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In resin transfer molding processes, the edge effect caused by the nonuniformity of permeability between fiber preform and edge channel may disrupt resin flow patterns and often results in the incomplete wetting of fiber preform, the formation of dry spots, and other defects in final composite materials. So a numerical simulation algorithm is developed to analyze the complex mold-filling process with edge effect. The newly modified governing equations involving the effect of mold cavity thickness on flow patterns and the volume-averaging momentum equations containing viscous and inertia terms are adopted to describe the fluid flow in the edge area and in the fiber preform, respectively. The volume of fluid (VOF) method is applied to tracking the free interface between the two types of fluids, namely the resin and the air. Under constant pressure injection conditions, the effects of transverse permeability, edge channel width, and mold cavity thickness on flow patterns are analyzed. The results demonstrate that the transverse flow is not only affected by the transverse permeability and the edge channel width but also by the mold cavity thickness. The simulated results are in agreement with the experimental results.

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At the reactive mould‐filling stage in resin transfer moulding (RTM) processes, the correlation analysis of epoxy/amine resin cure, structure and chemorheological behavior plays a key role in the optimum control of RTM processes. A new methodology used to simulate the reactive resin flow in RTM processes with edge effect is presented in this article. The recursive approach and the branching theory are used to describe the evolution of molecular structure and resin viscosity, respectively. And then the resin flow process is simulated by means of a semi‐implicit iterative calculation method and the finite volume method. The results reveal the proposed resin cure‐structure‐viscosity model provides excellent agreement with the experimental viscosity data during the RTM filling process. It is also observed that the curing reaction causes the inhomogeneous distribution of resin conversion and resin molecular weight in the mould cavity, which will result in the spatially structural and performance inhomogeneities in the finished products. With the injection temperature or the edge width increasing, the discrepancy of resin conversion and resin molecular weight in the mould cavity is more evident. This study is helpful for understanding the complicated relationship among the processing variables, resin structures, and properties. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers