Monitoring Curing of Quasi-Isotropic Carbon Fiber/Epoxy Composite Using Fiber Bragg Grating Sensors

Abstract

In this study, four fiber Bragg grating (FBG) sensors were embedded into a quasi-isotropic carbon fiber/epoxy composite material to monitor curing. The spectra of the FBG sensors were shifted and deformed during the curing process. This phenomenon is caused by residual strain during composite curing. We monitored the spectral changes of the embedded FBG sensors in different laminate layers to measure the residual strain during curing. According to the experimental results, the curing residual strain of the composite was generated first from the central layer. The maximum axial and lateral residual strains measured by the FBG sensors were −456.7 and 1234.6 µε, respectively. The FBG sensors have advantages for use in the stress-strain sensing of composites.