Collaborative Deformation Modified Hinge-Linkage Unit Model for Optimal Design of High-Sensitivity Optical Fiber Strain Sensor

In this paper, we present a fiber Bragg grating (FBG) strain sensor based on flexible hinges and a general modeling method for its hinge-linkage unit. The method considers the collaborative deformation of flexible hinges and linkages simultaneously and establishes a strain-sensitized model of the sensor based on this unit. This model is applicable to developing mathematical models for the sensors that utilize the hinge-linkage unit design, resulting in an average increase of 30% in model accuracy. On this basis, we achieved global optimization of the sensor’s sensitivity using an optimization algorithm. The hinge-linkage unit model and the sensor strain sensitization model were verified using ANSYS software. Afterward, we physically encapsulated the sensor with a small-diameter optical fiber, subsequently completing a sensitivity test and a temperature compensation test. We have theoretically discovered that the sensor sensitivity can reach up to 101.02 pm/με, consistent with the simulation results. Experimental tests have shown that the sensors have a strain sensitivity of up to 58.769 pm/με.