Low-frequency fiber Bragg grating accelerometer based on an elliptical flexure hinge lever amplification mechanism

To address the demand for low-frequency vibration monitoring in transportation infrastructure, an FBG accelerometer incorporating an elliptical flexure hinge lever amplification mechanism was developed. A theoretical model was constructed to calculate the sensor’s sensitivity and resonant frequency, while a genetic algorithm was used to optimize the sensor’s structural parameters. Furthermore, a finite element model was constructed for modal analysis, followed by experimental verification conducted on a low-frequency vibration platform. The findings show that the sensor has a resonance frequency of 81 Hz, a sensitivity of 256.25 pm/g within the 1–45 Hz operating range, and a linearity greater than 0.996. The transverse interference remains below 5.74%, indicating a strong transverse anti-interference capability. Featuring simple fabrication and ease of packaging, the proposed sensor is highly suitable for vibration monitoring in complex environments.