International audienceIn 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 BeaverShaffmanJoseph 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

Elastic compression is the process of applying an elastic garment around the leg, supposedly for enhancing the venous flow. However, the response of internal tissues to the external pressure is still partially unknown. In order to improve the scientific knowledge about this topic, a slice of a human leg wearing an elastic garment is modeled by the finite-element method. The elastic properties of the tissues inside the leg are identified thanks to a dedicated approach based on image processing. After calibrating the model with magnetic resonance imaging scans of a volunteer, the pressure transmitted through the internal tissues of the leg is computed. Discrepancies of more than 35% are found from one location to another, showing that the same compression garment cannot be applied for treating deficiencies of the deep venous system or deficiencies of the large superficial veins. Moreover, it is shown that the internal morphology of the human leg plays an important role. Accordingly, the approach presented in this paper may provide useful information for adapting compression garments to the specificity of each patient.

. Influence of the stitching density on the transverse permeability of Non-Crimped New Concept (NC2) multiaxial reinforcements : measurements and predictions. Composites Science and Technology, Elsevier, 2002, 62 (15), pp.1979. <10.1016 AbstractNew manufacturing processes arise for polymer-based composites which involve resin infusion through dry pre-forms. Modelling approaches of these processes require to assess new physical characteristics of the materials. In this paper, the transverse permeability of new multiaxial stitched materials, referred to as NC2, is investigated. First, in the framework of Darcy's flows, this permeability is assessed for various biaxial NC2 using a specific device. Through this approach it is shown that the transverse permeability depends strongly on the stitching density. Then, the results from a simplified FE study carried out at the blanket scale are shown to correlate quite well the experimental measurements and evidences established in the first part.

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