Strain measurement for composite tubes using embedded, fiber Bragg grating sensor

Composite tube structures have been extensively used in automotive, aerospace and aircraft industries. In addition, the fiber Bragg grating (FBG) sensor, a distinctive non-destructive tool, has begun to play an important role in structural health monitoring (SHM). This study aims to prove the feasibility of the FBG sensor integrated into a composite tube structure. Uniform FBG sensors are separately embedded in circumferential and axial directions of a glass fiber-reinforced plastic (GFRP) tube to detect the strain changes under loading. Two experiments, an inner pressure test and an outer concentrated force test, are conducted to investigate the deformation characteristics of the composite tube. The strain measurement results from the FBG sensors are compared with those of resistance strain gauges and FEM analysis. The results demonstrate that the FBG sensor can be successfully used for in-service structural health monitoring of the composite tube.