Modification Lemaitre Damage Accumulation Model with Metastable Austenitic Steels under Fatigue

Abstract A modification of the Lemaitre damage accumulation model that takes into account strain–induced martensitic transformation is proposed for metastable austenitic steels. The influence of the strain–induced martensite, accumulated microdamage and internal stresses on the dynamic Young’s modulus and density of the material was taken into account. Expressions have been obtained for calculating the Young’s modulus of the intact austenite and the change in the effective Young’s modulus due to the relaxation of residual stresses after the first cycles of elastic–plastic deformation. For the first time, the knee point of the fatigue curve between the low–cycle and high–cycle fatigue regions is presented in terms of the intensity of strain induced martensite formation. A comparison of the damage parameter calculated within the proposed model and the classical Lemaitre damage accumulation model was carried out. A method for individual life prediction at the final stage of structure evolution based on acoustic measurement data is proposed.