Comparison of finite-element and homogenization methods for modelling the viscoplastic behaviour of a S2-columnar-ice polycrystal

Author: Meyssonnier Jacques   Philip Armelle  

Publisher: International Glaciological Society

ISSN: 1727-5644

Source: Annals of Glaciology, Vol.30, Iss.1, 2000-01, pp. : 115-120

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Abstract

The main homogenization schemes used to model the behaviour of poly-crystalline ice are assessed by studying the particular case of a two-dimensional poly-crystal which represents natural S2-columnar ice. The results of the uniform-stress, uniform-strain-rate and one-site self-consistent models are compared to finite-element computations. The comparisons were made using the same model of grain, described as a continuous transversely isotropic medium, in the linear and non-linear cases. The uniform-stress and uniform-strain-rate models provide upper and lower bounds for the macroscopic fluidity which are too far from each other to be useful when a degree of anisotropy relevant to ice is considered. Although the self-consistent model gives a weak representation of the interaction between a grain and its surroundings, due to the strong anisotropy of the ice crystal, the resulting macroscopic behaviour is found to be acceptable when compared to the results from finite-element computations.