Improved temperature compensation of fiber Bragg grating-based sensors applied to structures under different loading conditions.

• Temperature compensation is discussed by considering interfacial action between the monitored structure and bonded FBG sensors. • Modified temperature-compensation function is proposed to enhance measurement accuracy of FBG sensors. • Effectiveness of the proposed function is validated by experiments. • Improved temperature-compensation measures for FBG sensors applied to structures under different loading conditions are suggested. • Hysteretic response time of FBG sensors is discussed and proper packaging design is experimentally proved to be feasible for decreasing the response time of FBG under thermal loading. Fiber Bragg grating (FBG) based sensors have been extensively used to monitor the deformation of structures (i.e., aircrafts, ocean platforms, bridges, tunnels, pavements and high-speed railways), for the advantages of absolute measurement, anti-electromagnetic interference, high precision, multiplexing and integration of sensing network over other sensors. However, due to the temperature-sensitive characteristics of FBG, temperature compensation should be considered to remove the thermal effect, so as to accurately reflect the strain information of the monitored structure. Traditional temperature-compensation method ignores the influence of the interfacial interaction between the structure and the bonded FBG on the measured data, which may lead to the compensated value smaller than the actual value. For this reason, modified temperature-compensation function with the influence of interfacial action considered is proposed to enhance the measurement accuracy of FBG based sensors. Laboratory tests on two kinds of samples under temperature loading have been conducted to validate the effectiveness of the proposed function. Improved temperature-compensation measures for FBG based sensors applied to structures under different loading conditions (i.e., high and low temperature, static and dynamic mechanical load) are discussed, with the temperature hysteresis of FBG sensing elements considered. The study in this paper presents a scientific instruction for the better interpretation of testing data measured by FBG sensors and the accurate use of FBG sensors for the temperature and strain detection of structures in engineering [ABSTRACT FROM AUTHOR]