The determination of coefficient of friction between a cylindrical indenter and a plastically deformed body by caustics

The contact between an elastic cylindrical indenter and a plastically deformed bar is examined. For this study it is assumed that the normal and tangential loads in the contact zone are related by a Coulomb-type relation. In order to determine the coefficient, which relates the normal and tangential loads, the method of reflected caustics was used. For the evaluation of this coefficient a single measurement of an appropriate length has to be made on the caustic, which was formed at the contact area of the two materials. This measurement allows the determination of the coefficient and in the case when the normal distribution of the contact load is known, the tangential load distribution can be readily obtained. The method was applied to the case of an uniformly distributed load, applied to an elastically deformed cylindrical indenter, which deforms the indented bar plastically.