Monitoring and controlling manufacturing for composite using fiber Bragg grating

Composite Compression Molding Process is one of the most popular manufacturing technology of polymeric matrix composite. Temperature and pressure are the most import parameters and have a great influence on structure quality. Improper temperature cycle may induce significant residual stresses in composite, while improper pressure-applied moment and magnitude may effect the fiber distribution along the thickness of composite. Fiber Bragg grating (FBG) was used to monitor the temperature evolution and residual stress of composite laminates during the cure process. Temperature evolution was taken into relationship of epoxy resin chemo-rheological model and concluded the real-time viscosity during the manufacture. The different viscosity selected to applying pressure according to the real-time monitoring temperature. The residual strain of composite laminates which manufactured by Compression Molding Process at different pressure-applied moments were compared. The proper pressure-applied range was determined and the best properties of the laminates were obtained in it. Examination experiment was done in which the fixed viscosity value was taken as a signal when pressure was applied. Closed loop controlling and digital production are performed.