Measurement of process-induced stresses in composite laminates by FBG sensors

Based on Fiber Bragg Grating (FBG) sensing technology, a method is provided to monitor the process induced stress of composites in real-time. In-situ monitoring of the process-induced stress of unidirectional and cross-ply laminates is implemented, then the residual strain and stress formed in cure process are acquired. Based on the classical laminate theory, the macro-residual strain and stress induced by thermal and chemical shrinkage in cure process are studied. FBG sensor can be used as a novel tool to monitor the cure process and analyze residual stress of composites, and make it possible to monitor composite structures from manufacture stage to service stage continuously.