Disable Contact by Subcase

[Ben_defresart]

Using a Nonlinear Static Analysis, I want to run a simulation using two subcases:

Subcase 1 - "tighten" the bolt using an enforced motion displacement.

Subcase 2 - "lock" displacement between the bolt and the base via a bonded contact, then apply load to the cylindrical body.

It seems I cannot enable and disable contacts between subcases?  Can anyone think of a workaround to accomplish what I'm trying to do?

Inventor Nastran 2026

[markus_schulten]

You could try to use orthotropic coefficents for thermal expansion and cool down your bolt in the first step (alpha1/2=0 for radial expansion , alpha3=xxxx for longitutional expansion) - alpha3 is only for the direction of the bolt axis. Iterativly you have to check which temperature is needed with the reaction force in the contacts.

Or you could model the shaft of your bolt as beam-element and add pre-tension in a common way with inventor nastran. The ending points of the beam must be connected to the solid-elemts-head and plate-hole with rigid connectors RBE2 to transfer the moments and forces correctly.

If your model and force distribution is symmetric, you should use this for reducing the computational costs and it is easier for the solver.