A CCF life prediction model based on iso-damage curves considering effect of load sequence

A Combined Cycle Fatigue (CCF) life prediction model considering the effect of load sequence was proposed. To account for the interaction of high and low cycle fatigue, the CCF load was divided into two different loading paths of variable stress amplitude and stress ratio. Based on the iso-damage curves, a CCF life prediction model independent of fitting parameters was proposed, agreeing well with the experimental results. Finally, the effect of load sequence on CCF was discussed according to the fracture morphology of designed blade-like specimen. The results showed that the predicted CCF life was almost located in three-fold dispersion band for the LCF-HCF (LH) and HCF-LCF (HL) loading paths, especially for the average results of both. Compared with other models, the proposed model had better predictive and generalization abilities for multiple materials and variable experimental conditions.