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Modélisation du comportement des matériaux granulaires par des approches discrètes et continues

Abstract : The physical properties of granular media find their origin at the local scale of grains contacts. The present study is devoted to the analysis of the influence of these contacts on the global behavior of these class of materials at different scales. We develop, in the first part of the thesis, a continuous media approach which improves the Janssen theory and enables to calculate the stresses in an ensiled granular medium. This approach also allows to represent qualitatively as well as quantitatively the stresses saturation effect in granular silos. In the second part, a modelling of the saturation phenomenon is performed by means of the discrete numerical simulations achieved with the MULTICOR software. We calculate the average stresses which applied at the walls during the unloading of a silo by a granular medium polydisperse. We notice that the result provided by the discrete numerical simulation agree accurately with those of the continuum approach developed in the first part. Another consequence of the existence of privileged contacts between grains is the anisotropy of the granular materials. In the last part, we develop a micro-mechanical approach which permits to model this anisotropy by a fourth order fabric tensor. We propose a general kinematic hypothesis inserted in a homogenization scheme of anisotropic granular media and compared its predictions in isotropic case, to the discrete numerical simulations of the literature. The qualitative trends and the quantitative results are quite satisfactory.
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https://tel.archives-ouvertes.fr/tel-00348876
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Submitted on : Monday, December 22, 2008 - 3:27:21 PM
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Jamila Rahmoun. Modélisation du comportement des matériaux granulaires par des approches discrètes et continues. Sciences de l'ingénieur [physics]. Université des Sciences et Technologie de Lille - Lille I, 2006. Français. ⟨tel-00348876⟩

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