SRM lifetime prediction rule for the creep - fatigue interaction regime supported by a suitable constitutive model

The application of conventional lifetime prediction methods requires a certain knowledge about the stress-strain response of a material to the applied load. This should preferably be simulated by an appropriate constitutive model. The empirical rule of strain rate modified linear accumulation of creep damage (the SRM rule) for the lifetime prediction of metallic materials in the creep-fatigue interaction regime has been supported by Chaboche's viscoplastic constitutive model. An inherent criterion for the validity of a given prediction has been defined. The application of the proposed method and its ability to predict life expectancies in various cyclic loading conditions, different from those fatigue tests required for the calibration of the SRM rule, has been shown using the IN 738 LC superalloy as an example.