A multi-cantilever beam low-frequency FBG acceleration sensor

The acquisition of 2-50 Hz low-frequency vibration signals is of great significance for the monitoring researches on engineering seismology, bridges & dams, oil & gas exploration, etc. A multi-cantilever beam low-frequency FBG acceleration sensor is proposed against the low sensitivity that predominates in the low-frequency vibration measurement by FBG acceleration sensors. Structural parameters of the sensor is subjected to simulation analysis and optimization design using the ANSYS software; the real sensor is developed based on the simulation results in the following manner: Three rectangular of the cantilever beams are evenly arranged around the mass block at 120 degrees to improve the sensitivity and alleviate the transverse crosstalk of sensor; in the end, a performance test is performed on the sensor. According to the research findings, the sensor, whose natural frequency is approximately 64 Hz, is applicable for monitoring the low-frequency vibration signals within the range 16-54 Hz. The sensor sensitivity is approximately 87.955 pm/m s(-2), the linearity being greater than 99%, the transverse interference immunity being lower than 2.58%, and the dynamic range being up to 86 dB. The findings offer a reference for developing sensor of the same type and further improving the sensitivity of fiber optic acceleration sensor.

Automated summary

This study addresses the issue of low sensitivity in FBG acceleration sensors for low-frequency vibration measurements by proposing a multi-cantilever beam low-frequency FBG acceleration sensor. The sensor, optimized through simulation analysis, exhibits high sensitivity and low transverse crosstalk, making it suitable for monitoring low-frequency vibration signals within the range of 16-54Hz. Performance tests show that the sensor has a sensitivity of approximately 87.955 pm/m s^(-2), with a linearity exceeding 99% and a transverse interference immunity below 2.58%.