Shock accelerometer based on fiber Bragg grating sensor with a novel 3D printed structure for medium frequency measurement applications and high acceleration range

This study aims to develop a shock accelerometer that can measure signals from two directions in onedimensional space for medium frequency measurement applications and high acceleration range. A fiber Bragg grating (FBG) sensor is attached to a structure fabricated using Fused Deposition Modeling technology (FDM) to achieve this. The finite element method is utilized to observe the sensor's operating mechanism and harmonic response, as well as to demonstrate the accelerometer's customizability. The sensor's design enables it to detect acceleration resulting from shock motion on both sides (+X and -X direction) of the Hopkinson bar system. When the elastic structure deforms, the wavelength inside the FBGs' core changes. During the test with different random accelerations, FBG1 showed a total Bragg wavelength shift of 6.403 nm within the 450 g to 1800 g range, while FBG2 showed a total shift of 2.033 nm within the 330 g to 1200 g range. According to the findings of the linearity analysis conducted on the proposed sensor, the linear values of the data obtained from FBG1 were over 96%, while those from FBG2 were close to 94%. In addition, the sensor's harmonic response was examined, and it was recommended that the sensor be operated within a frequency range of 20 to 600 Hz, with the resonant frequency being 660 Hz. The sensor's amplitude anti-interference is also considered negligible when the horizontal noise signal relative to the working axis signal is less than 3% in both directions. These findings suggest that the proposed accelerometer has great potential for various applications. Furthermore, the proposed FBG accelerometer sensor utilizes 3D printing technology, which offers several advantages, including rapid fabrication time, reduced production costs, and high customizability.