Temperature Effects of a Sensing Element for CFRP Tension Cable Force Monitoring

ABSTRACT This paper combines the advantages of distributed long‐gauge fiber bragg grating (FBG) sensing technology to develop a novel monitoring sensing element (i.e., intelligent CFRP tendon) which is helically coupled with FBG sensor and CFRP tendon, to realize real‐time intelligent monitoring of CFRP tension cable force. Since FBG is sensitive to both temperature and strain, changes in ambient temperature can affect the strain monitoring accuracy of the intelligent CFRP tendon. Therefore, this paper conducts temperature sensing performance tests on intelligent CFRP tendons, analyzes the temperature effects under different parameters, and proposes a temperature compensation method for intelligent CFRP tendons. Derived through experimentation, the coefficient of variation of the temperature sensitivity of the intelligent CFRP tendon is 0.32%. The temperature sensitivity coefficient of the intelligent CFRP tendon is greatly influenced by the spiral groove inclination of the CFRP tendon; the dimension of the adhesive has less influence on the temperature sensitivity of the intelligent CFRP tendon. Through grey relation analysis, it is concluded that the relation value between the temperature sensitivity of intelligent CFRP tendon and the spiral groove inclination is 0.861. Based on the temperature sensing performance experimentation and grey relational analysis of intelligent CFRP tendons, a correction model for the temperature sensitivity of intelligent CFRP tendons is proposed. The corrected accuracy of the calculated value is improved by 1.43%~13.64%, which can be used for the temperature compensation calculation of intelligent CFRP tendon. It is of great significance to improve the accuracy of CFRP cable force monitoring in engineering applications.