Prediction of fatigue life under multiaxial loading by using a critical plane-based model

Based on the critical plane concept, a simple model is proposed to estimate fatigue lives of metals subjected to both proportional and non-proportional loadings. In the proposed model, both parameters of shear and normal strain ranges are considered in the equivalent strain which is made with both parameters by means of the von Mises criterion. The maximum normal stress acting on the maximum shear strain range plane is introduced in the proposed model to take into account the effects of non-proportional hardening. Procedures used to determine the damage parameters acting on the plane of maximum shear strain range are also presented.