Experimental and numerical study on dynamic behavior evolution of cracked blade-disc
Weiwei Wang, Hong Guan, Sainan Zhou, Hui Ma, Xumin Guo
Abstract
Cracks in blade-disc structures of aircraft engines seriously threaten flight safety. This study conducts vibration-based crack propagation experiments on both intact and pre-cracked blade-discs. The characteristics of crack propagation at various stages are analyzed, and the experimentally obtained crack paths are incorporated into a dynamic model to simulate vibration evolution during propagation. The model is verified through experiments and numerical simulations. Furthermore, predictive models are established to characterize the relationships among crack length, resonance frequency, and load cycles, including a direct mapping between resonance frequency and crack length. Results indicate that cracks in the intact blade-disc propagate radially, with the resonance frequency decreasing gradually at first, then more rapidly. For pre-cracked blade-discs, the crack initially propagates along the pre-crack direction and then transitions to radial propagation, accompanied by a resonance frequency decline rate shifting from rapid to stable. The proposed dynamic model and findings can provide theoretical support for life prediction and crack fault diagnosis of blade-disc.