Bend type fiber Bragg grating crack sensor with big measurement range

Fiber Bragg grating (FBG) sensing technique has been widely applied to structual crack monitoring due to its advantages over other sensors. However, the meausrement range of FBG sensors is small due to easy breakage of silica fiber. In this paper, using current research results for reference, a simple bend type FBG crack sensing setup was designed. The performance of the sensor was verified through experiments. The experimental results show that the crack sensing of the sensor is reliable, the measurement range can be extended a lot compared with traditional FBG crack sensors, and that the sensor possesses good repeatability to cope with the uncertainty of crack development.