Fracture Monitoring of Composite Wind Turbine Blade Using High-Speed Bragg Grating Sensor System

Abstract:

This paper introduces a FBG (fiber Bragg grating) based AE (acoustic emission) sensing system for use in health monitoring of composite wind turbine blades. In this study, a multiplexing high speed FBG sensor system was developed with a spectrometer-type demodulator based on a linear photo detector. Pencil break test was performed using an FBG sensor and the results were compared with the results of piezo-based AE sensor. For the performance test of fracture sensing in composite materials, a down-scaled wind turbine blade was fabricated and drop impact tests were performed. Arrayed 4 FBG sensors were installed in the skin of wind turbine blade and impacts of 15 J energy were applied by a drop weight. The frequency characteristics of impact induced AE signals were examined with short-time Fourier transform focused on the leading waves. Finally, the onset of fractures in composite structure was successfully assessed using arrayed FBG sensors.

• Periodical: Applied Mechanics and Materials (Volume 109)
• Pages: 79-83
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.109.79
• Online since: October 2011
• Authors: Hyung Joon Bang, Soo Hyun Kim
• Keywords: Blade, Damage Assessment, Fiber Bragg Grating (FBG), Structural Health Monitoring (SHM), Wind Turbine (WT)

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