Peter is right. If this is free to move at all (aka unstable) then its going to show strange behavior (i.e. huge rotations as in your picture) for a static analysis. You could try turning on inertia relief. Weak springs can help, but not much. But I really don't understand what problem you are trying to solve. What is the loading on this? Seems you are taking the wrong approach.
You are navigating away from the AIS Discovery experience