Mean stress effect in multiaxial fatigue limit criteria

Abstract

The paper deals with evaluating the mean stress effect in multiaxial criteria for fatigue limit estimation, with special emphasis on the mean shear stress effect. The usual practice of accepting the mean normal stress effect and neglecting the effect of static torsion is scrutinized. Two methodstwo critical plane criteria, PCr (Papuga Criterion) and QCP (Quadratic parameter on the Critical Plane)are described, and additional local stress parameters representing the mean torsion effect are implemented. The efficiency of the new implementations is evaluated on a large data set of 407 fatigue limits. Additionally, outputs of two other well-known methodsthe Crossland method and the Dang Van methodare provided for comparison. The positive outcome of including the mean shear stress effect is evident not only in cases of applied mean torsion load, but also in cases with purely axial loading or with biaxial configurations.