A survey on fatigue life analysis approaches for metallic notched components under multi-axial loading

In this paper, several fatigue failure approaches of metallic notched components under multi-axial loading in recent decades are reviewed in detail. They are classified into three categories according to their different fatigue physical mechanisms and hypotheses: nominal stress approach, local stress-strain approach and the theory of critical distance. The accuracy, applicable range and computing complexity of these three different fatigue failure theories of metallic notched specimen under multi-axial fatigue loading are given. It is concluded that theory of critical distance accords with experimental results under multi-axial fatigue loading and it gives unambiguous explanation for physical mechanism of fatigue damage. However, the computing process is complex, especially under non-proportional fatigue loading, and the key parameter of theory of critical distance is difficult to calculate especially in engineering. These difficulties limit the application of theory of critical distance.