Analysis of damage localization based on acoustic emission data from test of wind turbine blades

Acoustic emission (AE) is the transient elastic waves within a solid material caused by the rapid release of localized stress energy such as the formation of cracks when a material is subject to mechanical loading. This study investigates AE-signals generated from internal manufacturing flaws embedded in both a 14.3 m and a 31 m long wind turbine blade when they are under cyclic loading in a full-scale structural test. We are particularly interested in the spatial origin of these signals to localize damage within the structure. We perform spatial analysis on the frequency and energy of AE-signals and their positions in an industrial-scale blade. We find that, while tracing AE-signals back to the embedded manufacturing faults is straightforward, the acoustic wave properties are inconsistent throughout different test phases, which challenges the correlation between acoustic wave properties to the damage location. More reference test data should be collected to establish these correlations. This study provides insights into better utilizing AE-data for reliable structural health monitoring of wind turbine blades.