Computational service life estimation of contacting mechanical elements in regard to pitting

Abstract

A computational model for determining the service life of contacting surfaces in regard to surface pitting is presented. The model considers the material fatigue process leading to pitting, i.e. the conditions required for the short fatigue crack propagation originating from the initial crack in a single material grain. In view of small crack lengths observed in surface pitting, the simulation takes into account the short crack growth theory. The stress field in the contact area and the required functional relationship between the stress intensity factor and the crack length are determined by the finite element method. An equivalent model of two contacting cylinders is used for numerical simulations of crack propagation in the contact area. On the basis of numerical results, and with consideration of some particular material parameters, the probable service life period of contacting surfaces is estimated for surface curvatures and loadings that are most commonly encountered in engineering practice.