On the experimental techniques for assessing the specific friction force and its parameters

Abstract

The experimental techniques and conditions for assessing the specific friction force and its parameters are reviewed. The values of the specific friction force and its parameters obtained by various techniques in various ranges of the normal contact pressure are compared. The reasons behind the disagreement of the specific friction force values obtained by various techniques, as well as the conditions of their agreement, are analyzed. It is recommended that the values of the parameters of the specific friction force should be assessed under the conditions of a plastic deformation at high contact pressures not less than a half of the hardness of the softer material of the frictional pair. In the range of low contact pressures, the parameters of the specific friction force should be assessed considering the micro- and nanoroughness and the adhesive interaction between the surfaces.