Design and analysis of a high-sensitivity FBG accelerometer with a flexural bearing

To address the increasing demand for high-precision measurement and miniaturization in FBG accelerometers, this paper proposes a high-sensitivity FBG accelerometer based on a flexural bearing. The spiral-shaped through-grooves of the flexural bearing significantly enhance the sensitivity of the diaphragm-type FBG accelerometer while inheriting its simple structure and compact size. Initially, the theoretical model of the accelerometer was derived. Subsequently, a set of optimized dimensions for the accelerometer was selected and investigated using the finite element method. Finally, the measurement performance of the accelerometer was verified through a series of calibration tests. The results showed that the accelerometer achieved a sensitivity of 379.8 pm/g (at 20 Hz) and a resonant frequency of around 230 Hz, with a cross-axis sensitivity of less than 7.3 % of the main axis. Leveraging the advantages of a compact structure, small volume, and, this novel accelerometer holds promise for expanding the application of fiber optic accelerometers.