关键词: 发动机轮盘；疲劳寿命；应变比；多元线性回归；体积效应

Abstract: The strain-life fatigue models with mean strain effect are often employed to estimate fatigue lives of disks in aero-engine， however， the prediction accuracy of fatigue-life models commonly used are unsatisfactory under certain conditions. Therefore， a new strain-life fatigue model was proposed to accounting for the effect of any strain ratio among the strain ratios of fatigue test data sets， and the parameters in the new model can be determined by fatigue test data with various strain ratios through multiple linear regression. The estimated results of four commonly used fatigue life models， including the new model proposed in this study， were compared with the fatigue test data of CC450 stainless steel， SAE 1045 steel and standard bars and tension specimens with center-hole of GH4133 superalloy. It was found that the prediction accuracy of both the Morrow mean stress correction model and the Morrow-Harford model were unstable for different materials， while the SWT model showed acceptable accuracy with stable predictive capability. By contrast， the new model proposed in this paper showed superior accuracy to any other candidate mean strain relationships. The estimated lives of CC450 stainless steel and SAE1045 steel were basically within the double scatter band， and the results of the standard bars of GH4133 superalloy was merely 0.25% higher than fatigue test data; while the estimated life of tension specimens with center-hole was just 3.76% less than the experimental fatigue life. Thus， this new model showed satisfactory capability to estimate fatigue life with stain ratio effect for different materials.

Key words: Aero-engine disk；Fatigue life；Strain ratio；Multiple linear regression；Volume effect