Shandong Earthquake Agency, Ji'nan 250014, China.
Institute of Disaster Prevention, Sanhe 065201, China.
Rev Sci Instrum. 2023 Mar 1;94(3):035010. doi: 10.1063/5.0134374.
Temperature measurement is of great significance for research in the health monitoring of large structures and earthquake precursors. Against the frequently reported low sensitivity of fiber Bragg grating (FBG) temperature sensors, a bimetallic-sensitized FBG temperature sensor was proposed. The sensitization structure of the FBG temperature sensor was designed, and the sensor sensitivity was analyzed; the lengths and materials of the substrate and strain transfer beam were analyzed theoretically; 7075 aluminum and 4J36 invar were chosen as bimetallic materials, and the ratio of the substrate length to the sensing fiber length was determined. The structural parameters were optimized; the real sensor was developed, and its performance was tested. The results suggested that the sensitivity of the FBG temperature sensor was 50.2 pm/°C, about five times than that of a bare FBG sensor, and its linearity was more than 0.99. The findings offer a reference for developing sensors of the same type and further improving the sensitivity of the FBG temperature sensors.
温度测量对于大型结构健康监测和地震前兆研究具有重要意义。针对光纤布拉格光栅（FBG）温度传感器灵敏度低的问题，提出了一种双金属敏化 FBG 温度传感器。设计了 FBG 温度传感器的敏化结构，分析了传感器的灵敏度；从理论上分析了基底和应变传递梁的长度和材料；选择 7075 铝合金和 4J36 因瓦作为双金属材料，并确定了基底长度与传感光纤长度的比值。对结构参数进行了优化；制作了实际传感器并对其性能进行了测试。结果表明，FBG 温度传感器的灵敏度为 50.2 pm/°C，约为裸 FBG 传感器的五倍，线性度大于 0.99。该研究为同类传感器的研制提供了参考，进一步提高了 FBG 温度传感器的灵敏度。
