Torsion measurement by using FBG sensors

In this paper we studied the potential of using FBG strain sensors to measure the torsion deformation theoretically and experimentally. FBG strain sensors are bonded on the surface of a shaft. When the shaft under torsion there is strain induced in the FBG sensor and the Bragg wavelength will shift accordingly. According to the wavelength shift and photoelastic properties of the FBG sensor bonded on the shaft the torsion deformation of the shaft can be obtained. In order to minimize the measurement error the optimal direction of the FBG sensor was obtained. The influence of the orientation deviation of the FBG sensor was discussed in detail. The feasibility of this method is demonstrated by experiment and the test results agree with the theoretical analysis very well.