A closed form solution to describe infusion of resin under vacuum in deformable fibrous porous media

Abstract

In composites manufacturing, when the preform is compacted and the resin is drawn under vacuum, the resin flow can be modelled using Darcy's Law in deformable fibrous porous media. The compaction of the preform and the resin pressure are coupled. The governing equations for resin flow and compaction are presented. An analytical solution for one-dimensional flow in the axial direction and compaction in the thickness direction is derived that includes the local deformations of the porous medium and compaction effects on permeability. The coupling between flow and compaction is introduced with arbitrary constitutive laws that describe permeability of the material as a function of fibre volume fraction and a non-linear elastic material equation for compaction. The important implications of the results to composites manufacturing are discussed.