The Structure Of The Fiber Bragg Gratings Vibration Acceleration Sensor Design And Experimental Research

The demand of automatic measurement and high-precision test in structural health monitoring of large civil engineering and seismic wave detection of oil and gas exploration and other fields is increasingly high, which means that vibration sensor must not only meet the higher requirement of accuracy, reliability, stability and other indicators, but also have the capability of data processing, self-test, self-calibration and self-compensation, even some fields also need multi-function vibration sensor measuring multiple parameters simultaneously. As a kind of vibration sensor, fiber Bragg grating (FBG) accelerometer not only has the characteristic of small size, light weight, high sensitivity, fast response, large dynamic range, long life and anti-electromagnetic interference, but also can realize the detection of distributed, networked, real-time online in a large area. Compared with traditional machinery and electronic accelerometer, FBG accelerometer has many intrinsic advantages, so it deserves people’s favor.On the base of FBG sensing theory, combined with the basic design principle and method of FBG accelerometer, the paper developed two one-dimensional FBG accelerometer based on steel capillary and U-shaped cantilever beam and verified the static performance and dynamic performance by experiments. Furthermore, the paper designed a three-dimensional FBG accelerometer based on steel capillary and demonstrated its feasibility by experiments. Experimental research results showed that the natural frequency one-dimensional FBG accelerometer based on steel capillary is2200Hz and35Hz respectively, frequency response range is from OHz to1000Hz and from OHz to20Hz respectively, sensitivity is1.99pm/g and209.66pm/g respectively when it’s placed vertically and horizontally. Experimental research results showed that one-dimensional FBG accelerometer based on U-shaped cantilever beam has the natural frequency of170Hz, frequency response range from OHz to120Hz, sensitivity of about100pm/g with good frequency detection function and cross-axis anti-interference degree. The feasibility of three-dimensional FBG accelerometer proposed in the paper detecting space acceleration has been demonstrated by sensitivity test experiment and vibration input-output response experiment. It can be concluded from experimental results that one-dimensional FBG accelerometer proposed in the paper may be applied in structural health monitoring and seismic wave exploration detection.