Determination of corner and edge permeability in resin transfer molding

Resin flow in resin transfer molding may be strongly influenced by small heterogeneities in the fiber preform, such as narrow channels formed by bending and fitting into a mold. An evaluation of preform permeability in these regions of nonuniform packing is presented. The study incorporates an empirical and analytic approach to iteratively determine the permeability in these regions. Flowfront data were recorded for high fiber volume fraction woven fiber preforms. Edge gap width, injection pressure, and fiber volume fractions were varied. The flow front data were compared with numerical simulations to estimate enhanced permeability at the edges. The results indicate that, for high fiber volume fraction preforms, flow in the channel dominates for relatively small (≈ 2 mm) gaps.