Development of a Spindle-Type FBG Pressure Sensor for Pressure Monitoring at the Wind Turbine Foundation Ring–Concrete Interface

This study presents a fiber Bragg grating (FBG) pressure sensor with a spindle-type protective structure, optimized using the NSGA-II algorithm, for monitoring pressure variations at the contact interface between wind turbine foundation rings and concrete. To optimize the sensor sensitivity and measurement range, the NSGA-II algorithm was employed to determine the optimal structural dimensions and material properties of the spindle-type sensor. This approach addresses two critical challenges: firstly, enhancing the survivability of FBG pressure sensors in harsh service environments, and secondly, enabling accurate monitoring of weak pressure signals at the foundation ring–concrete interface. Linearity verification tests demonstrate a sensor sensitivity of 55.01 pm/MPa within a 10 MPa measurement range, accompanied by a linear correlation coefficient of 0.999, confirming high stability of the fabricated sensors. Furthermore, wind turbine foundation model experiments validate the practical service performance of the proposed sensor. Results indicate that the spindle-type FBG pressure sensor not only withstands severe operating conditions but also achieves real-time monitoring of interfacial pressure changes in foundation ring–concrete systems.