Surface roughness influence in micromechanical fatigue lifetime prediction with crystal plasticity models for steel

Abstract

Although surface roughness significantly influences fatigue, most micromechanical models using crystal plasticity only consider bulk behavior. In this work, a framework is described to include surface roughness in crystal plasticity simulations with emphasis on enabling extensive computational studies. This is achieved by the utilization of a statistical surface roughness generator and the prescription of appropriate boundary conditions. Fatigue lifetimes of a high-strength steel are evaluated for three surface conditions, with the models appropriately parameterized by surface measurements. It is shown that fatigue lifetime prediction considering surface roughness is qualitatively in agreement with experimental observations regarding their mean values and scatter.