I am trying to optimize the design of a Hirth coupling I am working on and would like to try to simulate the design in Solidworks.  There is a Belleville washer (spring) pushing the two parts together.  This seems like a fairly simple exercise: add a spring (or use a force), turn contact bodies on for both parts, and either add a motor and monitor torque or add a torque instead of a motor.  No matter what I try I never get the parts to interact how they should -- the part that's moving will usually fly either partially or all the way through the fixed part, or bounce left and right on the order of inches.

Any tips?