Inventor Simulation

[sking]

I have noticed that as I increase my tolerance value in CONTACTS in the simulation settings my results will dramatically change.

My initial settings are 0.004" with SEPARATION as default. After completing the automatic constraints, I will manually bond all the necessary components such as nuts to bolts and welds to the plates.

Then if I change 0.004" to 0.5" and leave it as SEPARATION, to pick up clearance holes, etc., the result will resemble the way the assembly should behave.

But if I change the separation to 1.0" (and nothing else) then the simulation will run with results that are not correct, giving large deformations and very high stresses.

Is there anything wrong with what I am doing that may cause this change in the results?

Any help on this matter would be great, thanks.

Steve

[henderh · Accepted solution]

Hi Steve,

  You may be generating spurious automatic contacts if you increase the default contact tolerance too large.

  I think your approach is good, but only increase the default contact tolerance to what is needed.

  To experiment with 'what if' scenarios without disturbing the well-behaved results, you can make a copy of the simulation (RMB on the simulation node in the browser).  Then set the default contact tolerance to the larger value and check if 'spurious' contacts are being generated.  If present, it's likely these are the cause of the unrealistic results.

Hope this helps...

-Hugh