Learning Forum

[Dennis Chen]

if I artificially scale the mass of an entire component, like every single element on it, and matsum check after solve still show KE is nearly non-existent (like 1% of IE or less), can I make the claim that my result is, for the most part, just as accurate as if I had solved the same problem implicitly in a static structural sense. basically, I am looking for a reason why literally 100x my density value (or selectively mass scale one part by a lot) on my mat card for that one component would invalidate my result in a quasi-static analysis. I can't think of one but can anyone help me think of one?

[Ram Gopisetti]

Hi Dennis, 

• If KE is small, it usually means dynamics aren’t messing with your solution, so you're likely good.

• BUT... scaling mass by 100× can still affect things like:

  • Local dynamic effects (e.g., contacts, fast motions)

  • Stress wave speeds (they drop with higher mass)

  • Inertial mismatch in assemblies

  • Weird behavior if rate-dependent materials or damping are involved

So, as long as you're not seeing weird contact forces, rate effects, or local high KE, and you're just after the final deformed state, you're probably safe. To be sure: compare results with and without the mass scaling, or use selective mass scaling instead of cranking up density.

Cheers, Ram

[Dennis Chen]

Ram, thank you for your response!