Energy Dissipation in Contact Friction: Constant Normal and Cyclic Tangential Loading

When a sphere is held between parallel flat surfaces by means of a constant clamping pressure and is then subjected to a cyclic tangential displacement parallel to the flats, energy is dissipated at the contacts. This occurs even when the maximum tangential force, T*, is less than T_max, the force which will just produce slip over the entire contact surface. Measurements of the energy dissipated per cycle and of the hysteresis loop shapes have been found to agree well with the theory of Mindlin and Deresiewicz in the range investigated, 0.45 < δ*/δ_max < 1. The sphere diameter and the normal load appear as parameters only in the way demanded by the theory. In the range investigated energy dissipation appears to be primarily a surface phenomenon and not one due to material damping. The material employed has been AISI 316 steel.