Simulation Study of a High Temperature Resistant Fiber Grating Strain Sensor

Fiber grating strain sensors are a common component of structural health monitoring systems. However, their refractive index decreases with increasing temperature, and the grating degrades at high temperatures, which presents a challenge for the deployment of fiber grating strain sensors in high-temperature environments. In response to this challenge, this paper presents a novel approach to developing a high-temperature-resistant fiber grating sensor. The proposed design incorporates a stainless-steel rhombic structure as the sensing substrate, a high-temperature adhesive as the bonding layer, and an aerogel thermal insulation material. COMSOL Multiphysics field simulation software was employed to simulate the strain transfer of the rhombic structure substrate when subjected to tangential strain, with the objective of optimizing the structural dimensions of the sensor. Additional simulations of the temperature change in the grating section of the sensor under a 500°C environment indicate that the temperature of the grating section remains below 120°C when the system reaches thermal equilibrium. This structure effectively mitigates the impact of temperature on the fiber grating. The structure serves to mitigate the impact of temperature on the fiber grating. It offers technical guidance for the deployment of fiber grating strain sensors in structural health monitoring systems.