A Thermal Elastohydrodynamic Theory for Individual Asperity-Asperity Collisions

Abstract

A thermal elastohydrodynamic theory is developed for the collision between two idealized asperities on surfaces in sliding contact. Numerical solutions are obtained for the pressure, temperature, and film thickness between the asperities as functions of their overlap, the sliding speed, and the time since the initiation of the collision for a given lubricant and asperity geometry. It is shown that extremely high pressures, temperatures, and surface shear stresses are to be expected at the center of the contact region. The tractions generated are shown to be of the same order as the load capacities. At the higher sliding speeds, overlapping asperities may pass over each other, separated at all times by a finite lubricant film. At the lower sliding speeds, boundary processes must take over before the completion of the collision.