Stress gradient effects in fretting fatigue

This paper highlights the importance of high stress gradients in fretting fatigue. These pose a serious difficulty in attempting to employ plain fatigue data to predict fretting fatigue performance. Stress gradient effects may also be responsible for a size effect which is found to occur in many fretting situations. Here we review a number of possible approaches for dealing with high stress gradients. We then explore a notch analogy which might be used to generate equivalent stress gradients in plain fatigue. Some sample comparisons are given for typical dovetail geometries.