.5|
Here are images of a portion of the two meshes mentioned above. This is the mesh with the Aggressive Mechanical Shape Checking option set:
The eyeball test on these two meshes confirms fewer elements at the lower quality contour levels.
And this is the mesh with the Nonlinear Mechanical Shape Checking option set:
So, if you are running nonlinear structural models, we urge you to test out the new Nonlinear Mechanical mesh setting. Since it is more restrictive on element shapes, you may see longer meshing times or encounter some difficulties in meshing complex geometry. You may see a benefit in easier to converge nonlinear solutions, however. Give it a try!
I had a very cool music teacher back in 6th or 7th grade in the 1970’s in upstate New York. Today we’d probably say she was eclectic. In that class we listened to and discussed fairly recent songs in addition to general music studies. Two songs I remember in particular are ‘Hurdy Gurdy Man’ by Donovan and ‘Pinball Wizard’ by The Who. If you’re not familiar with Pinball Wizard, it’s from The Who’s rock opera Tommy, and is about a deaf, mute, blind young man who happens to be adept at the game of pinball. Yes, he is a Pinball Wizard. This sing popped into my head recently when we had some customer questions here at PADT regarding the pinball region concept as it pertains to ANSYS contact regions.
I’m not sure if the developers at ANSYS, Inc. had this song in mind when they came up with the nomenclature for the 17X (latest and greatest) series of contact elements in ANSYS, but regardless, you too can be a pinball wizard when it comes to understanding contact elements in ANSYS Mechanical and MAPDL.
Fans of this blog may remember one of my prior posts on contact regions in ANSYS that also had a musical theme (bringing to mind Peter Gabriel’s song “I Have the Touch”):
In this current entry we will go more in depth on the pinball region, also known as the pinball radius. The pinball region is involved with the distance from contact element to target element in a given contact region. Outside the pinball region, ANSYS doesn’t bother to check to see if the elements on opposite sides of the contact region are touching or not. The program assumes they are far away from each other and doesn’t worry about any additional calculations for the most part.
Here is an illustration. The gray elements on the left represent the contact body and the red elements on the right represent the target body (assuming asymmetric contact). Target elements outside the pinball radius will not be checked for contact. The contact and target elements actually ‘coat’ the underlying solid elements so they are shown as dashed lines slightly offset from the solid elements for the sake of visibility. Here the pinball radius is displayed as a dashed blue circle, centered on the contact elements, with a radius of 2X the depth of the underlying solid elements.
So, outside the pinball region, we know ANSYS doesn’t check to see if the contact and target are actually in contact. It just assumes they are far away and not in contact. What about what happens if the contact and target are inside the pinball region? The answer to that question depends on which contact type we have selected.
For frictionless contact (aka standard contact in MAPDL) and frictional contact, the program will then check to see if the contact and target are truly touching. If they are touching, the program will check to see if they are sliding or possibly separating. If they are touching and penetrating, the program will check to see if the penetration exceeds the allowable amount and will make adjustments, etc. In other words, for frictionless and frictional contact, if the contact and target elements are close enough to be inside the pinball region, the program will make all sorts of checks and adjustments to make sure the contact behavior is adequately captured.
The other scenario is for bonded and no separation contact. With these contact types, the program’s behavior when the contact and target elements are within the pinball region is different. For these types, as long as the contact and target are close enough to be within the pinball region, the program considers the contact region to be closed. So, for bonded and no separation, your contact and target elements do not need to be line on line touching in order for contact to be recognized. The contact and target pairs just need to be inside the pinball region. This can be good, in that it allows for some ‘slop’ in the geometry to be automatically ignored, but it also can have a downside if we have a curved surface touching a flat surface for example. In that case, more of the curved surface may be considered in contact than would be the case if the pinball region was smaller. This effect is shown in the image below. Reducing the pinball radius to an appropriate smaller amount would be the fix for eliminating this ‘overconstraint’ if desired.
There is a default value for the pinball region/radius. It can be changed if needed. We’ll add more details in a moment. First, why is it called the “pinball” region? I like to think it’s because when it’s visualized in the Mechanical window, it looks like a blue pinball from an actual pinball arcade game, but I’ll admit that the ANSYS terminology may predate the Mechanical interface. The image below shows what I mean. The blue balls are the different pinball radii for different contact regions.
Note that you don’t see the pinball region displayed as shown in the above image unless you have manually changed the pinball size in Mechanical. The pinball region can be changed in the Mechanical window in the details view for each contact region by changing Pinball Region from Program Controlled to Radius, like this:
In MAPDL, the pinball radius value can be changed by defining or editing the real constant labeled PINB.
By now you’re probably wondering what is the default value for the pinball radius? The good news is that it is intelligently decided by the program for each contact region. The default is always a scale factor on the depth of the underlying elements of each contact region. In the first pinball region image shown near the beginning of this article, the example plot shows the pinball region/radius as two times the depth of the underlying elements.
The table below summarizes the default pinball radius values for most circumstances for 2D and 3D solid element models. More detailed information is available in the ANSYS Help.
|Default Pinball Radius Values||Large Deflection Off|
|Large Deflection On
|Frictionless and Frictional||1* Underlying Element Depth||2*Underlying Element Depth|
|Bonded and No Seperation||0.25*Underlying Element Depth||0.5*Underlying Element Depth|
|Rigid-Flexible Contact: Typically the Default Values are Doubled|
Summing it all up: we have seen how the default values are calculated and also how to change them. We have seen what they look like as blue balls in a plot of contact regions in Mechanical if the pinball radius has been explicitly defined. We also discussed what the pinball radius does and how it’s different for frictionless/frictional contact and bonded/no separation contact.
You should be well on your way to becoming a pinball wizard at this point.
Does performing simulation in ANSYS make you think of certain songs, or are there songs you like to listen to while working away on your simulations an addition to The Who’s “Pinball Wizard” and Peter Gabriel’s “I Have the Touch”? If so, we’d love to hear about your song preferences in the comments below.
It seems like I’ve been explaining large deflection effects a lot recently. Between co-teaching an engineering class at nearby Arizona State University and also having a couple of customer issues regarding the concept, large deflection in structural analyses has been on my mind.
Before I explain any further, the thing you should note if you are an ANSYS Mechanical simulation user is this: If you don’t know if you need large deflection or not, you should turn it on. There is really no way to know for certain if it’s needed or not unless you perform a comparison study with and without it.
So, what are large deflection effects? In simple terms the inclusion of large deflection means that ANSYS accounts for changes in stiffness due to changes in shape of the parts you are simulating. The classic case to consider is the loaded fishing rod.
In its undeflected state, the fishing rod is very flexible at the tip. With a heavy fish on the end of the line, the rod deflects downward and it is then easy to observe that the stiffness of the rod has increased. In other words, when the rod is lightly loaded, a small amount of force will cause a certain downward deflection at the top. When the rod is heavily loaded however, a much larger amount of force will be needed to cause the tip to deflect downward by the same amount.
This change in the force amount required to achieve the same change in displacement implies that we do not have a linear relationship between force and displacement.
Consider Hooke’s law, also known as the spring equation:
F = Kx
Where F is the force applied, K is the stiffness of the structure, and x is the deflection. In a linear system, doubling the force results in double the displacement. In our fishing rod case, though, we have a nonlinear system. We might need to triple the force to double the displacement, depending on how much the rod is loaded relative to its size and other properties, and then to double the displacement again we might need to apply four times that force, just using numbers out of my head as examples.
So, in the case of the fishing rod, Hooke’s law in a linear form does not apply. In order to capture the nonlinear effect we need a way for the stiffness to change as the shape of the rod changes. In our finite element solution in ANSYS, it means that we want to recalculate the stiffness as the structure deflects.
This recalculation of the stiffness as the structure deflects is activated by turning on large deflection effects. Without large deflection turned on, we are constrained to using the linear equation, and no matter how much the structure deflects we are still using the original stiffness.
So, why not just have large deflection on by default and use it all the time? My understanding is that since large deflection adds computation expense to have it on, it’s off by default. It’s the same as for a lot of advanced usage, such as frictionless or frictional contact vs. the default bonded (simpler) behavior. In other words, turning on large deflection will trigger a nonlinear solution, meaning multiple passes through the solver using the Newton Raphson method instead of the single pass needed for a linear problem.
Here is an example of a simplified fishing rod. The image shows the undeflected rod (top), which is held fixed on the left side and has a downward force load applied on the right end. The bottom image shows the final deflected shape, with large deflection effects included. The deflection at the tip in this case is 34 inches.
In comparison running the same load with large deflection turned off resulted in a tip deflection of 40 inches. Thus, the calculated tip deflection is 15% less with large deflection turned on, since we are now accounting for change in stiffness with change in shape as the rod deflects.
Below we have a force (horizontal axis) vs. deflection (vertical axis) plot for a nonlinear simulation of a fishing rod with large deflection turned on. The fact that the curve is not a straight line confirms that this is a nonlinear problem, with the stiffness (slope of the curve) not constant. We can also see that as the force gets higher, the slope of the curve is more horizontal, meaning that more force is needed for each incremental amount of displacement. This matches our observations of the fishing rod behavior.
So, getting back to our original point, it’s often the case that we don’t know if we need to include large deflection effects or not. When in doubt, run cases with and without. If you don’t see a change in your key results, you can probably do without large deflection.
Here is an example using an idealized compressor vane. In this case, the deflections and stresses with and without large deflection effects are nearly the same (the stress difference is about 0.2%).
Bottom line: when in doubt, try it out, with and without large deflection. In ANSYS Mechanical, Large Deflection effects are turned on or off in the details of the Analysis Settings branch.
It’s worth noting that turning on large deflection in ANSYS actually activates four different behaviors, known as large deflection which include large rotation, large strain, stress stiffening, and spin softening. All of these involve change in stiffness due to deformation in one way or another.
If you like this kind of info, or find it useful, we cover topics like this in our training classes. For more info, check out our training pages at http://www.padtinc.com/support/software/training.html.
ANSYS PExpert is a fantastic tool for the design, modeling, and analysis of transformers and inductors. Using a combination of classical and finite element analysis (FEA) techniques, ANSYS PExprt determines the core size and shape, air gaps, and winding strategy for a given power converter topology. What we and our customers have found very useful is the ability to then evaluate the magnetic design in ANSYS Maxwell to view such things as flux density in the core and current density distribution in the windings. Powerful stuff.
The first step in implementing ANSYS PExprt with ANSYS Maxwell is installing and configuring them correctly. We created a step-by-step guild for our ANSYS customers here in the Southwest, and thought others would find it useful.
If you have ever dreamed of, or at least had a need for a 3D .pdf file of your simulation results, the dream is now realized thanks to VCollab. As Eric Miller mentioned in The Focus blog back in February, the latest release of VCollab software enables users to save their results in 3D .pdf format.
We’ve now had a chance to test out the capability here at PADT, and we find it quite useful. We’ve talked about VCollab before, but it’s a software suite that enables virtual collaboration (hence the name) by reducing what may be huge simulation files to a much smaller size, enabling others in your organization or your customers to dynamically view simulation results as well as CAD data in a light-weight viewer. The folks at Vcollab have gone one step beyond that now by supporting the 3D .pdf format that is viewable in the standard Adobe reader.
Vcollab works with ANSYS results as well as results from lots of other simulation tools. The process is:
You can download the sample file used in the images below:
This is what a typical 3D .pdf file created from an ANSYS Mechanical/MAPDL results file looks like, with using the mouse to rotate and zoom around within Adobe reader.
So, if you recognize value in being able to create 3D .pdf files like this, the Vcollab software suite is worth investigating. Vcollab does lots of useful things besides writing 3D .pdf files, including the capability to be imbedded within the ANSYS Engineering Knowledge Manager (ANSYS EKM) tool.
The best way to see the power of this tool is to request a demo. Just fill out this form and we will reach out and set one up, followed by a 30 day trial. .
Or check out www.vcollab.com.
I found another very nice enhancement to version 16.0 of the ANSYS Workbench/ANSYS Mechanical toolset. If you happen to have a NASTRAN input file (.dat, .nas, and .bdf) that you need to get into ANSYS Mechanical, no longer do you have to use FE Modeler in ANSYS Workbench to perform the translation. In fact, not only can you move the NASTRAN model into ANSYS Mechanical, but you get the existing mesh as well as newly-created geometry that can be used for boundary condition application, etc. As with most translations from one FE tool to another, you can’t expect everything will be translated. However, this new technique can be an incredible time saver in addition to giving us capabilities to continue and augment simulations that were previously performed in NASTRAN, now in ANSYS.
Here is an example of this new procedure. (Note that we don’t have NASTRAN here at PADT, so I couldn’t create a generic sample of a NASTRAN model in NASTRAN. Instead, I created a model in ANSYS, then converted it into NASTRAN using ANSYS FE Modeler to get a NASTRAN input file for the purpose of this exercise.)
Once I have the NASTRAN input file that I need to convert into ANSYS Mechanical, I launch ANSYS Workbench 16.0 and insert an External Model branch. I then click the … button to browse to the NASTRAN input file. In this case, the file is NASTRAN.nas.
Next, I drag and drop a new analysis type block into the Project Schematic. In this case, it was a modal analysis. Note that you can’t drop this onto the Setup cell in the External Model block as you might expect. You set it up as a separate block and establish the link in the next step.
Next, we drag and drop the Setup cell from the External Model block onto the Model cell of the Modal analysis block. This establishes the link from the NASTRAN model to the new Modal analysis.
We also need to right click on the Setup cell in the External Model block and select Update to get a green checkmark in that cell:
Notice that there is no Geometry cell in the resulting Modal analysis block. If all goes well, there will be geometry within the Mechanical model that can be used for selection purposes (in addition to the mesh that comes in from NASTRAN).
Next we open the Mechanical editor by double clicking on one of the cells in the Modal analysis blocks (other than the Engineering Data cell). It may take several minutes to bring in the NASTRAN model depending on the size of the NASTRAN model. The Mechanical window doesn’t really let you know that it’s working, but if it’s sitting there with nothing being displayed, it’s probably churning away at bringing in the NASTRAN mesh and creating surface geometry on it.
Here is what the Mechanical window looks like after the mesh is read in and geometry is automatically created. This is the mesh from the NASTRAN file, but in this case both solid and surface geometry is also present. It’s not guaranteed that everything will come across. I’ve seen contact elements come through for certain types of contact but not for other types of contact for example.
The next image shows that geometry was created that can be used for the purposes of inserting fixed supports, just as if the geometry had come in from a CAD system. Note that the NASTRAN input file had NO geometry, just finite element entities. ANSYS is creating the geometry for use in Mechanical from the information in the NASTRAN input file.
Finally, after manually creating a needed contact region, I was able to solve the modal analysis, demonstrating that further simulation can be performed in ANSYS Mechanical from this model which originally came from NASTRAN.
So, the main take away here is that with version 16.0 of ANSYS, we can take a NASTRAN input file and through the use of the External Model block, go directly into ANSYS Mechanical. Not only do we get the nodes and elements as well as other finite element entities from the NASTRAN model, but if all goes well we get geometry that facilitates further processing within ANSYS Mechanical.
We certainly hope this new capability makes it easier for you to perform additional simulations in ANSYS when the starting point is a NASTRAN model. The other formats documented for version 16.0 are ABAQUS, Fluent input files, and ICEM CFD input files.
If your role includes administering ANSYS licenses, you should be aware that the look and feel of the ANSYS license manager has changed somewhat at version 16.0. The tasks that used to all be performed within the Server ANSLIC_ADMIN Utility have now been split pretty much between that tool and a new tool that runs within your browser called the ANSYS License Management Center.
The ANSYS License Management Center looks like this:
This new License Management Center window is opened on Windows via Start > All Programs > ANSYS, Inc. License Manager > ANSYS License Management Center, and on Linux via /ansys_inc/shared_files/licensing/start_lmcenter.
This utility is where you now install license files, start and start the license manager, and also gather diagnostic information if something goes wrong. You can also view the license .log files here as well as ANSYS licensing documentation.
The ‘old’ Server ANSLIC_ADMIN Utility is now smaller and does less than it did in prior versions. This is what it looks like at version 16.0:
This window is still useful in that you can click on View Status/Diagnostic Options to get information you can’t get in the new License Management Center, primarily Display the License Status to see what licenses are in use and are available. This information is also available to clients via the Client ANSLIC_ADMIN Utility. You can start the ANSYS License Management Center from here too.
One capability you won’t find in either utility is the ability to Reread the License Manager settings. When you load a new license file, the License Management Center now automatically stops and starts the license manager so you shouldn’t have to do a reread after installing a new file, but just in case, it can still be done via the command line using these instructions:
On Windows, open a command prompt and move to:
C:\Program Files\ANSYS Inc\Shared Files\Licensing\winx64
Then issue the command:
ansysli_server –k reread
The same command works on Linux from the /ansys_inc/shared_files/licensing/linx64 directory.
Another important change is the location of the license files after they have been installed. The new location is (on Windows):
C:\Program Files\Ansys Inc\Shared Files\Licensing\license_files
This means there is a new sub-folder named license_files that contains the license file(s). File(s) is now plural since you can have both an ANSYS license file and an Ansoft license file in that folder, both running using the ANSYS License Management Center. There is a new license file naming convention as well:
ANSYS License file name: ansyslmd.lic
ANSOFT License file name: ansoftd.lic
The path on Linux is:
When you install an ANSOFT license file, the license manager now does some edits to change the daemon to the ANSYS daemon in addition to renaming the file and placing it in the new location.
One additional piece of information: The license manager reads any .lic files that are located in the license_files folder, so it’s probably a good idea to ensure that only ‘good’ versions of ansyslmd.lic and ansoftd.lic reside in that folder.
A major conclusion that can be drawn from all of this is that ANSYS license manager and Ansoft license manager license files can now be managed using a single licensing tool and single set of licensing software. We’ve been waiting for this for some time and it’s nice to see it’s here and working successfully.
PADT is excited about the plethora of new features in release 16.0 of ANSYS products. After sorting through the list of new features in Mechanical, here are 10 enhancements that we found to be particularly useful for general applications.
This new option in the details view for the mesh branch makes it easy to visualize mesh quality items such as aspect ratio, skewness, element quality, etc. The default style is body color, but it can be changed in the details to element quality, for example, as shown here:
Figure 1. A. – Mesh Display Style Set to Element Quality
Figure 1. B. – Element Quality Plot After Additional Mesh Settings
Figure 1. C. – Accessing Display Style in the Mesh Details
How many times have you either done a print screen > paste into editing tool > crop or done an image to file to get the plots you need into tools such as Word and PowerPoint? The new Image to Clipboard menu pick streamlines this process. Now, just get the image the way you want it in the geometry view, right click, and select Image to Clipboard. Or just use Ctrl + C. When you paste, you’ll be pasting the contents of that view window directly. Here’s what it looks like:
Figure 2 – Right Click, Image to Clip Board
This was a beta feature at 15.0, but if you didn’t get a chance to try it out, it’s now fully supported at 16.0. The idea here is that instead of the ‘traditional’ bonded contact methods (using the augmented Lagrange or pure penalty formulation) or the Multi-Point Constraint (MPC) bonded option, we now have a new choice of beam contact. This option utilizes internally-created massless linear beam elements to connect the two sides of a contact interface together. This can be more efficient than the traditional formulations and can avoid the over constraints that can happen if multiple contact regions utilizing the MPC option end up generating constraint equations that tend to conflict with each other.
Figure 3 – Beam Formulation for Bonded Contact
If you have ever been frustrated by the error message in the Solution Information window that says, “Element xyz … has become highly distorted…”, version 16.0 adds a new tool to our toolbox with the Nonlinear Adaptive Region capability. This capability is in its infancy stage at 16.0, but in the right circumstances it allows the solution to recover from highly distorted elements by pausing, remeshing, and then continuing. We plan on publishing more details on this capability soon, but for now please know that it exists and more can learned in the 16.0 Mechanical Help. There are a lot of restrictions on when it can work, but a big one is that it only works for elements that become overly deformed due to large and nonuniform deformation, meaning not due to unstable materials, numerical instabilities, or structures that are unstable due to buckling effects.
As shown in figure 4. A., a Nonlinear Adaptive Region can be inserted under the Solution branch. It is scoped to bodies. Options and controls are set in the details view.
Figure 4. A. – Nonlinear Adaptive Region
If the solver encounters a ‘qualifying event’ that triggers a remesh, the solver output will inform us like this:
Results item tabular listings will show that a remesh has occurred, as shown in figure 4. B.
Figure 4. B. – Results Table Indicating a Remesh Occurred in the Nonlinear Adaptive Region
Figure 4. C. – Before and After Remesh Due to Nonlinear Adaptive Region
This has also been a beta option in prior releases, but nicely, at 16.0 it becomes a production feature. The idea here is that we can use the ANSYS Mechanical APDL FLUID116 elements in Mechanical, without needing a command object. These fluid elements have temperature as their degree of freedom in this case, and enable the effects of one dimensional fluid flow. This means we have a reduced order model for capturing heat transfer due to a fluid moving through some kind of cavity without having to explicitly model that cavity. The pipe ‘path’ is specified using a line body.
The line body gets defined with a cross section in CAD, and is tagged as a named selection in Mechanical. This thermal pipe can then interact on appropriate surfaces in your model via a convection load. Once the convection load is applied on appropriate surfaces in your model, the Fluid Flow option can then be set to Yes, and the line body is specified as the appropriate named selection. Appropriate BC’s need to be applied to the line body, such as temperature constraints and mass flow rate, as shown in figure 5.
Figure 5 – Thermal “Pipe” Line Body at Top, Showing Applied Boundary Conditions
This new option under Analysis Settings > Solver Controls allows you to potentially continue an analysis that has stopped due to pivoting issues, meaning a model that’s not fully constrained or one that is having trouble due to contact pairs not being fully in contact.
The options are Program Controlled, Warning, Error, and Off. The Warning setting is the one to use if you want the solver to continue after any pivoting issues have occurred. The Error setting means that the solver will stop if pivoting issues occur. The Off setting results in no pivot checking to occur, while Program Controlled, which is the default, means that the solver will decide.
Figure 6 – Solver Pivot Checking Controls Under Analysis Settings
This new feature allows you to more closely track contact status data while the solution is running, or after it has completed. This capability uses the .cnd file that is created during the solution in the solver directory. It is useful because it gives you more information on the behavior of your contact regions during solution so you can have more confidence that things are progressing well or potentially stop the solution and take corrective action if they are not. The tracker objects get inserted under the Solution Information branch, as shown in figure 7. A.
Figure 7. A. – Contact Trackers Inserted Under Solution Information
A large variety of quantities can be selected to track, such as Number Contacting, Number Sticking, Gap, Penetration, etc.
Figure 7. B. – Contact Results Tracker Settings in the Details View
Contact results tracker quantities can be viewed in real time during the solution, as shown in figure 7. C.
Figure 7. C. – Contact Results Tracker Showing Gap Decreasing as the Solution Progresses
For large assemblies or other complex models, there are useful enhancements in how the tree can be filtered, including the ability to create Groups. Groups can consist of tree entities that are geometry, coordinate systems, connection features, boundary conditions, or even results. Grouping is accomplished as easily as selecting the desired items in the tree, then right clicking to specify Group, as shown in Figure 8. A.
Figure 8. A. – Grouping Displacements
A new folder in the tree is then created which can be named something useful. Figure 8. B. shows the displacement boundary condition group (folder) after it was given a name.
Figure 8. B. – Group of Displacement BC’s, Given a Meaningful Name
It’s easy to right click and Ungroup if needed, and there is also a Group Similar Objects option which allows you to select just one item in the tree and easily group all similar items by right clicking.
In addition to the information on remeshing that we mentioned back in useful new feature number 4, there is a new capability to right click in the tabular listing of results and then right click to create total deformation or equivalent stress results. This capability can make it faster to create a deformation or stress plot for a particular time point or result set of interest.
The procedure to do this is:
The result of these steps will be a new result item in the tree, waiting for you to evaluate so you can see the new results plot.
Figure 9 – Right Click in Solution Tabular Data to Create Deformation or Equivalent Stress Result Items
We’ve saved a fun one for last, the new Explode View capability. This allows you to incrementally ‘explode’ the view of your assemblies, making it potentially easier to visualize the parts and interaction between parts that make up the assembly. To use this feature, make sure the Explode View Options toolbar is turned on in your View settings. There are several options for the ‘explosion center’, such as the assembly center or the global or a user defined coordinate system.
Figure 10. A. – The Explode View Options Toolbar
As you can see in figure 10. A., there is a slider that allows you to control the ‘level’ of view explosion. Keep in mind this is just a visual tool and does nothing to the coordinates of the parts in your assemblies.
Figures 10. B. and 10. C. show various slider settings for the exploded view of an assembly.
Figure 10. B. – Explode View Level 3
Figure 10. C. – Explode View Level 4
This concludes our tour of 10 useful new features in ANSYS Mechanical 16.0. We hope you find this information helps you get your ANSYS Mechanical simulations completed more efficiently. There are lots and lots of other new features that we didn’t mention here. The Release Notes in the Help covers a lot of them. We’ll be writing more about some of the things we mentioned here as well as some of the other new features soon.
If you've been following The Focus for a long time, you may recall my prior article about submodeling using ANSYS Mechanical APDL, which was a 'sub' model of a submarine. The article, from 2006, begins on page 2 at this link:
Also, Eric Miller here at PADT wrote a Focus blog entry on the new-at-14.5 submodeling capability in ANSYS Workbench Mechanical.
Since both of those articles were about structural submodeling, I decided it was time we published a blog entry on how to perform submodeling in ANSYS Mechanical for thermal simulations.
Submodeling is a technique whereby we can obtain more accurate results in a small, detailed portion of a large model without having to build an incredibly refined and detailed finite element model of our complete system. In short, we map boundary conditions onto a 'chunk' of interest that is a subset of our full model so that we can solve that 'chunk' in more detail. Typically we mesh the 'chunk' with a much finer mesh than was used in the original model, and sometimes we add more detail such as geometric features that didn't exist in the original model like fillets.
The ANSYS Workbench Project Schematic for a thermal solution involving submodeling looks like this:
Figure 1 – Thermal Submodeling Project Schematic
Note that in the project schematic, the links are automatically established when we setup the submodel after completing the analysis on the coarse model as we shall see below.
First, here is the geometry of the coarse model. It's a simple set of cooling fins. In this idealized model, no fillets have been modeled between the fins and the block.
Figure 2 – Coarse Model Geometry, Idealized without Fillets
The boundary conditions consisted of a heat flux due to a thermal source on the base face and convection to ambient air on the cooling fin surfaces. The heat flux was setup to vary over the course of 3 load steps as follows:
Load Step Heat Flux (BTU/s*in^2)
Thus, the maximum heat going into the system occurs in load step 2, corresponding to 'time' 2.0 in this steady state analysis.
Figure 3 – Coarse Model Boundary Conditions – Heat Flux and Convection
The coarse model is meshed with relatively large elements in this case. The mesh refinement for a production model should be sufficient to adequately capture the fields of interest in the locations of interest. After solving, the temperature results show a max temperature at the base where the heat flux is applied, transitioning to the minimum temperature on the cooling fins where convection is removing heat.
Figure 4 – Coarse Model Mesh and Temperature Results for Load Step 2
Our task now is to calculate the temperature in one of these fins with more accuracy. We will use a finer mesh and also add fillets between the fin and base. For this example, I isolated one fin in ANSYS DesignModeler, did some slicing, and added a fillet on either side of the base of the fin of interest.
Figure 5 – Fine Model (Submodel) Isolated Fin Geometry and Mesh, Including Fillets at Base
ANSYS requires that the submodel lie in the exact geometric position as it would in the coarse model, so it's a good idea to overlay our fine model geometry onto the coarse model to verify the positioning.
Figure 6 – Submodel and Coarse Model Overlaid
Figure 7 – Submodel and Coarse Model Overlaid, Showing Addition of Fillet
The next step is to insert the submodel geometry as a stand-alone geometry block in the Project Schematic which already contains the coarse model, as shown in figure 8. A new Steady-State Thermal analysis is then dragged and dropped onto the geometry block containing the submodel geometry.
Figure 8 – Submodel Geometry Added to Project Schematic, New Steady-State Thermal System Dragged and Dropped onto Submodel Geometry
Next, we drag and drop the Engineering Data cell from the coarse model to the Engineering Data cell in the submodel block. This will establish a link so that the material properties will be shared.
Figure 9 – Drag and Drop Engineering Data from Coarse Model to Submodel
The final needed link is established by dragging and dropping the Solution cell from the coarse model onto the Setup cell in the submodel. This step causes ANSYS to recognize that we are performing submodeling, and in fact this will cause a Submodeling branch to appear in the outline tree in the Mechanical window for the submodel.
Figure 10 – Solution Cell Dragged and Dropped from Coarse Model to Submodel Setup Cell
After opening the Mechanical editor for the submodel block, we can see that the Submodeling branch has automatically been added to the tree.
Figure 11 – Submodeling Branch Automatically Added to Outline Tree
After meshing the submodel I specified that all three load steps should have their temperature data mapped to the submodel from the coarse model. This was done in the Details view for the Imported Temperature branch, by setting Source Time to All.
Figure 12 – Set Imported Temperature Source Time to All to Ensure All Loads Steps Are Mapped
Next I selected the four faces that make up the cut boundaries in the submodel and applied those to the geometry selection for Imported Temperature.
Figure 13 – Cut Boundary Faces Selected for Imported Temperature
As mentioned above, the Imported Temperature details were set to read in all load steps by setting Source Time to All. The Imported Temperature branch can now be right-clicked and the resulting imported temperatures viewed. I also inserted a Validation branch which we will look at after solving.
Figure 14 – Setting Source Time to All, Viewing Imported Temperature on Submodel
Any other loads that need to be applied to the submodel are added as well. For this model, it's convection on the large faces of the fin that are exposed to ambient air.
Figure 15 – Submodel Convection Load on Fin Exposed Faces
Since there are three load steps in the coarse model and we told ANSYS to map results from all time points, I set the number of steps to three in Analysis Settings, then solved the submodel. Results are available for all three load steps.
Figure 16 – Submodel Temperature Results for Step 2 (Highest Heat Flux Value in Coarse Model)
Regarding the Validation item under the Imported Temperature branch, this is probably best added after the solution is done. In my case I had to clear it and recalculate it. Validation can display either an absolute or relative (percent difference) plot on the nodes at which loads were imported. Figure 17 shows the relative difference plot, which maxes out at about 6%. The validation information as well as mapping techniques are described in the ANSYS Help.
Figure 17 – Submodel Imported Temperature Validation Plot – Percent Difference on Mapped Nodes
Looking at the coarse model and submodel results side by side, we see good agreement in the calculated temperatures. The temperature in the fillets shows a nice, smooth gradient.
Figure 18 – Coarse and Submodel Temperature Results Showing Good Agreement
Hopefully this explanation will be helpful to you if you have a need to perform submodeling in a thermal simulation in ANSYS. There is a Thermal Submodeling Workflow section in the ANSYS 15.0 Help in the Mechanical User's Guide that you may find helpful as well.
A lot of laptops these days come with “switchable” graphics. The idea is that you have a lower capability but also lower power consuming ‘basic’ graphics device in addition to a higher performing but higher power demand graphics device. By only using the higher performance graphics device when it’s needed, you can maximize the use time of a battery charge.
A lot of the ANSYS graphics-intensive applications may need the higher end graphics device to display and run correctly. In this article, we’ll focus on the AMD Firepro as the “higher end” graphics, with Intel HD graphics as the “lower end”. We will show you how to switch to the AMD card to get around problems or errors in displaying ANSYS user interface windows.
The first step is to identify the small red dot graphics icon at the lower right in the task bar:
Figure 1 – AMD Catalyst Icon
Next, right click on the icon to bring up the AMD Catalyst Control Center, if you don’t see the switchable option as shown two images down.
Figure 2 – AMD Catalyst Control Center Right Click Menu Pick
Right click on the same icon again, if needed to select “Configure Switchable Graphics,” as shown here:
Figure 3 – Select “Configure Switchable Graphics” via Right Click on the Same Icon
In the resulting AMD Catalyst Control Center window, click on the Add Application button.
Figure 4 – AMD Catalyst Control Center Window
Next browse to the application that needs the higher end graphics capability. This might take a little trial and error if you don’t know the exact application. Here we select ANSYS CFD-Post and click Open.
Figure 5 – Selecting appropriate executable for switchable graphics
Finally, select the High Performance option from the dropdown for your chosen executable, then click the Apply button.
This should get your graphics working properly. Again, the reason we have the two graphics choices is to allow us to better control power consumption based on the level of graphics that are needed per application. Hopefully this article helps you to choose the proper graphics settings so that your ANSYS tools behave nicely on your laptop.
There are other steps that could be added such as optimization and field verification, but in simple terms those steps outline the product development process. We do this very often at PADT, helping a wide variety of customers develop products to meet needs in the marketplace. Most of the time, we can’t share the work we do publicly, for obvious reasons involving customer confidentiality.
So, when we can share, it’s a good opportunity to show what our tools can do, as well as how we can utilize these tools to help our customers with the steps listed above. We’ll look at a simple example, knowing that the same tools can help with much more complex problems.
In my case, I was faced with a problem. We recently had our back yard pool deck resurfaced. The problem at hand was the contractors accidently lost a plastic lid that covered a 5.5 in. hold on the deck of the pool. This hole was for something like a basketball hoop that could be dropped into this trumpet shaped hole. Figure 1 shows the work in progress, when the original lid was still in place.
After the cleanup was done, that lid was nowhere to be found. You would think it would be simple to find a replacement, especially in metro Phoenix where pool supply stores are abundant. However, after visiting several supply stores as well as scouring the internet, we could not find a replacement 5.5 in. lid. All the available lids were too big and would not work in covering this hole. The hole without a lid is a safety concern. In fact, our 4 year old niece managed drop a foot into the hole and ended up with a scrape. Fortunately it wasn’t any worse than that.
Unable to find a suitable lid for purchase, I decided to pursue a 3D printed solution here at PADT. As I’m sure you are aware, 3D printing has been portrayed all over the media in the last couple of years. For us here at PADT, though, it has been a significant component of our business since the company’s founding in 1994. Knowing that I could have this part printed in plastic here at PADT, I decided to go through the product development process as listed above.
So, let’s look at the various steps I followed in our product development process:
In this case, it was simple. We had a hole in the pool deck that was a safety issue. No replacement part could be found. A new lid was needed, one that would fit properly but also could support the weight of someone walking over it. I decided to design a replacement part that could be 3D printed by one of the rapid prototyping technologies we have available here at PADT.
Besides providing 3D printing services and selling 3D printers, we at PADT are a Channel Partner for ANSYS engineering simulation tools here in the Southwest. I leveraged ANSYS, Inc.’s latest acquisition, the SpaceClaim Direct Modeler as my design tool. SpaceClaim has been available as part of the ANSYS software suite for several years, but now SpaceClaim is officially part of the ANSYS corporate umbrella. SpaceClaim runs within the ANSYS Workbench platform, like the ‘older’ ANSYS geometry tool, DesignModeler. A main different between the two geometry toolsets is that DesignModeler is a history-based modeler, meaning it has a history tree that is followed to create and modify the geometry as we go along. This works well in many circumstances but it lacks the ability to quickly and easily modify existing geometry. SpaceClaim, on the other hand, is a direct modeler in the sense that we work on the geometry interactively, allowing us to rapidly modify geometry by ‘pulling’ on surfaces to grow, shrink, fillet, etc. SpaceClaim is incredibly fast once we get familiar with it.
Knowing that the diameter of the hole was 5.5 inches as measured by a ruler, along with a memory of what the prior cover looked like, I turned to ANSYS SpaceClaim to come up with the geometry model. I sketched a 2D axisymmetric cross section and swept that 360 degrees about an axis to come up with the solid model. I very easily moved the 5.5 in diameter face inward by a small amount to allow for some clearance between the plastic part and the hole into which it needs to fit. The geometry definition literally took just a few minutes, even though I am not yet an expert in SpaceClaim.
I mentioned optimization as a step that could be followed. In this simple case, I didn’t do any optimization but did perform verification that my design would meet an acceptability requirement. I wanted to make sure that my plastic lid could support the weight of an adult standing on it. The tool I used to perform this verification was the ANSYS Mechanical software tool. Like SpaceClaim can, ANSYS Mechanical runs within the ANSYS Workbench environment, meaning that the geometry and subsequent stress and deflection analyses are linked. This allows any needed changes to the geometry to quickly and easily pass from the geometry tool to the stress/deflection model, often with as little as one click of the mouse.
Getting the geometry into the Mechanical model for a finite element simulation was therefore quite simple. Defining loads and constraints on my system was also quite simple. What remained was to define material properties to characterize the plastic being used. PADT’s Rapid Prototyping team informed me that the material to be used is one called Veroclear. This material is used in one of PADT’s 3D printers, called an Objet from Statasys.
Basic material properties for Veroclear are available on the internet, including Young’s Modulus and Yield Strength. Poisson’s Ratio was not available so it was assumed to be 0.3. These properties were entered into ANSYS Workbench. For those not familiar, Young’s Modulus is a quantification of the stiffness of a material. The Yield Strength is a measure of the how much stress a material can experience before permanent deformation occurs. Stress, simply put, is the amount of force being carried per area in a structure. Poisson’s Ratio relates how much a material squishes in one direction when it’s pulled in another dimension.
The loading consisted of a 210 lb. downward load on a portion of the upper surface, representing someone standing on the middle of the lid. The constraints were frictionless supports on the outer cylindrical face as well as the bottom lip. These constraints simulate where these two surfaces touch the hard surface of the pool deck.
Once the model was fully setup in ANSYS Mechanical, the solution was obtained. Lots of matrix algebra behind the scenes takes care of solving the equations needed to obtain the solution. The resulting deflections and stresses looked to be acceptable. I also calculated a factor of safety, relating the calculated stress in the model to the Yield Strength as described above. A factor of safety of 2, for example, means that the predicted stress in the model is half of the Yield Strength. The calculated factor of safety for the plastic lid is 3.17.
From these results we can conclude that, for the loading condition we considered:
Note that this is a simplistic look at the feasibility of our design. We didn’t consider what happens to the plastic in the hot sun, what happens if something heavy falls on the lid, etc. Many other factors could be considered, but in this case I chose to keep it simple.
The part was printed over a weekend in an Objet printer here at PADT. The geometry was saved as a Parasolid file in ANSYS SpaceClaim, and the Parasolid file was then provided to PADT’s Rapid Prototyping team, via the firstname.lastname@example.org email. While the cost of making this particular plastic part using 3D printing is likely too high for a production run, the technology is perfect for making test articles, prototypes, molds, etc.
In this case I only needed one lid, so I took care to make sure that the geometry was accurate before the CAD definition was sent to the 3D printer. The proof is always in the pudding, so to speak, so it was a great comfort to see that the new plastic lid fit perfectly in the hole in the pool deck. If this were a production part, we would probably need a vendor to mold the plastic lids in large batches to make them cost effective.
So, we ended up with a part the met the need, each step done very quickly using the appropriate tools in conjunction with the knowledge of how to use them. We hope you have enjoyed this tour of the product design process, for this simple example. Please keep PADT in mind for your product development needs.