I need some clarity about what is happening in the analysis tab of a mate. The friction definition is straight forward but the joint dimensions and how they're applied in motion is confusing. What does it do with these dimensions to compute frictional forces? Most of these seem to be based upon units of area yet I always thought friction was independent of area. Can someone please define the equations for computing friction forces based upon each of the frictional geometry types?
Hi Chad,
you really are right, friction is independent of area, but in joint friction, the joint dimension can affect the way the forces are reacted by the parts, and then the friction forces are also affected.
Imagine a hinge, if you got a bearing force (F), the friction force will be nu*F. But, if the hinge has a little gap, and, you add a torque, the pin will rotate and will touch not along the hinge, but in the external edges. So, the reacted forces will be different, and this ones are hinge length dependent, so, the largest hinge, the different forces you'll have. At last, the area is not important, because the friction is not dependent, but it does the geometry, because the forces will distribute in a different way.
Regards!