Hinge-type FBG acceleration sensor based on double elastic plate

Zhongchao Qiu,Zhitao Gao,Yuntian Teng,Jinquan Zhang,Li Hong

doi:10.1038/s41598-021-03628-7

Abstract

It is critical for the health monitoring of large-scale structures such as bridge, railway and tunnel to acquire the medium-frequency and high-frequency vibration signals. To solve the problems of low sensitivity and poor transverse anti-interference of the medium-frequency and high-frequency fiber acceleration sensor, a hinge-type Fiber Bragg Grating(FBG) acceleration sensor based on double elastic plate has been proposed, and the hinge and elastic plate are used as elastomer to realize the miniaturization and transverse interference suppression of the sensor. The MATLAB and the ANSYS are used for theoretical analysis and optimization of sensor sensitivity and resonance frequency, structural static stress analysis and modal simulation analysis, while the test system is built to test the sensor performance. The results show that the resonance frequency of the sensor is 1300 Hz; the sensor has a flat sensitivity response in the middle-high frequency band of 200–800 Hz; the sensitivity is about 20 pm/g, and the fiber central wavelength drift and acceleration have good linearity and stability, while the transverse anti-interference is about 3.16%, which provides a new idea for monitoring of medium-frequency and high-frequency vibration signals in large-scale structures.

Highlights

It is critical for the health monitoring of large-scale structures such as bridge, railway and tunnel to acquire the medium-frequency and high-frequency vibration signals
Mechanical vibration signals can be divided into low frequency, medium frequency and high frequency signals according to the frequency, and the high frequency vibration signals are signals with a frequency greater than 1 kHz
This paper presents a hinge-type FBG acceleration sensor based on double elastic plate, which can realize the miniaturization and transverse interference suppression of the sensor with the hinge and the elastic plate as elastomer

Summary

The elastic coefficient of the fiber kf is

Where, Af is the cross sectional area of the fiber, and Ef is the elastic modulus of the grating. (8) and (10), it can be known that some key parameters of the sensor, including the minimum thickness between hinges t2 , the semi-minor axis of the elliptical hinge c , the semi-major axis of the elliptical hinge b , the bottom width of the elastic plate b1 and the thickness of the elastic plate t1 , all can influence the sensitivity and resonance frequency significantly, and these parameters can be adjusted greatly in the fabrication of the sensor. From the analysis on structural parameters, it can be known that the sensor sensitivity and resonance frequency will be influenced significantly when the semi-major axis of the elliptical hinge b , the semi-minor axis of the elliptical hinge c , the bottom width of the elastic plate b1 and the thickness of the elastic plate t1 change little.

Sensor test and analysis

Conclusion

Author contributions

Findings

Additional information