An equivalent crack growth model for creep fatigue life prediction of metals

A new creep fatigue life prediction model based on the equivalent crack growth analysis is proposed in this paper. The model is based on existing observations on the fatigue crack propagation and creep void evolution mechanisms for some metallic materials. Equivalent initial crack and void are randomly distributed in the material and their equivalent growth under creep-fatigue loadings is simulated. Pure fatigue and creep rupture testing are used to calibrate the model parameters. Arbitrary strain-based or stress-based creep-fatigue testing results are used for prediction validation. Experimental data from open literature and from in-house testing for two metals are compared with the proposed model predictions. General good agreement is observed. Some conclusions and future work are drawn based on the proposed study.