Experimental characterization of the intragranular strain field in columnar ice during transient creepReportar como inadecuado

Experimental characterization of the intragranular strain field in columnar ice during transient creep - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

1 LGGE - Laboratoire de glaciologie et géophysique de l-environnement 2 PIMM - Procédés et Ingénierie en Mécanique et Matériaux Paris 3 SYMME - Laboratoire SYstèmes et Matériaux pour la MEcatronique 4 LMA - Laboratoire de Mécanique et d-Acoustique Marseille

Abstract : A digital image correlation DIC technique has been adapted to polycrystalline ice specimens in order to characterize the develop- ment of strain heterogeneities at an intragranular scale during transient creep deformation compression tests. Specimens exhibit a columnar microstructure so that plastic deformation is essentially two-dimensional, with few in-depth gradients, and therefore surface DIC analyses are representative of the whole specimen volume. Local misorientations at the intragranular scale were also extracted from microstructure analyses carried out with an automatic texture analyzer before and after deformation. Highly localized strain patterns are evidenced by the DIC technique. Local equivalent strain can reach values as much as an order of magnitude larger than the macroscopic average. The structure of the strain pattern does not evolve with strain in the transient creep regime. Almost no correlation between the measured local strain and the Schmid factor of the slip plane of the underlying grain is observed, highlighting the importance of the mechanical interactions between neighboring grains resulting from the very large viscoplastic anisotropy of ice crystals. Finally, the experimental microstructure was introduced in a full-field fast Fourier transform polycrystal model; simulated strain fields are a good match with experimental ones.

Keywords : Elasto-viscoplasticity Polycrystal Creep Strain heterogeneities Digital image correlation

Autor: Fanny Grennerat - Maurine Montagnat - Olivier Castelnau - Pierre Vacher - Hervé Moulinec - Pierre Suquet - P. Duval -

Fuente: https://hal.archives-ouvertes.fr/


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