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Contribution à l’étude des instabilités plastiques et de la localisation : aspects macroscopiques et mésoscopiques

Abstract : The localization of plastic deformation in metallic shells under dynamic expansion, which is at the origin of their fragmentation, is initiated by physical processes taking place at different scales, from the one of the crystal lattice to the one of the whole structure. This has been the main topic of my research during the last fifteen years. The sensitivity of localization conditions to the tridimensional macroscopic behavior was investigated with the help of stability analysis. On the contrary, at the microscale, crystal plasticity models simulate plastic slip and the effect of dislocation interactions; in particular conditions they are able to predict localization processes developing inside grains. A non-local extension of such models including geometrically necessary dislocations (GND) was next considered: the existence of a characteristic length for the former localization patterns was then justified. At the scale of a shell element, the polycrystalline structure was inserted in computations performed with a crystal plasticity FE code: the connection between the grain scale strain organization and the onset of macroscopic localization was found to depend on the grain size and on the stretching rate.
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Contributor : Jean-Lin Dequiedt Connect in order to contact the contributor
Submitted on : Tuesday, July 6, 2021 - 1:32:22 PM
Last modification on : Friday, August 5, 2022 - 2:54:00 PM
Long-term archiving on: : Thursday, October 7, 2021 - 6:37:24 PM


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  • HAL Id : tel-03279249, version 1


Jean-Lin Dequiedt. Contribution à l’étude des instabilités plastiques et de la localisation : aspects macroscopiques et mésoscopiques. Mécanique des matériaux [physics.class-ph]. Université de Lorraine, 2021. ⟨tel-03279249⟩



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