CONSIDERATION OF THE DUAL SCALE OF PORE SIZE IN WICKING - VALIDATION ON CARBON REINFORCEMENTS AND APPLICATION TO THE SWELLING OF BIO-BASED REINFORCEMENTS

摘要

In Liquid Composite Moulding (LCM) process, capillary phenomena occur during impregnation of a fibrous reinforcement. Capillary wicking in a fibrous medium is described by the Washburn's equation and then can be modelled through the Darcy's law where the driving force can be described as a capillary pressure. In case of natural fibres, Washburn's model is not sufficient to describe wicking because of water absorption that causes fibre swelling during liquid imbibition. In this study, a new model is proposed, taking into account the effect of fibre swelling at two scales: elementary fibres and yarns. These effects have been modelled and a modified approach of Washburn's theory has been developed to predict capillary wicking in fabric undergoing swelling in liquids.