The crack propagation theory under rolling contact

A model to calculate the fatigue life (residual durability) of solids under rolling contact, which is based on the concepts of linear fracture mechanics, has been proposed. The construction of a crack growth path in one of the bodies of a contacting pair, using applicable criteria of local fracture, equations of crack growth rate and characteristics of cyclic crack growth resistance of the material, is a key element of the model. The rolling body is modelled by a half-plane and the contact interaction of the bodies in every rolling cycle is simulated by repeated translation motion of normal and tangential forces along the half-plane edge, which are distributed on the contact area by a certain law. The calculations of the path and stress intensity factors along it are carried out by the step-by-step process on the basis of the singular integral equations method. Edge crack growth paths have been investigated and the residual durability of the rolling surface of 75XITCT steel has been estimated.