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Theses

Étude et modélisation de l'orientation de fibres dans des thermoplastiques renforcés

Abstract : This thesis is devoted to the study and the modelling of long glass fiber in thermoplastic reinforced component. In order to understand the behaviour of long glass fiber composite, we propose in this work to study the orientation phenomena and the rheology of these suspensions. With an experimental approach, one has characterized fiber orientations and arrangements in a thermoplastic component. Fiber length distribution analysis has shown that fiber breakage was done mainly during plastification process. Orientation measurements, performed with 2D and 3D procedures show that fiber concentration is a key parameter driven the skin-core structure. We propose a numerical tool to compute directly the motion of dense population of fibers in a flow by using a multidomain approach and finite element method (thanks to Rem3D software). The main novelty of this approach is that the particules-fluid interaction are directly taken into account and it is not necessary to express explicitly short and large range hydrodynamic forces. Direct numerical computations with a large number of fibers are performed and give macroscopic informations on fiber suspensions. In this way, one can determine the evolution of Folgar & Tucker diffusion constant, Ci, and check the validity of closure approximation in a Newtonian shear flow: the Ci coefficient is a function of the aspect ratio and the fiber concentration; the hybrid closure approximation gives the best approximation of fourth order orientation tensor. Finally, this approach is applied to analyse rheological properties of fiber suspensions.
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https://pastel.archives-ouvertes.fr/pastel-00001471
Contributor : Ecole Mines Paristech <>
Submitted on : Monday, November 21, 2005 - 8:00:00 AM
Last modification on : Thursday, September 24, 2020 - 5:22:54 PM
Long-term archiving on: : Thursday, September 30, 2010 - 7:01:55 PM

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  • HAL Id : pastel-00001471, version 1

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Alexandra Megally. Étude et modélisation de l'orientation de fibres dans des thermoplastiques renforcés. Sciences de l'ingénieur [physics]. École Nationale Supérieure des Mines de Paris, 2005. Français. ⟨pastel-00001471⟩

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