An enhanced stress field intensity approach for fatigue life assessment combining notch and size effect

The notch characteristics of engineering components significantly impact their fatigue lives. Accurately analyzing the notch effect and size effect is of great significance for structural integrity evaluation, which provides insights into the extent of fatigue failure in engineering structures. In this paper, a new method is proposed for determining the fatigue failure region based on actual elastic-plastic stress distribution under various notch geometries and applied loads. It considers the complex mechanical behavior of the plastic effect and stress relaxation near the notch root. Furthermore, a novel weight function is employed to consider the relative stress gradient at all points within the fatigue failure region. Finally, an enhanced stress field intensity approach is developed to predict notch specimens fatigue lives utilizing experimental lives of smooth specimens. Additionally, the effectiveness of the proposed method is analyzed by predicting the fatigue lives of three distinct materials notched specimens with varying geometries and applied loads. The prediction absolute errors of the proposed approach are compared with those of the other traditional notched fatigue analysis methods. The comparative results indicated that the performance of the proposed method outperforms the other methods.