Design and test of a low frequency Fiber Bragg Grating acceleration sensor with double tilted cantilevers

The collection of low-frequency vibration signals is very important for the monitoring research in various fields such as national defense engineering, bridges and dams, aerospace, and the earthquake resistance of civil building structures. During the structural design of existing cantilever Fiber Bragg Grating (FBG) acceleration sensors, the tilt angle of the cantilever is often ignored, therefore, aiming at this problem, this paper proposed a new FBG acceleration sensor with double titled cantilevers, and used formula derivation and ANSYS software to optimize the structural parameters of the proposed sensor and conduct simulation analysis. Then, according to the simulation results, two sensor prototypes were fabricated, one with tilted cantilevers and the other with horizontal cantilevers, then, the performance of the two was tested, compared, and analyzed to verify the impact of the tilt angle of cantilevers on the performance of the sensor. The experimental results showed that, the natural frequency of the proposed sensor was about 46 Hz, which can be used to monitor vibration signals with the 6-30 Hz frequency range; the sensitivity of the proposed sensor was about 4.16 pm/m s(-2); and its degree of lateral an-interference was less than 5.62%. Compared with the sensor with horizontal cantilevers, the flat response area of the sensor with tilted cantilevers increased by about 30%, while its sensitivity reduced by about half. The research findings of this paper provide a useful reference for the research on similar type sensors and further expansion of the measurement range of FBG acceleration sensors.