Curing Monitoring of Graphite/Epoxy Laminated Composite Material by Using Embedded Corrugated Long-Period Fiber Grating Sensor

The curing monitoring of polymeric composite materials is necessary to improve the mechanical performance, especially for the characterization of residual stress after manufacture. We aimed to explore the use of embedded corrugated long-period fiber gratings (CLPFG) to characterize the curing process in a graphite/epoxy composite material. The curing development and residual stress measurement were assessed through changes in the shape of the optical spectra, intensity attenuation, and shifts in wavelengths in the optical fiber sensors. By monitoring the spectra of the CLPFG during the curing process, the maximum axial residual stress induced by the curing process was 35 MPa in the composite material.