The Application of Kinematic Hardening Model in the Study of Constitutive Model on the Condition of Non-proportional Multiaxial Fatigue Load

Fatigue life prediction of components is very complex when the material is under multiaxial non-proportional fatigue loading,and one of the key points in the field is about the prediction of the constitutive relationship of material. The problem is relatively simple in the elastic field,but material yield surface and the non-proportional hardening effect will be changed with the increase of plastic strain. So,isotropic hardening,kinematic hardening and nonproportional hardening effects must be considered in this process. This paper presents a general method to predict the constitutive relationship under multiaxial non-proportional fatigue loading by introducing multi-nonlinear yield surface and the generalized hardening modulus is used to reflect the combined hardening effects along with the plastic strain increment. Non-proportional multiaxial fatigue experiments of 316 L stainless steel validated the proposed method.