AltaSim Technologies is a COMSOL certified consultant, offering consulting, training, and concept development. Essentially, a bunch of smart people who know how to do CAE right.
Every once in a while, AltaSim sends out a tips & tricks email. Here’s one that caught my attention:
Unless you know for sure (like 100% sure) that you won’t need to change any dimensions or geometric features of your model at any time along the way, it is beneficial to take the time up front to Parameterize your geometry. With parameterized geometry, complicated and otherwise time-consuming geometry updates can be made in a matter of seconds. In addition, a COMSOL solver sequence can sweep in parameter space over a geometric parameter.
Time-savings could be your biggest benefit with this tip. Think of how time-consuming it would be to change your model from 3 coils (bends) to 6 coils (bends), for example. But with Parameterized geometry, you are only a few mouse clicks away from updates when dimensions or features change. Depending on the complexity of your problem and the number of changes, this could be hours of time savings. It may be tempting to save time initially by parameterizing only the geometry you anticipate could need changes, but once we start looking at results we find ourselves changing other dimensions as well.
This is an example of something that sounds pretty simple on the surface, but requires a bit of thought to do right.
The first question that occurs to me is which model do you parametrize: The design (CAD) model, or the analysis (CAE) model?
The second question is how do you parameterize it?
In integrated parametric CAD/CAE systems, such as SolidWorks Simulation, the analysis model is a configuration of the design model, with insignificant features turned off. The parameters are already there, and can be used directly for CAE optimization.
COMSOL can certainly be used with CAD model based parameters. But it also supports its own parameterization tools. It’s possible to read in a CAD model (from any source) as a dumb solid, simplify it to create an analysis model, then parameterize that analysis model, in a manner that represents your design intent, and lets you properly optimize the model.
Which way is better? It’s a workflow issue. You do it whichever way is fastest. If you can automatically regenerate the analysis model from the design model, then it makes sense to use the design model’s parameters. If the process of generating the analysis model from the design model is time consuming, and requires manual work, then you should probably parameterize the analysis model.
Blake Courter says
With direct modeling, it is now no longer necessary to put the right parameters in the model when you build it. SpaceClaim, for example, can add parameters post-facto to dumb, imported geometry from any CAD system. CAE tools, including COMSOL, can use those parameters to optimize geometry.
(A SpaceClaim employee)