I am having trouble properly restraining a fairly simple cylindrical vessel with end caps when attempting to simulate the effects of the pressure at 3 km depth in saltwater (4390 psi). I have made all the contacts bonded and added a fixed restrain on the OD of the cylinder after having the study fail for large displacements and still get the large displacement error. Any tips?
Have you tried a global bonded contact?
It is possible that the external pressure is so great that the vessel boundary is deforming that much. Try running with 1 psi external pressure.