Guided wave multi-frequency damage imaging method of aero-engine blades

The intricate structural characteristics and anisotropic material properties of aero-engine blades pose challenges to accurate damage detection of guided waves. This research introduces a multi-frequency damage imaging method for blades. By accounting for the curved propagation path resulting from thickness variations, this method enhances the precision of damage localization. The material anisotropy contributes to frequency-dependent velocity anisotropy. Damage locus identified through echo times at different frequencies converges solely at the damage site, reducing the sensor count required in the detection system. Experimental validation of curved propagation path and frequency-dependent velocity anisotropy in a blade is conducted. Damage localization within the blade is successfully achieved with only two sensors. The imaging results of the multi-frequency imaging method, exhibit the capability to diminish sensor requirements while enhancing imaging accuracy. This method holds promise for real-time monitoring of composite materials with variable thickness.