Dependence Of The 1-D Permeability Of FibrousMedia On The Fibre Volume Content: ComparisonBetween Measurement And Simulation

Abstract

Since the beginning of this decade a growing interest of the industry in the Liquid Composite Moulding (LCM) processes could be observed. These manufacturing methods meet the requirements of today's series productions of advanced continuous fibre reinforced composite. There are several examples of successful series productions in RTM (Resin Transfer Moulding) and VARI (Vacuum Assisted Resin Infusion), but currently the use of the full potential of these processes is restricted by the limited knowledge of the resin flow behaviour in fibrous media. To improve this situation, several sophisticated flow simulation software packages have been developed during the last 5 years to help the process engineer to optimise mould design and process parameters. This study deals with LCMFLOT which is a very promising software developed by the Centre de Recherche Appliquee sur les Polymeres (CRASP) in Montreal. A basic condition to obtain a useful flow simulation is accurate permeability (k) measurement of the fibrous medium. The permeability depends on fibre volume content (Vf). In many applications the permeability varies along the flow path in the part according to draping. Therefore it is very important to characterise the dependence of the permeability on a wide range of Vf. An experimental study was performed in a 1-D flow channel to quantify the dependence of the permeability from Vf. The material using is an isotropic (k%=ky=k) non-crimped fabric fibre (biaxial glass fibre, +/45°). A model fluid Transactions on Engineering Sciences vol 21, © 1998 WIT Press, www.witpress.com, ISSN 1743-3533