Assessing variable amplitude multiaxial fatigue lifetime of notched components based on the notch critical plane approach

In the present paper, the notch critical plane method proposed by the authors is extended from 2D- to 3D-cases. The plane passing through the assumed critical point and experiencing the maximum variance of the resolved shear stress is defined as the the notch critical plane. The linear-elastic stress fields around the notch root are fitted via polynomial functions. The relationship between critical distance, l, and fatigue damage, Db, under variable amplitude loading blocks is proposed. Susmel’s parameter and a specific multiaxial cycle counting method are incorporrated into this approach to estimate multiaxial variable amplitude fatigue life. Numerous fatigue data generated by testing five different notched metallic materials were collected from the literature to check the accuracy of the proposed approach. This validation exercise allowed us to demonstrate that this method is highly accurate, with the majority of the predicted experimental results falling within an error band of 2.