Design and Optimization of an FBG Accelerometer Based on Single-Notch Circular Flexure Hinge for Medium-Frequency Vibration Measurement

This article proposes a novel hinge-type fiber Bragg grating (FBG) accelerometer for measuring medium-frequency vertical vibrations that employ a single-notch circular flexure hinge as the elastomer of the accelerometer. The proposed elastomer allows for the simultaneous realization of high sensitivity, a compact structure, and a relatively wide working frequency range, all of which are critical for accelerometer performance. The working principle and detailed theoretical analysis of the FBG accelerometer are illustrated and conducted. Moreover, the sensitivity of the accelerometer is optimized further through a genetic algorithm in order to strike a balance between miniaturization and resonance frequency. Finite element analysis and experimental tests were carried out to validate the performance of the accelerometer. The results indicate that the proposed FBG accelerometer has a resonant frequency of 800 Hz and a working frequency range of 50-450 Hz, with a sensitivity of approximately 65 pm/g at an exciting frequency of 100 Hz between the fiber central wavelength and vibration acceleration. The results also demonstrate that the proposed accelerometer exhibits a good linear relationship with the frequency of vibration accelerations, as well as good anti-interference properties with the horizontal vibrations. It has the potential to provide a novel and simple solution for monitoring medium-frequency vibration signals in complex environments characterized by high levels of electromagnetic interference (EMI), such as in aeronautical hydraulic systems.