Numerical modelling of liquid infusion into fibrous media undergoing compaction

In the present paper, an overall model for the study of a non isothermal fluid flow across a highly compressible porous medium is proposed, in order to be included into a finite element software. This model can be applied to a wide range of activities, and as an application it is used here to model dry route composite manufacturing processes. Indeed, it is to be noted that the spreading of these promising processes fails due to the absence of a numerical model able to capture the resin infusion across the compressed preform thickness. The main difficulty being that this infusion results from a pressure prescribed over the deformable preform/resin stacking involved. From the modelling point of view, problems of this multi-physical analysis are two fold. First the coupling of liquid regions, ruled by Stokes equations, with the fibrous preform regions governed by a Darcy's law, yield badly posed boundary conditions. Second, the interaction phenomena due to the resin flow in the highly compressible preform are not classical. The model developed here includes a modified Beaver-Shaffman-Joseph condition to couple Stokes and Darcy zones, and is based on an ALE formulation of the liquid flow across the deformable porous medium in which finite strains are accounted for with an updated Lagrangian scheme. These mechanical models are also coupled with thermo-chemical models, accounting for resin reticulation under the temperature cycle prescribed by the processing equipment. (c) 2007 Elsevier Masson SAS. All rights reserved.