The Research on High Sensitivity Large-Range Strain Sensor Based on Composite Material Substrate Fiber Bragg Grating

In the complex and demanding flight environment, critical sections of aircraft wings with composite structures can experience significant strains, reaching up to 10000 μ ε. Existing fiber optic grating sensors for large strain measurements often have lower sensitivity. To enhance the sensitivity of the fiber optic grating sensor for large strain measurements, a multi-layered, sensitivity-adjustable encapsulation structure is proposed. Through an analysis of strain transfer mechanisms among the sensor structures, coupled with finite element simulations, the impact of key sensor parameters on sensitivity is assessed. Response surface optimization is employed to optimize the sensor design. A highly sensitive fiber optic grating sensor for large strain measurements is fabricated based on simulation results and subjected to calibration testing. The results indicate that the sensor exhibits a range of up to 10000 μ ε with a linearity of 0.9996, an average sensitivity of 0.317 pm / μ ε, and demonstrates good repeatability. This composite-based fiber optic grating sensor effectively addresses the challenges in monitoring large strains in aircraft composite structures.