Cumulative Damage Concepts In Thermomechanical Fatigue

A recently developed cumulative creep-fatigue damage model is applied to the prediction of thermomechanical and isothermal cumulative creep-fatigue loading histories. The model utilizes damage curve expressions to describe cumulative damage evolution under creep-fatigue conditions, qualitatively grouped according to dominant damage mechanism or mode. The damage coupling concept of McGaw is employed to describe the cumulative interaction among different mechanisms and modes. In this study, experiments consisting of two-level loadings of thermomechanical fatigue (both in-phase and out-of-phase) followed by isothermal fatigue to failure, were conducted on 316 stainless steel. It was found that the model gave good predictions for the out-of-phase two-level tests and provided reasonable bounds for the in-phase two-level tests.