Damage Detection in Wind Turbine Blade Panels Using Three Different SHM Techniques

A comparison of three different damage detection methods is made on three nominally identical glass reinforced composite panels, similar to the load carrying laminate in a wind turbine blade. Sensor data were recorded in the healthy state and after the introduction of damage by means of a four–point bending quasi–static test. Acceleration sensors, PZT transducers and the piezoelectric excited Lamb waves were used for the measurements of the panels. All three methods are based on the comparison of the healthy and damaged structure. The first method is statistical covariance–driven damage detection using a subspace–based algorithm, where one damage indicator for all three panels was computed. The second method is based on PZT transducers and the A0 mode of Lamb waves propagating in the panel, making use of the reflection of the signal at damage in the panel. The third method is based on the estimation of modal parameters of the intact and damaged panel using pLSCF and following their deviations. The results from these three damage detection methods are compared and discussed.