A Tension-and-Compression Strain Gauge Coupled With Fiber Bragg Grating

This study presents a dual-mode strain gauge integrated with Fiber Bragg Grating (FBG) technology for simultaneous measurement of tensile and compressive strains. A flexible hinge-bridge structure is employed to amplify longitudinal deformation into transverse strain, enhancing sensitivity and enabling real-time temperature compensation through a paired-FBG configuration. The sensor was designed and optimized using Finite Element Method (FEM) analysis, fabricated from AISI 304 stainless steel via laser cutting, and experimentally validated under controlled loading. The results demonstrate high sensitivities of 8.08 pm/με (tension) and 26.56 pm/με (compression) with excellent linearity (R² up to 0.987) and FEM–experiment agreement within 3.5% deviation. The proposed sensor achieves high repeatability, temperature stability, and bidirectional operation, offering a compact and reusable solution for precision strain and structural health-monitoring applications.