Design of vibration sensors based on fibre Bragg grating type composites for earthquake detection and early warning application

Abstract

Composite materials can be rapidly moulded using additive manufacturing processes due to their excellent mechanical and physical properties. Combining fibre Bragg gratings with composites results in high-performance fibre grating vibration sensors that address the limitations of electrical sensors and traditional materials. This study focused on developing a fibre optic acceleration sensor that utilizes a parabolic column made of silica gel. The sensor underwent fabrication, packaging, and calibration using a dedicated test system. Parametric calibrations and vibration detection tests were conducted to evaluate the performance of the system. The experimental results indicate that the sensor exhibits an intrinsic frequency of 70 Hz, a flat response range of 5 to 40 Hz, a linearity coefficient greater than 0.99, effective control of transverse interference, and exceptional low-frequency response, which improves the detection of vibration signals. Therefore, the sensor’s low intrinsic frequency and exceptional low-frequency response make it well-suited for detecting vibrations at low to medium frequencies.