A creep damage model for low cycle fatigue based on the equivalent creep stress: Establishment, verification and application

Abstract A method for calculating the creep damage during low cycle fatigue (LCF) (tensile plasticity reversed by compressive plasticity, PP) controlled by strain rate e was proposed. According to the equivalent principle of creep damage with the same reduction in cross section, a creep damage model considering a continuously changing stress was established based on the equivalent creep stress σ en , which was determined by the total creep damage, the actual creep time (the total time of tensile loading stage in the whole process of fatigue), and the fatigue life during LCF (PP). For Sanicro 25 alloy, σ en first increases quickly, and then increases linearly and slowly with increasing e . Based on the creep damage model, the total creep damage and fatigue life under different e were predicted accurately. To study the application of the method for calculating the creep damage, the creep damage model for 316 stainless steel was established and verified. At a constant e , when γ decreases or K increases, the creep damage decreases and the fatigue life increases. Based on the variation trend, the engineering application of the creep damage model was discussed.