Influence of flow-induced deformations of fabrics on the formation and transport of bubbles during liquid moulding processes

The viscous flow-induced deformation of non-crimp fabrics during liquid moulding processes, such as resin transfer moulding, and its influence on the creation of bubbles behind the liquid front are studied. A transverse flow with a low Reynolds number through random arrays of aligned cylinders is considered with account of changes in the transverse permeability of fibre bundles. A combined methodology of directly solving the two-dimensional Navier-Stokes equations for the flow in the vicinity of a single fibre and minimization of the dissipation rate in a system of fibres is employed. Sethian's level set method is used for transient calculations of the motion of the liquid-gas front, at which the capillary pressure is accounted for. The continuity is maintained, and local correlations between the dimensions of neighbouring gaps formed between bundles are used. The elastic deformations of the fibre bundles are calculated based on micromechanical analyses. The void fractions of inter- and intrabundle bubbles obtained differ for deformable and non-deformable fabrics, but both the cases compare well with those from real mouldings.