FIBER BRAGG GRATING SENSORS FOR FATIGUE MONITORING OF COMPOSITE WIND BLADES

摘要

Fiber Bragg grating sensor can be used to monitor the mechanical behavior of composite wind blade. The internal strain of composite wind blade during a constant and variable stress amplitude fatigue testing process was monitored with fiber Bragg gratings sensors. FBG sensors as a fatigue indicator can reveal Young's modulus decrease of the specimen, which is a direct index of damage. FBG sensors can not only be embedded in composite blades to detect fatigue damage, but also have excellent durability compared with other sensors such as electric strain gauges. After 1 million cycles, the FBG sensors can still keep good sensibility. FBGs as a fatigue indicator are a novel sensor to monitor, evaluate and give crash alert for the health state of composite wind blades during their whole service life.