• A dynamic model of a cracked bladed disk considering root contact and aerodynamic loads is established. • Revealed how crack location influence the vibration characteristics of blade. • Established the relationship between crack location and fatigue life of blade. The compressor blades in gas turbines are prone to developing crack under complex loads including the centrifugal and the aerodynamic forces, the crack may lead to fatigue failure and pose significant threats to the safe and steady operation of the units. Considering the complicated contact conditions between the blade roots and dovetail grooves, this study constructs a dynamic analysis model for the impeller structure based on cyclic symmetry theory. The BlockLanczos method is employed to analyze the natural characteristics of blades under multiple conditions; the dual-linear shape function mapping approach is applied to impose aerodynamic time-varying loads on blade surfaces for transient dynamic analysis. By combining experimental test and numerical simulation, the damping of vibration response calculation is determined to ensure the accuracy of fatigue life analysis. The effects of root-dovetail contact modes and crack locations on the vibration characteristics and high-cycle fatigue life are investigated. This study is novel in the precise modeling and the fatigue analysis methodology for cracked blades. The research results demonstrate that the crack location significantly affects the 3 rd and 7 th natural frequencies of blades. Specifically, cracks in the middle blade notably reduce the 3 rd frequency by 11.8% compared to normal blade. The order of maximum vibrational amplitude from largest to smallest is the crack at the tip of the blade, no crack, root, and middle. Cracks at the blade roots exhibit more significant effects on fatigue life than those in mid-section or top regions, resulting in more substantial reductions in high-cycle fatigue lifetime.
Nan et al. (Sun,) studied this question.