Multiphysics Pin to Seal Contact with Various Friction Models
The example described demonstrates various friction models of a rigid pin being inserted into and extracted from a rubber seal. The frictionless case, as expected, has the lowest insertion and extraction force whose peak value is around 20 N. Adding friction dramatically increases the peak insertion force to about 95 N, and the extraction force minimum peak is about -135 N. All three friction models produce nearly the same force history as long as the sliding velocity of the Arc Tangent type is properly set. The proper sliding velocity for this case is determined by the velocity of the pin during the insertion which gives a value of 0.020 cm/sec. Note what happens when the default sliding velocity is used, the effectiveness of the friction is dramatically diminished, and is incorrect. Comparing run times of various friction methods, the frictionless case requires the least amount of run time, followed by the Arctangent, then Bilinear, and the Stick-Slip model last. As designed, the Bilinear takes a bit more times but has the benefit of realistic default parameters that do not underestimate the friction forces like the Arctangent friction model. As an alternative, one can perform this analysis with the segment-to-segment friction approach. This method is advantageous in that it does a better job for self-contact that occurs in this model. This is activated using the Jobs Contact Control menu shown below. The resultant contact status is also shown.