The rolling of a ball subjected to normal and tangential loads

Abstract

An elastic element rolling along an elastic track under the action of normal and tangential forces is found to roll a distance which is different from that which would be predicted by a rigid body analysis. This discrepancy may be explained by assuming regions of sticking and microslip in the contact zone, such regions being accommodated by the elastic properties of the system. Experiments are described in which the geometric creep of a steel ball, subjected to normal and tangential loads, was determined for a wide range of load combinations. These results show reasonable agreement with theoretical predictions for the shape of the stick and microslip areas. The correlation of theory and experiment necessitates a coefficient of sliding friction which is markedly less than that obtained for these surfaces in macroscopic sliding tests.