Applying video magnification for vision-based operating deflection shape evaluation on a wind turbine blade cross-section

Abstract

Phase-based motion estimation and video magnification are non-contact and target-less efficient approaches that are being used to extract the operating deflection shapes of vibrating structures. In recent years, Operational Modal Analysis (OMA) and Experimental Modal Analysis (EMA) as the most well studied structural dynamics identification tools have benefited from the unique advantages that phase-based motion estimation and video magnification can offer. Within this study, the phase based motion estimation and video magnification techniques are adopted to perceive the operational deflection shapes and dominant vibration patterns in a Wind Turbine Blade (WTB) cross-section. Moreover, the estimated resonant frequencies are validate by the commercial accelerometer measurements as well that indicates the reliability of the results provided by phase-based motion estimation and video magnification. The identified vibrational operating deflection shapes and the resonant frequencies can be valuable information for design enhancement, as well as finite element model updating and model validation. Moreover, subcomponent structural studies can utilize the results obtained from the vision-based OMA test on the cross-section of the wind turbine blade.