Design and investigation of a reusable surface-mounted optical fiber Bragg grating strain sensor

This paper describes the structure design, parameters optimization, and performance test of a fiber Bragg grating strain sensor with features of surface-mounting and reusability. Flexure hinges are adopted in the design of a key elastic body. Number of mounting holes, sealing, sensitization, and stiffness of the sensor have been considered and optimized. Then, sensor prototype has been manufactured and fully tested. The experimental results show that the stiffness and the sensitizing coefficient are identical to design the values. Test results also show that the sensor provides a sensitivity of 3.357 pm/με with a fitting linear correlation coefficient of 0.9999, a measurement range of ±600με, a repeatability error of 2.73%, and a hysteresis error of 4.67%. Furthermore, good creep resistance and good capability for alternating strain measurement have also been demonstrated. These results promise the sensor potential applications in structural health monitoring.