Study on Fiber Grating Pressure Sensor Based on Flexible Composite Structure

With the rapid increase in the number of knee replacement surgeries, how to reduce the incidence of intraoperative soft tissue imbalance has become a key issue that needs to be addressed. At present, the assessment of the soft tissue balance of the knee joint mainly relies on the personal experience and subjective judgment of the surgeon, and reliability and stability are often difficult to ensure. In order to meet the needs of knee joint pressure monitoring, a fiber grating pressure sensor based on a flexible composite structure package is developed. First, the physiological structure of the knee joint and the sensing theory of fiber Bragg grating (FBG) are introduced. Subsequently, the finite element software is used to mechanically simulate the pressure-bearing process of the sensor. Finally, the pressure calibration experiment of the sensor is completed. The results show that the pressure measurement range of the sensor is $0\sim 100$ N, the pressure sensitivity is 0.0068 nm/N, and the linearity ${R} ^{{2}} \gt 0.99$ , which meets the requirements of knee joint pressure monitoring. The results of this article also provide insights into the application of FBGs in soft tissue balance measurement of the knee joint.