Reinforcement of partially cured aerospace structures with B-staged patches

This research presents analytical models to describe the cure kinetics of an epoxy resin, and then implements the models to create partially cured carbon fibre reinforced polymer structures that have been locally reinforced. A full process for co-curing B-staged composite parts was developed, including cure kinetic and glass transition modelling of the curing reaction of the epoxy resin, simulation of curing cycles, development of the tools and optimisation of the process. A 50 % improvement in the bearing load was achieved with the B-stage patch and reinforcement co-cure solution that is proposed. Moreover, the bearing strength was found to more than double with the incorporation of steel foils into the bearing region of the structure. The development of these models, and the promising results show that increased bearing performance may be achieved whilst still meeting stringent qualification regulations for commercial aviation application using this processing technique.