In the first year we have made significant progress in understanding the micro-scale behaviour of reinforcements during manufacture by resin infusion. We have characterised the fibre distributions within tows (fire bundles) within composite reinforcements, and have developed a detailed statistical description of these. This has been used to generate virtual models, which have been used within CFD studies to simulate flow during infusion. Steady-state simulations allow the distribution of tow permeabilities to be predicted, and here a key discovery is that the mean value is almost an order of magnitude lower than that predicted by (previously accepted) analytical models. Transient flow simulations are now starting to determine the conditions for void formation.
At the meso-scale (unit cell level) we have used MRI to image the flow of fluid through reinforcement during infusion. This is the first application of this approach to composites manufacture, and we have used this to identify void formation between tows.
Work on cure modelling will also focus on variability, and here a stochastic simulation methodology is being developed to study the uncertainties/ performance tradeoffs in cure processes. Initial work has focused on reviewing the key sources of variability and implementing a robust methodology to model composite cure and distortion that allows efficient incorporation of variability information. The work currently focuses on the development of a Monte Carlo scheme for uncertainty simulation of cure and the development of a sensing setup that will allow the estimation of surface heat transfer variability in an industrial environment.