Research on the Response Performance of Fiber Bragg Grating Sensors in Hypergravity Environments

In hypergravity centrifugal model tests, sensors serve as the core components for acquiring critical experimental data. Fiber Bragg grating (FBG) sensors, owing to their advantages of miniaturization and quasi-distributed integration, have been widely applied in hypergravity experiments. However, the mechano-optical coupling response mechanism of FBG sensors under high-g conditions still lacks systematic investigation. This paper first examines the mechano-optical response characteristics of FBG strain sensors through hypergravity tests, and systematically analyzes the influence of the metallic housing and the viscoelastic encapsulation medium on the sensor's service performance. On this basis, an in-situ calibration device suitable for hypergravity environments was independently developed, a standard force value traceability method was established, and the nonlinear mechano-optical response of the sensor was precisely evaluated up to 100 g. The results indicate that although the metallic housing of the earth pressure sensor can suppress zero drift, it reduces sensitivity and resolution. The sensor sensitivity exhibits a nonlinear increase with the g-value, tending to stabilize in the range of 80 g to 100 g, whereas the zero drift shows a linear increasing trend with the g-value. Furthermore, the viscoelastic encapsulation medium, while suppressing zero drift, reduces the measurement resolution. Based on the above results, a numerical model of the performance evolution of the earth pressure sensor under a hypergravity field was established, revealing the influence of geometric configuration and material properties on the sensor's zero drift, and structural optimization recommendations for reducing zero drift were proposed. The research findings provide a reference for the use of fiber Bragg grating sensors in geotechnical hypergravity centrifugal model tests.