Aeroengine Disc Simulation Specimen Fatigue Life Prediction Using Modified Critical Distance Theory

The turbine disc is a critical component of an aeroengine, where the mortise experiences severe stress concentration due to the notch effect, making it a vulnerable position for disc fatigue failure. In this study, the simulation specimens were designed based on the mortise structure. Fatigue tests were conducted to explore the failure mechanism under fatigue loading. Elastic-plastic finite element analyses were performed subsequently to investigate the distribution of local mean stress and stress gradient near the notch. Considering the influence of local mean stress and stress gradient, a novel fatigue life prediction method was proposed based on the theory of critical distance (TCD). This method overcomes the disadvantages of the TCD in which the critical distance cannot be determined beforehand and the requirement of a complex iterative process when predicting fatigue life. By using this method, the predicted fatigue life of the simulation specimens under different loads is within [Formula: see text] error factor.