Choosing Ansys Over CAD-Embedded Simulations

April 7, 2023 Taylor Jeffrey

Right now, you’re using CAD embedded simulation tools. How do you know when it’s time to upgrade?

At Rand Simulation, we hear this statement all the time: “We’ve just been using the embedded simulation since that’s what we use for CAD.”

And we’re the first to admit that those types of tools may be easy to use, a good option for some types of analysis, and cheap. Most of our team have used the standard engineering tools for CAD and/or simulation, so we get where you’re coming from.

Sometimes, it seems easier to keep pushing ahead with CAD embedded simulations even when you’ve run up against these limitations and issues. One of the biggest concerns we hear about using Ansys is that it’s a new software and it would take too long to learn.

Think of it this way: if you’ve never used a chainsaw before, it’s going to look intimidating! And while you could technically cut apart a fallen tree with a handsaw, we all know the chainsaw’s speed and efficiency are going to make up for the time spent learning how to use it.

So, when is it time to upgrade to Ansys?

Ansys tools for simulation may feel daunting, but there comes a point when CAD embedded simulation capabilities aren’t enough for the work you’re doing. When you’re working on large assemblies, nonlinear contacts, advanced materials, dynamics like vibrations and impacts, or multiphysics you may be running into the limits of what CAD embedded simulation can do.

Let’s look at some of the limitations that engineers and analysts frequently run into with CAD embedded simulation:

  • High number of contacts and lag when dealing with large multi-part assemblies
  • Minimal (or nonexistent) multi-physics capability
  • Slow solver speeds and long run-times
  • Questionable accuracy and fidelity due to limitations in mesh size that the software can handle
  • Lack of training and technical support for best practices with simulation
  • Difficulty cleaning up CAD or inability to use multiple types of CAD files

Large Assemblies

Individual parts or small assemblies are straight forward enough to be handled by most CAD embedded simulation, but when you start looking at 100-1000+ parts in an assembly, or non-linear contacts within that assembly, the efficiency of Ansys really shows thanks to key features like

  • Automatic contact detection
  • Fracture, delamination, and disbands
  • Options for setup and post processing designed for large models
  • Wide variety of in-built connections – contacts, springs, beams, mesh connections, welds, and joints

Watch YouTube Video on Large Assemblies

Nonlinear Contacts

The simplest approach for modeling is to use bonded contacts everywhere, but that’s just not accurate in most cases. Whether it’s press fit, sliding frictional contacts, or other nonlinear behaviors, Ansys has powerful algorithms designed for detection, stabilization, and convergence of a wide variety of contact behaviors. Even a complex problem can be solved using the automated and user-friendly controls with very few adjustments. 

Advanced Materials

While there are occasions when a nonlinear material can be effectively approximated by a linear model, that isn’t a viable solution to every problem. When you enter the realm of more advanced materials, you need a more advanced analysis to handle it efficiently and effectively.

If you start working with plastics, you’ll probably be interested in at least a bi-linear model, if not a multilinear model. And if you have rate dependent behavior on something like an isolator, you’ll need to model that viscoelasticity. Ansys can also handle hyperelastic materials like rubbers or elastomers used for seals.

Read Our Modeling Isolators & Springs Blog Post

Other advances materials like SMAs (shape memory alloys) are used to create self-expanding cardiovascular stents. Complex materials can have different stiffnesses, shapes, and behavior depending on temperature and if the material is in tension or compression. Even so, this is well within the capabilities of Ansys.

Dealing with composites? Ansys has composite tools for using existing materials, designing your own, and creating your layup ply by ply. The post processing can even identify which ply is at the most risk of failure.

Watch Video on Composites

Dynamics: Vibrations and Impacts

Whether you are dealing with MIL-STD-810, drop testing, seismic loading, or other vibration and dynamic analyses, Ansys has you covered. With both linear and non-linear capabilities, everything from road transport loading to DDAM to impacts can be simulated and evaluated within Ansys.

Watch Video on Vibrations & Impacts


One of the best features that Ansys has is the ease with which multiphysics can be integrated. One-way FSI, two-way FSI, thermo-structural, electronics and structural, RF-structural, and more. Below is a thermo-structural example from the Ansys Learning YouTube channel which shows the setup and solution of a brake in action.

Watch Thermo-Mechanical Multiphysics Video

And of course, when you upgrade from CAD embedded software to Ansys, you will also have access to technical support directly from our engineering teams. With decades of experience in simulation, we can help troubleshoot technical problems, provide guidance on problem solving, and much more.

Upgrading to Ansys may seem daunting, but we can support you every step of the way. And if you are not ready to run all the simulations in-house, talk with us about a consulting engagement plus knowledge transfer. We will get everything up and running and make sure your team can take the reins by the end of the project.

Connect with the experts at Rand Simulation, today!

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