Out-of-autoclave (OOA) processes are gaining attention for their cost-effectiveness, promoting the use of liquid resin infusion techniques. However, challenges such as void formation and dry spots during resin impregnation remain problematic. While simulations help optimize mold design, conventional models often overlook intra-bundle impregnation, focusing mainly on macroscopic flow between fiber bundles. Since resin also flows within the bundles, considering intra-bundle permeability is essential for accurate modeling. This study proposes a method to evaluate intra-bundle permeability in both axial and transverse directions. For axial flow, unidirectional fiber bundles were enclosed in a heat-shrink tube, with resin infused under atmospheric pressure and vacuum applied at the opposite end. For transverse flow, bundles were wrapped around a cylindrical metal tube and infused laterally. Flow rates were measured, and permeability was calculated using Darcy’s law. This approach offers valuable data to improve the fidelity of impregnation simulations and mold design.
SAKAI et al. (Wed,) studied this question.