Author(s)

S. D. Lee, H. J. Chu, Y. J. Cho, H. S Park & H. J. Kim

Abstract

An analytical model to calculate the contact fatigue life of rough surfaces is presented in this paper. The effect of surface roughness can be calculated using this model. The computational method and the theoretical basis are also discussed. Contact stresses are obtained by contact analysis of a semi-infinite solid based on the use of influence functions; the subsurface stress field is obtained using rectangular patch solutions. A mesoscopic multiaxial fatigue criterion which can yield satisfactory results for non-proportional loading is then applied to predict fatigue damage. A suitable counting method and damage rule were used to calculate the fatigue life of random loading caused by a rough surface. As a result of the analysis the relationship between the life and the roughness as well as the most probable depth of the crack initiation is calculated. Keywords: contact fatigue, rough surface, life estimation. 1 Introduction Machine elements such as gears and bearings are subjected to non-conformal contact where the two bodies initially make contact at a single point or along a line. Due to the highly concentrated load at a contact area, irreversible degradation of the surface, e.g. pitting, spalling or flaking, can occur after the finite number of cycles. These surface degradations are widely known as contact fatigue.

Keywords

contact fatigue, rough surface, life estimation.