Predicting the fatigue life of machined specimen based on its surface integrity parameters

Fatigue is one of the main reasons for the failure of structural components. In practical engineering, machined surface integrity, including geometrical parameters, mechanical parameters, and metallurgical parameters significantly influence the fatigue life of structural parts. However, due to the unclear correlations of these parameters, there is no fatigue life prediction model that takes all three kinds of surface integrity parameters into account. In this paper, a framework for fatigue life prediction model is proposed in which the effect mechanisms of geometrical, mechanical, and metallurgical parameters to fatigue life were distinguished. Then, the practical model based on the proposed framework was established using specified integrity parameters: stress concentration factor (SCF), surface residual stress, and work hardening effect related metallurgical parameter. The prediction accuracy of the proposed model is compared to those of other models with 5 experimental data sets; the results show that better average prediction accuracy is achieved by the proposed model.