A Preliminary Analysis of Subsurface Crack Branching Under a Surface Compressive Load

Abstract

This paper presents the results of a preliminary analysis of the branching behavior of a horizontal subsurface crack subjected to a moving compressive surface load. The purpose of the analysis is to provide some fundamental understanding concerning the behavior of subsurface contact fatigue cracks, including the onset of pitting or delamination. The analysis is approximate inasmuch as the traction-free boundary condition at the surface is only partially satisfied, and the history dependent effects arising from crack face friction are not included. The results show that mode I branching crack growth is possible even though the stress field is largely compressive. Nevertheless, based on a simple competing failure mode model the results indicate that within the limits of the analysis, nonbranching mode II growth is likely to be the dominant mode of propagation.