Probabilistic Model of Mean Stress Effects in Strain-Life Fatigue

This paper proposes a modification of the Walker model to account for the mean stress effect on fatigue life of structures and the associated scatter of experimental data. To account for various sources of uncertainty, a framework which permits dealing with run-outs and provides an analytical probabilistic definition of the whole strain-life field, both in the low-cycle and high-cycle fatigue regions is used. The proposed model is an improvement relative to the Smith-Watson-Topper model for materials that are significantly more or less sensitive to mean stress. Model's applicability is shown for various metals.