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Caractérisation mécanique et modélisation numérique du comportement des mousses polymériques sous sollicitations statiques et dynamiques

Abstract : Expanded cellular materials such as polypropylene foams (EPP) are often used in applications of protection and passive safety owing to their great impact energy absorption and the simplicity of implementation. In order to optimize the use of these materials, it is necessary to provide reliable data to numerical computer codes to simulate the behaviour of these materials in particular under conditions of crash loading. Thus, it is essential to characterize in experiments the behaviour of these materials as close as possible to the conditions they can undergo, such as impact loadings, starting with those, which are realistically possible to reproduce in laboratory. Therefore, a compressive vi scholastic Split Hopkinsoll Pressure Bar (SHPB) was developed to reach high strain rates ('" 1500 8-1), and a fly-wheel with a great inertia w"" adapted for intermediate loading velocities ('" 200 8- 1) . The use of these devices have demonstrated the influence of the foam strain rate and density (from 35 to 150 kg. rn-3 ) on the initial collapse stress and the hardening modulus in the post-yield plateau region. Then, these same tests preformed in a fluid chamber highlighted the high contribution of the gas trapped in the closed cells, curing dynamic loading. Finally, a Discrete Element Method (DEM) was developed to model the behaviour of these materials at microscopy scale. This "discrete" approach makes it possible to better understand the phenomena that govern the behaviour of these materials during their compression. First simulation results highlighted the main mechanisms that can lead to high strain localisation during compression and make it possible to quantitatively identify the influence of the microstructure on the behaviour of these materials.
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https://pastel.archives-ouvertes.fr/pastel-00005433
Contributor : Ecole Arts Et Métiers Paristech <>
Submitted on : Tuesday, September 29, 2009 - 8:00:00 AM
Last modification on : Wednesday, November 29, 2017 - 2:56:30 PM
Long-term archiving on: : Friday, September 10, 2010 - 2:32:52 PM

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  • HAL Id : pastel-00005433, version 1

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Rémy Bouix. Caractérisation mécanique et modélisation numérique du comportement des mousses polymériques sous sollicitations statiques et dynamiques. Sciences de l'ingénieur [physics]. Arts et Métiers ParisTech, 2008. Français. ⟨NNT : 2008ENAM0011⟩. ⟨pastel-00005433⟩

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