Modelling Tow Impregnation of Woven Fabric Reinforcements and Its Application in Liquid Composite Moulding Process Modelling

This paper proposes a detail physical model for the micro-scale flow in plain woven reinforcements. The modelling results are formulated into a mathematical algorithm which is then directly incorporated into a continuum dual-scale model as a ‘sink’ term. When used to model liquid composite moulding (LCM) processes, this incorporated dual-scale model demonstrates the fact that the impregnation of fibre tows lags behind the resin front in macro pore spaces. The modelling results are in agreement with the experimental observations. It has been shown that the unsaturated region at the flow front could increase or have a fixed length under different circumstances. These differences are explained due to the variation in tow impregnation speed (or the time required for the tow to become fully impregnated) which is related to the weave infrastructure and the nesting and packing of plies. The modelling results have also demonstrated the drooping of the inlet pressure when the flow processes are carried out under constant injection rates.