Fatigue life prediction under multiaxial loading

A unified multiaxial fatigue life model for isotropic and anisotropic materials is proposed. The proposed fatigue model is a critical plane-based model. Most of the earlier models based on the critical plane approach assume that the critical plane only depends on the stress state. In the current model, the critical plane not only depends on the stress state but also on the material property. The critical plane is theoretically determined by minimizing the damage introduced by the hydrostatic stress amplitude, which makes the proposed model have almost no applicability limitations with respect to different materials. A wide range of fatigue data, which covers both brittle and ductile metals, isotropic and anisotropic materials are chosen to validate the proposed methodology. Generally, the predictions based on the proposed model agree with the experimental observations very well.