Real-time monitoring of composites’ fabrication and in-service loading

The increased use of composites in critically loaded structural applications requires a bigger effort on the optimisation and reliability of the manufacturing process. A distributed optical fibre sensor is embedded in a fibre reinforced composite laminate, to give three sensing regions at different levels through-the-thickness of the plate. This study follows the resin infusion process during fabrication of the composite, monitoring the development of strain in-situ and in real time, and in addition to gain a better understanding of the resin rheology, identifying accurately the gelation point and polymerisation process that could lead to improved cure cycle. Mechanical four point bending demonstrates the sensitivity and versatility of the technique.