Modeling of Through-thickness Permeability for 3D Woven Fabrics

3D woven fabrics are widely used as reinforcement of composites, which are relevant to many applications. Permeability is one of primary properties in manufacturing of parts by liquid composite moulding. This paper proposes a new approach to describe through-thickness permeability for a unit cell, which is divided into three parts: flow perpendicular to warp and weft, flow parallel to binders and flow in open channels. An analytical model is proposed combining the three permeabilities, showing gap geometry, fibre arrangement and radius (r) and fibre volume fraction (V-f) all affect the total permeability. Two 3D fabrics (angle-interlock and orthogonal) were investigated with experimental results for the two fabrics compared with the analytical predictions, showing that the analytical model could predict the permeability with reasonable accuracy.