The Influence of Capillary Flow on Edge Effect in Resin Transfer Moldinga

Abstract

A model has been developed for analyzing the capillary flow along the edge of the unidirectional fiber mats. The model is based on the existence of two flow regions of resin, namely, the porous media region formed by fiber mats and the fiber free gap region between the wall and the fiber mats. The lubrication approximation is used to simplify the resin flow equation in the gap, while Darcy's law is used to calculate the flow fields in the fiber mats. Results show that 2KD 5 is the critical gap size for the consideration of the edge effect. Capillarity cannot be neglected for such a little gap as the injection pressure is low. Relationship analogous to the Washburn one is used to simplify the capillary flow. Results show that the mechanism of formation of dry spots is eliminated in the case with low injection pressure. Based on the experimental data for the TGFM-300 P/E random fiber mat, the correlation between the quasi-steady capillary pressure and the other properties of fibrous network is proposed by Buckingham Xr theorem. The body-fitted finite element method is used in the numerical simulation.