Multiparameter Optimization and Adaptive Temperature Compensation for FBG Strain Sensors in Wide-Temperature-Range Aerospace Applications

Accurate strain measurement in cryogenic fuel pipelines is crucial for ensuring the structural integrity and reliability of rocket engine systems operating under extreme thermal conditions. Fiber Bragg grating (FBG) sensors show significant potential for such applications; however, their inherent temperature-strain cross-sensitivity limits performance over wide temperature ranges. This research presents an enhanced compensation strategy combining multi-parameter optimization with temperature-zone-specific adaptation to improve the accuracy and stability of FBG-based strain sensing in harsh aerospace environments. Four special steel substrate materials including S03, S06, S07, and 1Cr18Ni9Ti, were evaluated using strain transfer theory and thermo-mechanical coupling simulations. Genetic algorithms optimized key design parameters, which were validated through experimental testing from 77 K to 433 K. S03, S06, and S07 exhibited favorable cryogenic performance, achieving an average strain transfer efficiency of approximately 87% at extreme temperatures. Conversely, 1Cr18Ni9Ti demonstrated the highest strain transfer efficiency at high temperatures, exceeding 95% at 433 K, with a temperature sensitivity of 30.44 pm/K and a compensation error below 2.63 με. The implementation of segmented temperature self-compensation further reduced residual strain fluctuations to within 0.5 με. This method significantly enhances the reliability of FBG sensors for high-precision strain monitoring under extreme temperature conditions, offering a practical solution for critical aerospace instrumentation.