A generalized frequency separation–strain energy damage function model for low cycle fatigue–creep life prediction

Abstract

ABSTRACTFatigue–creep interaction is a key factor for the failures of many engineering components and structures under high temperature and cyclic loading. These fatigue–creep life prediction issues are significant in selection, design and safety assessments of those components. Based on the frequency‐modified Manson–Coffin equation and Ostergren's model, a new model for high temperature low cycle fatigue (HTLCF), a generalized frequency separation–strain energy damage function model is developed. The approach used in this model to reflect the effects of time‐dependent damaging mechanisms on HTLCF life is different from those used in all the earlier models. A new strain energy damage function is used to reduce the difference between the approximate strain energy and real strain energy absorbed during the damage process. This proposed model can describe the effects of different time‐dependent damaging mechanisms on HTLCF life more accurately than others. Comparing traditional frequency separation technique (FS) and strain energy frequency‐modified approach (SEFS), the proposed model is widely applicable and more precise in predicting the life of fatigue–creep interaction. Experimental data from existing literature are used to demonstrate the feasibility and applicability of the proposed model. A good agreement is found between the predicted results and experimental data.