Multiaxial high cycle fatigue threshold with small defects and cracks

In this study, the effects of small surface defects and small cracks on the fatigue limit of metallic materials were investigated. As a theoretical framework, the McEvily model was adopted to account for the Kitagawa effect, the elastoplastic behavior in the vicinity of the crack tip, and the crack closure development in a unified manner. Based on the comparisons between the theoretical predictions and the experimental data, the predictive capability of the present method was examined by focusing on the influence of defect size and biaxial stress. Finally, in view of the area -parameter model, our effort was devoted to propose a simple yet reasonably accurate equation to predict the fatigue limit.