Equilibrium Check and Epsilon for model with contact and without contact

Question

Hello I ran two models, one with contact and one without contact.

As part of model checking i check the epsilon value (round off error ). I noticed that the model with contacts does not produces epsilon value.

Can any one explain why is not writing the value?

Also, I noticed that my equilibrium checks are also not coming out to be zero.

Attached are snapshot from equilibrium checks from both models. ​

How can I fix these errors ?

Attached Files (2)

Darrel Sinclair · Accepted Answer

Only the touching contact itself is nonlinear. All other assumptions for linear static analysis still hold: small displacement, linear materials, etc. Touching contact in SOL101 uses the same algorithm as used in SOL400. You can find more information on this in the Nastran documentation: MSC Nastran Nonlinear (SOL400) User's Guide

https://simcompanion.mscsoftware.com/infocenter/index?page=content&id=DOC11516

As long as the mismatch in your equilibrium check is small (as it is here), you should be OK. You've already run the model without contact, so you know it's OK for equilibrium and the differences are purely due to the contact.