Dynamic Reliability Analysis of Turbine Blades Under Combined High and Low Cycle Loadings

Turbine blades experience complex loading interactions induced by centrifugal loads, thermal loads, and vibration loads, which lead to the combined high and low cycle fatigue (CCF) failure. Considering the significance in acquiring sufficient data for reliability assessment, it may be imprecise to consider the load and strength as random variables. To deal with the issue, material parameters and working loads involved should be regarded as random variables, like high cycle fatigue stress and low cycle fatigue stress as well as material strength. Hence, the dynamic reliability model with strength degradation is developed based on conventional stress-strength interference theory to investigate the reliability of turbine blades under CCF loading conditions. The validation of the established model is performed by a numerical example, and the results indicate that the proposed model considering strength deterioration is in good coincidence with engineering practice.