A study on FBG accelerometer for low-frequency vibration monitoring

Accurate acquisition of low-frequency vibration signals is of great significance in fields such as seismic monitoring and structural health monitoring. To address the challenge of fiber Bragg grating (FBG) accelerometers in effectively capturing low-frequency vibration signals, a low-frequency FBG accelerometer based on a cross-spring leaf is proposed. First, the theoretical model of the accelerometer is established and its working principle is analyzed; second, the structural parameters of the sensor are optimized under multi-constraint conditions using the gray wolf optimizer algorithm, and the accelerometer is simulated and analyzed through COMSOL; finally, a low-frequency vibration test platform is constructed for performance testing. Experimental results indicate that the accelerometer has a natural frequency of 58 Hz, a sensitivity of 1194.91 pm/g, a cross-interference of less than 4%, a repeatability relative standard deviation of 0.90%, and a linearity of 99.98%. It exhibits a flat response between 0.3 and 40 Hz, providing a reference for the application of FBG accelerometers in low-frequency vibration monitoring.