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Contribution à la caractérisation et à la modélisation du micro-écaillage de l'étain fondu sous choc

Abstract : When a material is subjected to an unsupported shock wave sufficiently intense to induce melting, tensile stresses produced upon reflection of this wave on a free surface are generated in a liquid state. As a consequence, a dynamic fragmentation process called micro-spalling occurs, leading to the creation of a cloud of fine droplets. This thesis aims at providing a better understanding of this phenomenon in order to develop a physical modelling. Experimental investigation, including plate impacts and laser-driven shocks on tin, provides fundamental data concerning the micro-spalling process. Theoretical and numerical analysis of existing fragmentation models based on global energetic approach leads to the formulation of a fragmentation criterion appropriate for micro-spalling that is implemented in a hydrocode. Computations provide a first description of the droplets cloud in terms of size and velocity distributions, as well as information about the state of the liquid and its evolution. In parallel, a second modelling approach aims at identifying the physical mechanisms responsible for fragmentation during the micro-spalling process. Cavitation, observed experimentally, is described by means of a hollow sphere model that allows defining the conditions for which the growth of micro-voids can lead to fragmentation in liquid metals. Quantitative results strengthen some predictions of the former fragmentation model based on energetic approach.
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https://tel.archives-ouvertes.fr/tel-00334320
Contributor : Loic Signor <>
Submitted on : Friday, October 24, 2008 - 7:46:15 PM
Last modification on : Monday, October 19, 2020 - 10:57:34 AM
Long-term archiving on: : Tuesday, October 9, 2012 - 2:25:10 PM

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  • HAL Id : tel-00334320, version 1

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Loïc Signor. Contribution à la caractérisation et à la modélisation du micro-écaillage de l'étain fondu sous choc. Mécanique [physics.med-ph]. ISAE-ENSMA Ecole Nationale Supérieure de Mécanique et d'Aérotechique - Poitiers, 2008. Français. ⟨tel-00334320⟩

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