Three-dimensional finite element analysis of surface deformation and stresses in an elastic-plastic layered medium subjected to indentation and sliding contact loading

Three-dimensional finite element simulations of the indentation and sliding of a rigid sphere on a half-space with a harder and stiffer layer are presented. The sphere is modeled by contact elements, thereby avoiding a priori assumptions for the pressure profile. indentations are performed to normal loads of 100 and 200 times the initial yield load of the substrate material and subsequent sliding is performed at a constant normal load to distances of approximately twice the indentation contact radius. Two complete load cycles are performed in selected cases to assess the effect of repeated sliding on the surface displacements and contact stresses. The effects of layer material properties, interface friction, and normal load on the sliding and residual contact stresses and forward plastic flow are examined. Emphasis is given to the sliding and residual tensile stresses at the surface in order to assess the consequences for crack initiation and subsequent failure as a function of the layer material properties, the coefficient of friction, and normal load. The finite element results are shown to be in good agreement with the results of analytical and experimental studies.