The effective stress range as a mean stress parameter

Abstract This investigation examines the hypothesis that variations in the crack opening stress level of short cracks can account for the observed variations in fatigue strength with mean stress under constant-amplitude cyclic loading. Support for the hypothesis is provided by the experimental data generated for a 2024-T351 aluminium alloy and a SAE 1045 steel. Based on the observed variations in crack opening stress with mean stress an effective stress range is postulated as a mean stress parameter. The effective stress range successfully reduces the fatigue data for all levels of mean stress to a unique fatigue-life curve for each material.