Process and Structural Health Monitoring for Wind Turbine Applications using Optical Fibre Sensors

Abstract

As the wind energy industry rapidly develops, there is an increasing demand in process and structural health monitoring of wind turbine systems. In this study, two types of optical fibre sensors are developed. The first type is an embedded sensor to monitor the curing process of the composite wind turbine blades in manufacturing and to monitor the bending curvature of the blade in operation. The second type of sensor is an intensity-based bi-axial accelerometer, designed based on the light coupling between a vibrating cantilever fibre and two fixed receiving fibres. The working principle for both type of sensors are analyzed and prototypes are designed to test their performance experimentally. The proposed sensors are low-cost, light weight and easy-to-implement using a simple instrumentation system. To apply the developed sensor for structural health monitoring, a frequency-based method is developed for damage detection in beam structures. Numerical studies demonstrates the effectiveness of the method for location and severity identification. The effects of damage size and noise level are also studied numerically. The method are verified experimentally to detect damage in a vibrating beam under wind excitation.