Embedded Fiber Bragg Grating Sensors for Industrial Composite Cure Monitoring

An embedded Fiber Bragg Grating (FBG) strain sensor and an FBG temperature sensor have been shown to be able to accurately monitor the industrial composite cure process of a glass/ epoxy plate devoted to aeronautical applications. The internal absolute strain level in the plate was determined, free of temperature effect thanks to a differential method. After curing, a residual compression strain of about -0.22% was observed, which represents a short part of the range in compression for a single mode fiber. Later on, the embedded FBG strain sensor could be used as a smart sensor for the health monitoring of composite structures, e.g. for impact or layer delamination detection.