A Study on Low-Frequency FBG Acceleration Transducer for Seismic Monitoring
Zhongchao Qiu, Yufeng Zhang, Jinquan Zhang, Yuntian Teng, Xiaomei Wang
Abstract
In response to the fact that it is difficult for current optical transducers to meet requirements on low-frequency seismic vibration monitoring, a low-frequency fiber Bragg grating (FBG) acceleration transducer designed with double curved beam reed as pickup structure was proposed, and its structural parameters were analyzed and optimized and tested in a low-frequency vibration test system. The result suggested that the acceleration transducer functioned at a natural frequency of 41 Hz and offered flat response at 2–32 Hz; its lower frequency limit, dynamic range, and sensitivity were 0.5 Hz, 76.8 dB, and 966.65 pm/g, respectively; the acceleration transducer exhibited favorable linearity and resistance to lateral interference. Compared with other FBG sensors for measuring low-frequency vibration characteristics, the weight of the double-curved beam reed FBG sensor is 200 g and the volume is only 40 cm3, which can provide reference for promoting the engineering application of the FBG acceleration sensor in the field of low-frequency vibration measurement.