Fractal permeation characteristics of preforms used in liquid composite molding

Abstract Preform permeability plays a critical role in the analysis of mold filling during liquid composite molding processes. Because of the complex structure of the preform pore network, a quantitative description of the pore structures, and consequently, the evaluation of the permeabilities presents a major challenge. In this article, a fundamental description of the disordered preform pore structures based on fractal techniques is utilized to relate the preform permeabilities to the actual microstructures in terms of two fractal dimensions. Comparison of the fractal permeation model predictions with experimentally‐measured permeabilities demonstrates excellent agreement over a wide range of fiber volume fractions, injection pressures, and isotropic and anisotropic preform architectures.