Are screwy CAD models ruining your upfront CFD ROI?

This point bears repeating:
A manufacturing-ready CAD model is not the same as a simulation-ready CAD model.

I often see engineers spending days and weeks trying to dumb down manufacturing-ready CAD models for use in CFD and FEA programs. That is largely a waste of time. The same ultimate results could be had in a fraction of the time by quickly sketching a simplified simulation-ready version of that CAD assembly.

In most cases, you don’t need screws, screw holes, 30 sheet metal parts (which look a lot like 1 continuous sheet metal part when assembled) and other minutia. Just onion skin a new part over multiple complex parts, or just eliminate them altogether if they have no impact on the analysis solution.

It’s humorously difficult to get Engineers to do this the first couple times. Couple of reasons for that:

  1. They spent a lot of time creating that manufacturing-ready CAD masterpiece. “Why should I have to change it? It took me weeks to build this beauty!”
  2. Most Engineers learn CAD through CAD reseller training courses. All of that coursework culminates in the student becoming a Designer who knows how to fully detail CAD models for manufacturing.

Consider point 2 for a moment. There simply are no classes available through CAD resellers that focus on CAD for analysis! Onion-skinning, building a quick & dirty model with simulation in mind, etc… none of that gets taught!

Ask your CFD or FEA vendor if they can customize a class on CAD for Simulation for your team. You’ll be amazed at the effects on simulation throughput.

2 comments

  1. Well said.. I think a common opinion is that the CFD/FEA vendor will come in and “mess up” the system. To me, put them to the test. They should be able to come in and fully adapt to your current process.

    Do you use Design Tables, Configurations, Level of Details, Simplified Reps? If so, then you should be able to adopt the analysis modeling philosophy seamlessly into your process, not create a completely separate foreign process.

  2. Well said.. I think a common opinion is that the CFD/FEA vendor will come in and “mess up” the system. To me, put them to the test. They should be able to come in and fully adapt to your current process.

    Do you use Design Tables, Configurations, Level of Details, Simplified Reps? If so, then you should be able to adopt the analysis modeling philosophy seamlessly into your process, not create a completely separate foreign process.