Permeability characterization of sheared carbon fiber textile preform

Fabric deformation alters its local permeability characteristics which, in turn, influences the resin infusion process. This work investigates the radial permeability test method of sheared carbon fiber textile reinforcement materials for the purposes of infusion modeling. A novel experimental approach is described, which utilizes a customized Matlab video processing code to track fluid flow and calculate permeability using data from the complete flow field. Results show principal permeability values, K1 and K2, to increase and decrease, respectively, from a near isotropic state as the fabric shear angle increases, yielding a K1/ K2 ratio of 3.74 at the maximum measured shear angle of 40°. Detailed statistical analysis revealed significant error for cases where fewer than 16 measurement directions were used for the permeability calculation, particularly in highly anisotropic samples.