How to Parameterize Everything in ANSYS

kaan-80x80One of the best ways to get value out of your simulation is to do parametric analysis. With very little marginal work a completed model can be parameterized to simulate scenarios limited only by your computational time and resources (have you considered a Parametric Pack for parallel design solves?). With ANSYS R18’s promise of digital exploration, DesignXplorer is now included with all CFD, Mechanical and Multiphysics bundles. Sophisticated parametric exploration, optimization and robustness is now at your fingertips. While ANSYS Workbench and DesignXplorer manage your parameters in a consistent interface, setting up a parameter is different in each of the software tools and not always obvious. This document is intended to be a quick reference of how to do so, letting you get over this initial hurdle to take full advantage of the promise of Digital Exploration.

Table of Contents (for quick jumping around):


SpaceClaim Direct Modeler

SpaceClaim let’s you create a parameter from almost any operation:

Param - SpaceClaim Simple

Your parameters show up in the Groups tab.

For more advanced driving dimensions you need to have a dimension on an annotation plane:

Param - SpaceClaim Advanced



DesignModeler has the familiar checkbox to “promote” parameters out to Workbench:

Param - DesignModelerYou can create relations between promoted parameters and other dimensions in the model with the Parameters Pane.

CAD Systems

With the appropriate associative interface licensed and configured, you can make Workbench aware of CAD parameters.

Param - CADBe sure to either use the DS or ANS prefix or else ANSYS will ignore your parameter. You can modify this with the Parameter Key property shown above.


In Mechanical, anywhere you see the checkbox can be promoted to a parameter for Workbench to use:

Param - MechanicalMechanical Command Snippets

APDL command snippets used in Mechanical can also be parameterized, both as input parameters:

Param - Mechanical APDL In

and output parameters (any variable with the Output Search Prefix will be retrieved):

Param - Mechanical APDL OutBe aware that APDL command snippets are not units aware!

Mechanical APDL (ANSYS Classic)

You can also easily use script files from the older user interface in Workbench, easily. With the Mechanical APDL component, specify the input file (along with supporting files as a reference file) and it will be parsed for all of it’s variables. All that’s left is to specify what’s an output and what’s an input:

Param - MAPDL


In Fluent, most places that you can enter a value will have a dropdown that allows you to specify a parameter instead:

Param - Fluent


In CFX-Pre you can specify expressions as parameters and use them as inputs in other parts of the model:

Param - CFX


In CFD-Post you base parameters off of expressions as well, making sure to use the nice right click menu to help with building expressions:

Param - CFD-Post

Maxwell & HFSS

The user interface is similar enough in these tools so that the same instructions apply. When accessing these from Workbench, a DesignXplorer node is created under the Optimetrics portion of the tree. Optimetrics is an EMAG specific optimization tool that is complimentary to DesignXplorer. In most places in Maxwell and HFSS, enter an identifier instead of a number to automatically create a parameter. Promote it out to Workbench in the DesignXplorer node. In the DesignXplorer node, output variables can be created in the Calculate tab.

Param - Maxwell HFSS


Similar to the above, in the user interface where you would normally enter a number, instead enter an identifier preceded by $. Then in the Define Trials dialog, expose the parameter to Workbench.

Param - Icepak

And that’s it! Remember that the power of an integrating platform like Workbench allows you to have several of these software tools be connected in the same analysis flow. From CAD Parameter interaction to coupled field analysis, it’s all possible. Now go forth and digitally explore your design space!

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ANSYS Hardware Requirements Update 2017

kaan-80x80Thinking about buying some new simulation hardware? Make sure to check out our updated ANSYS Hardware Requirements page to read about the many factors that affect simulation performance, including our recommendations on how to get the most out of your hardware investment. Notable updates to returning readers include the importance of keep it in memory and more detail on storage recommendations. I’ll also highlight a few interesting developments on the hardware horizon.

Importance of Storage

With Solid State Drives (SSDs) becoming cheaper and RAID0 arrays of SSDs becoming feasible due to TRIM support, SSDs are starting to go from a luxury to a baseline for new simulation hardware. If you are commonly performing one of the following types of I/O bound analysis:

  • Out of core Sparse Solver in Mechanical
  • Block Lanczos Eigensolver
  • Distributed Memory Parallel (DMP) solves (in SMP, there is one set of files, in DMP each core has its own set of files and IO becomes a bottleneck)
  • Transient FEA or CFD runs where many results are being written to disk

…then you will see fantastic speedup from increasing storage performance. ANSYS R18 Mechanical allows you to specify a custom project scratch directory so you can automatically take advantage of specialized high performance solve drives.

The top of the line storage solution is a RAID0 array of SSDs. Make sure that your SSD/OS supports TRIM on RAID0 arrays specifically, like on this page, or you will see decreasing write performance over time.

Read more in the Updated Storage Section

Even Better than Storage: Memory

Improving storage performance is well and good but many times the best performance is to use the disk (Mechanical or SSD) as little as possible. For some types of analysis using the disk is unavoidable but what you really want to avoid is not having enough memory so that the CPU uses the disk in place of memory. The disk is the slowest type of memory, with the system memory (RAM) being faster and the on-CPU cache (different levels of which are called L1/L2/etc…) being the fastest you can get. To compare the relative speeds of these memory levels we can use the metaphor from this article:

  • L1 Cache: Grabbing a piece of paper from your desk (3 seconds)
  • L2 Cache: Picking up a book from a nearby shelf (12 seconds)
  • System Memory: Taking a walk down the hall to buy a Twix Bar (4 minutes)
  • Accessing the Hard Drive: Leaving the building and roaming the earth for 1 year and 3 months

While the CPU is accessing these various memory levels it is sitting idle. The difference between those last two levels is why you should always get as much as memory as possible!

Read more in the Updated Memory Section

Don’t Forget to Upgrade Your Software Too!

Another way to get the most out of your hardware is to keep up with current versions of ANSYS. Every new release there are improvements in solve time, pre and post processing time and ease of use. In addition to these there are some improvements to HPC licensing as well with the latest release:

  • 4 cores with the new Fluids Packaging: In addition to giving you DesignXplorer/Fluent/CFX, all levels of the new CFD Package come with 4 cores to get you started on running your simulations in parallel
  • 1 HPC Pack = 10 cores: Those first cores that you parallelize will often have the greatest effect on your simulation time. With the new HPC Pack licensing, you get 10 cores off the bat.

Some Interesting New Developments

AMD has come back in force with their new Ryzen CPUs. They are especially good for multi-threaded applications so there is definite application to ANSYS:

Virtual Reality!

What’s happening in this mysterious picture, taken at the SVEC Banquet earlier this year?


Contact us to schedule a visit to find out!

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Register to Attend the ANSYS R18 Webinar on 1/31


Taming Product Complexity with Pervasive Engineering Simulation

Manufacturing is undergoing the most fundamental transformation since the introduction of the assembly line. Trends like the Internet of Things, additive manufacturing and machine learning are merging the physical and digital worlds, resulting in products that defy imagination. But this new opportunity brings considerable complexity — complexity that can be tamed with pervasive engineering simulation. Pervasive simulation expands simulation’s traditional boundaries, broadening the use of these tools upstream to product design and downstream to operations through the use of digital twins.

Join the new CEO of ANSYS, Ajei Gopal, and visionary customers Cummins, Nebia, Oticon, Metso, GE Digital as they demonstrate the power of pervasive simulation. You’ll also hear directly from the ANSYS development teams that have worked tirelessly to produce the latest version of our industry-leading solutions. They’ll discuss how ANSYS 18 deepens and strengthens the ANSYS engineering simulation platform — and how it supports new applications.

Attend this webinar to learn:

  • How you can use digital exploration to quickly evaluate changes in design, reducing development costs and preventing late-stage design changes
  • How digital prototyping enables you to provide insights into real-world product performance, test “what-if” scenarios and ensure optimal designs
  • How simulation is moving downstream of the product lifecycle through the use of digital twins to increase efficiency and to decrease unplanned downtime
Register to attend this interactive webinar on the future of pervasive engineering simulation

January 31, 2017
8:00AM – 10:00AM PST


First Name:

Last Name:

Email Address:


Meet our ANSYS Speakers:
Ajei Gopal Andre Bakker Dale Ostergaard Larry Williams Sergey Polstyanko Eric Bantegnie
Ajei Gopal

President and CEO

Andre Bakker

Senior Director Fluids Development

Dale Ostergaard

Senior Director Software Development

Larry Williams

Senior Director Electronics Products

Sergey Polstyanko

Senior Director, Research and Development

Eric Bantegnie

Vice President and GM, Systems Business Unit

Are Cats a Fluid? Thinking (and Learning) about CFD Through Humor

kaan-80x80The internet has uncovered some intriguing evidence on the rheological state of a common household item. How do physical constants like Deborah’s number, adhesion, relaxation time and catpillary number apply in unusual situations? I came upon this topic from the Improbable Research Podcast and the pictures are from the linked rheology bulletin. Welcome to the internet and read on to learn some CFD terminology as applied to an interesting and ridiculous question.

reheology-of-cats1Deborah Number: Given enough time, everything flows. The ratio of relaxation time to the time of observation can be used to determine if something behaves as a gas, liquid or solid in your timescales of interest. Do older cats have a higher relaxation time? Is the question of whether cats flow reminiscent of the wave-particle duality of light? If so, is it of equal to or greater import?

Solid-Liquid-Gas Continuum: Solids that deform under stress vs liquids that flow to fill a container. Clearly the full spectrum can be observed in certain specimens.

Capillary Bridge: Observed in extensional rheometry experiments of test samples (see 2a). The subject is suspended between arbitrary rigid body surfaces. It remains to be seen how important surface tension and transient strain-hardening are to these CATBER (Capillary thinning and breakup extensional rheometer) experiments and other awesome words.


Lotus Effect: The substrate pictured in 2c seems to exhibit extreme felidaphobicity, showing high contact angles on the outer surface. Suggests possible applications in the tops of tables and desks.

Yield Stress: The ketchup in a bottle effect is observed (2c) due to the cat being below its yield stress. This is distinct from the free surface flow effects observed above.

reheology-of-cats3Reynolds-Weissenberg Number: The ratio of the relaxation time vs the rate of deformation. As this number increases, secondary chaotic flows emerge. For simple, non-viscous fluids this is Turbulence and depends primarily on inertia. For biologically active materials, their rates of deformation can be dependent on its environment.

Don’t forget that you can always perform your own experiments in silico, without harming any cats, using ANSYS Fluent. In the material properties of a fluid you have a variety of viscosity and turbulence models to simulate all of the non-Newtonian felines that you desire. Happy new year!

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