Calibration Test of Force-measuring Bolt Based on Fiber Grating

Based on the fiber grating sensing principle and force sensing characteristics, the force-measuring bolt with fiber grating was designed. From the mechanics analysis, the mathematical relationship was determined between the axial force of bolt and the fiber grating center wavelength, then the corresponding mechanical calibration test was carried out. The results showed that the shift amount of fiber grating center wavelength had a good linear relationship with the load, the linearity degree was 0.994 5 and the measuring precision was high. The fiber grating sensor had the sensitivity coefficient of 0.013 2 nm/kN, which was basically consistent with theoretical analysis. The test analysis showed that the anchor working state monitoring was feasible with fiber grating sensing technology.