A generalized hysteresis energy method for fatigue and creep-fatigue life prediction of 316L(N)

Creep-fatigue interaction is extremely important for the life prediction of structural components subjected to high temperature conditions. The widely used life prediction methods such as time fraction rule and ductility exhaustion method are found to be insufficient in long time regimes and cannot give a clear physical explanation for the material failure. In this paper, a generalized life prediction model is proposed on the basis of the hysteresis energy and law of energy conservation. The influence of hold time on the cyclic stress-strain behavior is described based on isochronous stress-strain curves and stress relaxation during hold time is evaluated with the time hardening rule. An analytical approach is set up to calculate the hysteresis energy for the creep-fatigue tests. The generalized hysteresis energy is used as a model parameter to predict the fatigue and creep-fatigue life of 316L(N) and it is found to have a power law relationship with the number of cycles to failure. The fatigue and creep-fatigue life predicted with the new energy-based method shows a good correlation with the experimental results from different researchers.