Fatigue Life Prediction of Notched Components after Plastic Overload Using Theory of Critical Distance

The aim of this work is providing a suitable method based on the theory of critical distance (TCD) to estimate the fatigue life of notched components in the presence of residual stress induced by the overload cycle. Presented method is relied on a virtual stress field to equalize the effects of real stress distribution in the hot spot around the notch root. This method is noted as equivalent virtual stress (EVS) method. The EVS method combined with some versions of the TCD method, such as the point method (PM) and line method (LM), were applied for two types of notched samples. Samples were made with U- and V-notches with axial stress concentration factors as 2.45 and 5.55, respectively. The test material was AA 2024-T3 due to its considerable resistance to fatigue failures. The PM was found more conservative, while LM showed more accuracy, especially when the critical distance parameter locates far from critical regions. A good agreement was observed between experimental and predicted results.