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| Titel |
FFT simulation of dynamic recrystallization in polar ice |
| VerfasserIn |
Maria-Gema Llorens, Albert Griera, Ilka Weikusat, Paul D. Bons, Jens Roessiger, Lynn Evans, Ricardo Lebensohn |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250097314
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| Publikation (Nr.) |
 EGU/EGU2014-12880.pdf |
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| Zusammenfassung |
| Research on ice flow is a key to understand how climate changes affect polar ice. Numerical
modelling provides a better insight into the mechanics of ice from the microstructure to the
ice sheet scale. The mechanics of polar ice are very sensitive to temperature changes mainly
due to active recrystallization processes, as the material is very close to its melting point. We
present numerical simulations that predict the microstructural evolution of ice polycrystals
during deformation and dynamic recrystallization at large strain, using a full-field
approach.
The crystal plasticity code (Lebensohn, 2001) is used to calculate the response of a
polycrystalline aggregate that deforms by dislocation glide, applying a Fast Fourier
Transform (FFT). The coupling between FFT and the ELLE microstructural evolution
platform allows us to include recrystallization in the aggregate, which is simulated by means
of two main processes: (1) recovery and subgrain rotation, which locally reduces the crystal
misorientation, and (2) grain boundary migration, which is driven by grain boundary
curvature and intra-grain strain energies.
This contribution presents a comparison of numerical simulations under pure and simple
shear conditions up to high strain at different strain rates. The results show a strong effect of
the recrystallization on the final microstructure. Dynamic recrystallization masks the strain
rate and finite strain heterogeneity resulting from the strong slip anisotropy of ice. However,
this strong effect does not significantly modify the single-maximum pattern of c-axes that are
distributed at a low angle to the shortening direction in both pure and simple shear. In both
cases, recrystallization produces larger and more equidimensional grains, with smooth
boundaries.
References:
R. A. Lebensohn. N-site modelling of a 3D viscoplastic polycrystal using Fast Fourier
Transform. 2001. Acta Materialia 49, pp 2723-2737. |
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