Numerical simulation for the transverse impregnation in resin transfer molding

A model has been developed for the transverse impregnation of the resin into a continuous unidirectional packed fiber bundles. The model takes into account two types of flow, namely the macro-flow around the fiber bundles and the micro-flow around the fibers in the bundles, occurring simultaneously. Both flows are described by Darcy's law. Results show that an elliptic type void is formed within the fiber bundle under certain circumstances. The void will soon shrink to nothing soon if vacuum assistance is applied in the mold, while it is mobilized and compressed if vacuum assistance is not applied in the mold. By the similarity analysis, we also show that the initial size of the trapping air depends merely on the ratio of permeability between the micro-flow and macro-flow, but not on the injection pressure and the resin viscosity. The numerical simulation is based on the body-fitted finite element method.