A fiber Bragg grating vibration sensor based on crossed variable section beam

Abstract

This paper presents a triaxial vibration sensor that can be used for vibration acceleration detection. The main body of the elastic structure of the sensor is a variable section beam. The fiber Bragg gratings (FBG) are applied to the surface of the crossed variable section beam. The theoretical equation for the sensitivity of this sensor is given by the theoretical analysis of material mechanics. The simulation of modal analysis was carried out by means of the finite element method. The resonant frequencies of the proposed fiber Bragg grating triaxial sensor in the Z, X, and Y directions are 363.01 Hz, 466.34 Hz, and 466.82 Hz, respectively. Finally, the sensor was calibrated and tested in each direction of vibration, and the results showed that the sensitivity of Z, X, and Y directions were 6.66 pm/g, 4.61 pm/g, and 4.61 pm/g respectively, which proved that the FBG sensor has good sensing response for vibration in three directions.