When bending is acting on the slip joint, the outputresults show huge contrary restraint-forces on the slip joint nodes.

Is there a possibility to prevent this and is there a possibility to show the rotation occurring in the slip joint?

We assume that the thrust load has to be incorporated?

You can model this "play" in the joint by individually defining gaps on the appropriate restraints. If modelling the slip joint using restraints across a single Node/CNode pair, put a gap angle on the two rotational restraints that are perpendicular to the pipe. If modelling the assembly at two locations along the pipe, then gap the appropriate translational restraints (which form the couples providing the rotational restraints).

It's up to you to determine if the gaps are accurate and the results acceptable.

Thank you very much. You have 'confirmed' our idea about this matter.