Validation of Vibro-Acoustic Modulation of Wind Turbine Blades for Structural Health Monitoring Using Operational Vibration as a Pumping Signal

摘要

This paper presents a crack detection technique for wind turbine blades usingVibro-Acoustic Modulation. The technique identifies nonlinear characteristics of ablade by utilizing the wind turbine operational vibration as a pumping signal. Thetheory underlying the technique is described and an experiment with a 900 watt smallscalewind turbine is conducted using a wind tunnel. Two other conventional VibroAcousticModulation tests were also performed with same blades to compare theresults from these offline tests with the proposed online Vibro-Acoustic Modulationtest using the turbine operational vibration as the pumping signal. It is shown that thestructural vibration of the blades during operation lead to identical trends in themeasured Vibro-Acoustic Modulation spectra for the cracked blade as the case inwhich the impact and piezoelectric actuator narrowband pumping signals are used.