Damage assessment of aero engine blade based on Lamb wave propagation theory and bandgap metamaterial

Abstract The blade structure plays a critical role in aero engines, directly influencing the safe operation of the entire aviation system. However, the harsh working environment of the blade often leads to various damages. The varying thickness across different sections of the blade structure poses a significant challenge in enhancing the efficiency of Lamb wave-based damage detection. To enhance the efficiency of blade damage localization and evaluation, this paper proposes a novel detection method combining Lamb wave propagation theory with a bandgap metamaterial structure. Firstly, the propagation characteristics of Lamb waves on blades with variable cross-sections are analyzed. Damage locations are identified, and corresponding imaging is performed using the delay-and-sum technique. Secondly, leveraging the principle of local resonance, the bandgap metamaterial structure is utilized to enhance the signal-to-noise ratio of the damage-reflected signals in blade damage detection. Lastly, four locations of simulated damage and actual cracks were set on the aero engine blade, and damage detection was carried out by attaching bandgap metamaterials. Compared with traditional methods, this approach can effectively filter out irrelevant interference signals, improve imaging performance, and accurately locate the damage of aero engine blade.