Analytical prediction of void formation in geometrically anisotropic woven fabrics during resin transfer molding

The present study constructs a mathematical model for inter-bundle void formation in a geometrically anisotropic woven fabric, taking into consideration the gap between the mold and a woven fabric in the thickness direction. This gap effect is modeled by defining apparent intra-bundle domains that consist of fiber bundles and a gap between the bundle and the mold surface. By calculating the capillary pressure and permeability, which are linked to the apparent intra-bundle flow, a qualitative coincidence with experimental results of resin flow–velocity dependence on fingering and void formation was obtained. The relationship between fabric anisotropy and optimal flow velocity was also investigated, and it was found that the optimal flow velocity changes non-linearly with respect to the geometric anisotropy of the fabrics and the preferable flow direction.