Approach to Predict Near-Threshold Fatigue Crack Growth Rate in Heat-Treatment Residual Stress Field.

Abstract

Fatigue crack growth rates in a residual stress field can be predicted by using a superposition technique. This approach needs an analysis of residual and contact stress intensity factors as the authors proposed in previous papers. Objectives of this study are to discuss an approach for predicting the fatigue crack growth rates near the threshold where the oxide induced crack closure is dominant and to evaluate experimentally an effect of the residual plastic stretch on the crack surface contact. It is concluded that this approach gives a good prediction by the using upper bound of base metal crack growth rate data, and the residual plastic stretch has an effect on the crack surface contact stress.