Numerical Study on Subsurface Stress in Hertzian Contacts under Pure Sliding Conditions

In this study, the two-dimensional numerical simulation on the subsurface stress field in Hertzian contact under the pure sliding condition for different speeds and coefficients of friction is presented. The Hertzian contacts are represented by a dry contact between a rigid flat surface and an elastic cylinder with radius R=12.5 mm. Simulation is carried out through two steps, the first one is for applying normal load and the second one is for applying angular speed for the cylinder. The results of subsurface stress filed for pure sliding are compared to non-moving Hertzian contact. The results show that pure sliding speed has a major effect on the value of maximum von Mises stress in the subsurface of contact. The effect of sliding speed is attributed to tangential forces and elastic deformation in the contact. On the other hand, the coefficient of friction has a primary effect on the position of maximum stress and the shift of the contact region. Indeed, when pure sliding motion is introduced with a low value of friction coefficient, the shift of the contact region is negligible compared to non-moving Hertzian contact. The study is extended to investigate the effect of contact geometry on subsurface stress for Hertzian contact in the cam-follower interface. The shape of the follower has a significant effect on the value and distribution of Hertzian stress, thus, the fatigue life of rubbing surfaces of the cam-follower interface.