Acoustic Emission Monitoring of a 12m Wind Turbine FRP Blade during Static and Fatigue Loading


Emerging Technologies in NDT, 2000, pp. 59-66

D. Kouroussis, A. Anastasopoulos, P. Vionis, V. Kolovos, Eds. D. Van Hemelrijck, A. A. Anastasopoulos and T. Philippidis, A. A. Balkema


The structural integrity of a new, 12m, FRP Wind Turbine (W/T) blade was assessed by means of Acoustic Emission (AE) monitoring during full-scale, static and fatigue testing. The blade was loaded at a single point. The static loading envelope included stepwise loading, unload-reload cycles and load hold periods in the flapwise direction. Fatigue loading was applied by two hydraulic actuators, exerting forces at the flapwise and the edgewise directions simultaneously. AE data were recorded in real time by a ten-channel AE system. The AE measurements were complemented by mechanical measurements such as load and strain distribution across the blade. AE data processing included data filtering and application of various location techniques. The intensity of AE sources/events during the various loading stages was characterised by means of statistical techniques, distribution and cumulative plots. The results of the static tests revealed damage initiation and weak zones on the blade with high AE activity, which were further verified during fatigue loading.