Design and Application of a Fiber Bragg Grating Tension Sensor for Anchor Rope

A fiber Bragg grating (FBG) tension sensor for anchor rope has been proposed and implemented in the full-scale impact test of rockfall protection barriers in this paper. According to the measurement principle of the tension sensor, the wavelength shift difference of the two FBGs which, respectively, measure the positive and negative strain in the spring element is utilized as sensing signal. Therefore, the force sensitivity is increased and the temperature cross-sensitivity is compensated. Experimental results indicate that the measurement sensitivity is 14.85 pm/kN in a range from 0 to 150 kN. The dynamic forces on anchor ropes in barriers have been clearly recorded by the designed sensors during the impact test, and the variation of the impact forces could be mainly divided into three stages. This kind of tension sensor is expected to be widely used for force's quasi-distributed measurement or remote monitoring in industrial and mechanical fields