Skip to Main content Skip to Navigation
Theses

Contribution à l'étude du comportement viscoplastique des glaces des calottes polaires : modes de déformation et simulation du développement des textures

Abstract : The deformation of ice in polar ice sheets implies strain rates lower than 10e-10s-1. The rheology of polar ice is governed by intracrystalline slip and is associated with the occurence of grain growth and dynamic recrystallization. The stress exponent of the secondary creep is lower than 2. A deformation model based on equilibrium between work hardenning and recovery in ice sheet is developed. Hard X-ray diffraction experiments are performed on ice monocrystals taken along the deep Vostok core (Antarctica). The measured lattice distortion can be described by basal geometrically necessary dislocations of screw and edge type. Deformation modes of polar ice are determined by taking into account the mechanical behavior and the arrangement of dislocations. The simulation of the texture development is performed by using the Visco-Plastic Self Consistent (VPSC) "1-site" model developed by Lebensohn and Tomé (1993). This model is modified to take into account the anisotropy of the ice monocrystal, and polar ice deformation conditions. A good estimation of texture development along the Vostok and GRIP ice core is obtained. Expansion of the model to introduce rotation recrystallization does not point out the influence of associated mechanisms on texture development. Finally, a "n-sites" type of modelling using Fast Fourier Transform (Lebensohn 2001) is investigated to simulate the heterogeneities within crystals and improve the calculation of grain interactions.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00010695
Contributor : Maurine Montagnat-Rentier <>
Submitted on : Thursday, October 20, 2005 - 10:08:26 AM
Last modification on : Friday, December 4, 2020 - 11:20:05 AM
Long-term archiving on: : Friday, April 2, 2010 - 10:49:14 PM

Identifiers

  • HAL Id : tel-00010695, version 1

Collections

Citation

Maurine Montagnat. Contribution à l'étude du comportement viscoplastique des glaces des calottes polaires : modes de déformation et simulation du développement des textures. Mécanique [physics.med-ph]. Université Joseph-Fourier - Grenoble I, 2001. Français. ⟨tel-00010695⟩

Share

Metrics

Record views

282

Files downloads

280