Development of a Large-Range FBG Strain Sensor Based on the NSGA-II Algorithm

To monitor large deformations in dovetail tenon joints of Dong ethnic wooden drum towers, this study designs a large-range Fiber Bragg Grating (FBG) strain sensor based on the FBG sensing principle. The NSGA-II algorithm is utilized to optimize the packaging structure of FBG strain sensors. Consequently, an adaptive optimization methodology for its packaging configuration is proposed. This study sets the optimization objectives as a 5000 με measurement range and 0.1 pm/με sensitivity. It employs the NSGA-II algorithm to optimize the structural dimensions and material properties of the large-range FBG strain sensor. This process yields three combinations that meet the requirements for monitoring large deformations in dovetail tenon joints of Dong wooden drum towers. Subsequent linearity experiments were conducted to verify the sensitivity stability and measurement range of the three large-range FBG strain sensors. The results show that within the measurement range of 0–6000 με, all three sensors achieve a strain sensitivity of 0.099 pm/με, with a fitted linear correlation coefficient of 0.999.