Energy dissipation in a frictional incomplete contact with varying normal load

The problem of a plane incomplete frictional contact, subject to a constant normal force, together with periodically varying tangential and additional normal forces, is studied. The evolution of the stick-slip patterns, together with the frictional energy dissipation, both pointwise and summed over the whole contact, is found for a wide range of load cases, for two example geometries. viz. a Hertzian contact and a contact having a central flat face and rounded edges. The results are useful both in determining the damping properties of the contact and in assessing the localisation of surface damage which may give rise to fretting damage and possible crack nucleation.