A model for fibre washout during high injection pressure resin transfer moulding

High injection pressure resin transfer moulding is a variant of resin transfer moulding in which the preform is compressed in a tool and resin is injected into the mould under very high pressure. The high injection pressure (>20 bar) introduces possible fibre washout that translates into manufacturing defects or causes inconsistencies in processing and leads to scatter in mechanical properties of composite parts. A model is presented which quantifies and provides insight into the influence of process variables such as clamping force and injection pressure on fibre washout distance (the one-dimensional model assumes a rigid preform). A generalised one-dimensional stress model for fibre washout is presented for regions that are impregnated with the resin and the regions that are dry. The model shows fibre washout to be significant at the beginning of the injection process. The model allows one to further refine the injection strategy by adjusting injection pressure to account for washout in high injection pressure resin transfer moulding.