Studies in Lubrication: X. Friction Phenomena and the Stick-Slip Process

Studies have been made of the stick-slip behavior recently investigated by Bowden and collaborators. The friction apparatus consists essentially of a table which can be made to rotate at a very low velocity and a slider elastically supported at the center of rotation of the moving surface. Examples are shown of the stick-slip process with several combinations of metals at various speeds and loads. Motion pictures of the slider and table have been made in order to study possible slipping during the stick phase. Temperature records of the stick-slip cycle indicate that the temperature flash is confined exclusively to the slip period and in no case studied exceeds 50°C above ambient. Traces made of the slip phase with very high camera speeds permit an analysis of the variation of kinetic friction with velocity. Thus both static and kinetic friction data can be obtained from a single stick-slip cycle.