RBE3 elements with full rotation coupling seems to give incorrect results

[kmoks]

A hollow beam model (rectangular box profile) is modelled with 4-noded shell elements with RBE3 elements in both ends for boundary conditions and applied load (see attached model SAPPEI-3754.zip . The deformations appears too large when also the rotations are coupled in the RBE3 spiders. If only translations are coupled (which used to be the default in NX before), the response looks more normal. Full rotation coupling in RBE3 is not tested much in Fedem, so we suspect an implementation bug. This should be verified.

This was first reported in the Jira issue EPDQUALITY-70 for Connected Products, and is reproduced here for Open FEDEM.