Paper number 604


Y. Henzel1,2 , J. Bréard2 , D. Lang1 and F. Trochu2

1Aérospatiale, Centre Commun de Recherche Louis Blériot 12 rue Pasteur, BP 76, 92151 Suresnes Cedex, France
2École Polytechnique de Montréal, Département de Génie Mécanique C.P. 6079, Succ. Centre-Ville, Montréal (Québec) H3C 3A7, Canada

Summary A large number of investigations on permeability measurement in fibre reinforcements have been done to establish the behaviour of the macroscopic flow through a porous medium. However, these measurements often depend on large uncertainties related to material heterogeneity, and experimental artefacts that are not easy to control. In most cases, the different measurement techniques used lead to results that are very method-dependent. Thus, a new approach is suggested here to characterise the morphological granulometry of composite samples, in direct relation with a complete description of the macroscopic momentum equation of the fluid phase. The permeability of a porous medium depends on many parameters such as porosity, tortuosity, and the shape factor of a specific section. These parameters describe the geometrical configuration of the void space. The permeability is an intrinsic characteristic of the reinforcement material and does not change with the characteristics of the fluid, although several scales of drag flow should be considered. Our micro-structural approach integrates the local geometrical characteristics of the reinforcement into the global properties. The difference of results between saturated and unsaturated flow conditions is clarified through a description of the saturation degree in the porous medium. These analyses are also compared with structural and phenomenological approaches.
Keywords porous media, permeability, saturated-unsaturated, macro-micro, deformable, image processing, connexity, morphology.

Theme : Processing, Integrated Design and Manufacturing

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