Dry Friction between Soft Rough and Hard Smooth Surfaces

Abstract

The frictional behavior under unlubricated condition was investigated, which is affected by the surface conditions such as surface films, adhesion and wear. When the surface films on the contact asperities were ruptured during sliding, the real area of metallic contact generally grew as sliding proceeded. There was a simultaneous growth in the friction force resisting sliding. Two frictional experiments have been carried out to examine the mechanism of the friction. One consisted of measuring the friction force at a single point of contact for sliding of a soft slider on a hard flat surface. This assured understanding of the behaviors of the breakdown of films and the junction growth. The other comprised the measurements of friction force at the multiple points of contact between a soft rough and a hard smooth surface. The friction force was also deduced theoretically in both cases of the single and multiple points of contact.