A novel creep–fatigue interaction damage model with the stress effect to simulate the creep–fatigue crack growth behavior

Abstract

In this paper, a novel creep–fatigue interaction damage model was proposed to evaluate damage evolution and crack growth behavior in creep–fatigue regime. The model incorporated the maximum stress effect into the low cycle fatigue damage accumulation and utilized the non-linear summation approach to consider the creep–fatigue interacted effect. The model could predict the relation between (da/dt)avg against (Ct)avg in creep–fatigue interacted environment and demonstrate the crack growth behavior under pure fatigue condition, which respectively matched well the corresponding experimental results. In addition, the crack growth rate was greatly dependent on the dwell time in creep–fatigue regime. The crack growth rate (da/dt)avg was increased with decreasing the hold time at the same (Ct)avg values. During crack growth process, the creep damage accounted for a larger portion compared with the fatigue damage. Furthermore, in creep–fatigue regime, the effect of the initial crack depth on crack growth behavior was dependent on the hold time while the applied initial stress factor range had slight effect on the crack growth behavior.