Experimental Research on Damage Identification of Wind Turbine Blade by PZT Wave Based Method

The vast majority of the world's wind turbine blades are used of composite materials, and crack damage is common failure mode of wind turbine blade. Therefore, a reliable nondestructive testing (NDT) method is required to detect the crack damage. In this paper, the crack damage for a composite plate which is part of the wind turbine blade is experimentally researched by using piezoelectric ceramic to determine the damage location and level. A group of piezoelectric ceramics is pasted on the surface of the composite plates with the artificial crack damage. One PZT patch is applied as an actuator, the others as sensors. An experiment for the crack damage detection is performed by using sine sweep wave generated by actuating PZT patch. Based on the Fourier spectra analysis on the received signals, the artificially mimicked crack area has been successfully detected and the defined damage index is used to judge the crack damage level.