Damage detection in a laboratory wind turbine blade using techniques of ultrasonic NDT and SHM

This paper presents a case study in the use of ultrasonic NDE/SHM techniques for detecting and locating damage in a real (but small) wind turbine blade. Two techniques are considered: (1) non-linear acoustics, and (2) guided-wave “pitch-catch” SHM. While the non-linear acoustics approach proved disappointingly insensitive to damage induced experimentally in the blade, the guided-wave approach not only detected the damage but also proved capable of locating it, using a “network of novelty detectors” methodology. A first, slightly ill-conceived, programme of guided-wave tests actually provided valuable insight into attenuation of waves in the structure of interest and supported the idea that actuator-sensor networks of a feasible density could be used for wind turbine blade SHM.