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Titolo:
Strengthening and weakening of induced anisotropy in polar ice
Autore:
Staroszczyk, R; Morland, LW;
Indirizzi:
Polish Acad Sci, Inst Hydroengn, PL-71310 Szczecin, Poland Polish Acad Sci Szczecin Poland PL-71310 engn, PL-71310 Szczecin, Poland Univ E Anglia, Sch Math, Norwich NR4 7TJ, Norfolk, England Univ E Anglia Norwich Norfolk England NR4 7TJ h NR4 7TJ, Norfolk, England
Titolo Testata:
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
fascicolo: 2014, volume: 457, anno: 2001,
pagine: 2419 - 2440
SICI:
1364-5021(20011008)457:2014<2419:SAWOIA>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
VISCOUS RESPONSE; SHEET; FLOW;
Keywords:
polar ice; recrystallization; induced anisotropy; orthotropy; constitutive equations;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
17
Recensione:
Indirizzi per estratti:
Indirizzo: Staroszczyk, R Polish Acad Sci, Inst Hydroengn, Ul Warynskiego 17, PL-71310 Szczecin, Poland Polish Acad Sci Ul Warynskiego 17 Szczecin Poland PL-71310
Citazione:
R. Staroszczyk e L.W. Morland, "Strengthening and weakening of induced anisotropy in polar ice", P ROY SOC A, 457(2014), 2001, pp. 2419-2440

Abstract

Reorientation of individual crystal glide planes as ice is deformed duringits descent from the free surface to depth in an ice sheet creates a fabric and associated anisotropy. A macroscopic description in which the material glide planes are rotated towards planes normal to an axis of compression,and away from planes normal to an axis of extension, has already been applied to derive an associated orthotropic viscous law which expresses the deviatoric stress in terms of the strain rate, strain and three structure tensors based on the principal stretch axes. At high strain rate, or high shearstress, however, with critical magnitudes decreasing as temperature increases, dynamic (migration) recrystallization occurs and leads to loss of fabric strength and return to isotropic response. The orthotropic viscous law is now extended to incorporate this response, specifically to a behaviour inwhich anisotropy weakens continuously over a finite range of shear strain rate before isotropy is restored. Six different constructions are considered, and their associated directional viscosity properties examined, which show that only one construction is consistent. Continuous axial and shearing responses are illustrated for that law, and the shearing response is shown to have an unexpected behaviour. An alternative approach first reformulatesthe original orthotropic. law as an additive decomposition into isotropic and anisotropic parts, and applies the fabric weakening directly to the latter. This formulation is shown to describe consistent and sensible behaviour in all the test simulations.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/09/20 alle ore 07:55:30