Simulating intersection angles between conjugate faults in sea ice with different viscous–plastic rheologies

Recent high-resolution pan-Arctic sea ice simulations show fracture patterns (linear kinematic features or LKFs) that are typical of granular materials but with wider fracture angles than those observed in high-resolution satellite images. Motivated by this, ice fracture is investigated in a simple...

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Published in:The Cryosphere
Main Authors: Ringeisen, Damien, Losch, Martin, Tremblay, L. Bruno, Hutter, Nils
Format: Text
Language:English
Published: 2019
Subjects:
Online Access:https://doi.org/10.5194/tc-13-1167-2019
https://tc.copernicus.org/articles/13/1167/2019/
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spelling ftcopernicus:oai:publications.copernicus.org:tc71221 2023-05-15T15:19:06+02:00 Simulating intersection angles between conjugate faults in sea ice with different viscous–plastic rheologies Ringeisen, Damien Losch, Martin Tremblay, L. Bruno Hutter, Nils 2019-04-09 application/pdf https://doi.org/10.5194/tc-13-1167-2019 https://tc.copernicus.org/articles/13/1167/2019/ eng eng doi:10.5194/tc-13-1167-2019 https://tc.copernicus.org/articles/13/1167/2019/ eISSN: 1994-0424 Text 2019 ftcopernicus https://doi.org/10.5194/tc-13-1167-2019 2020-07-20T16:22:53Z Recent high-resolution pan-Arctic sea ice simulations show fracture patterns (linear kinematic features or LKFs) that are typical of granular materials but with wider fracture angles than those observed in high-resolution satellite images. Motivated by this, ice fracture is investigated in a simple uni-axial loading test using two different viscous–plastic (VP) rheologies: one with an elliptical yield curve and a normal flow rule and one with a Coulombic yield curve and a normal flow rule that applies only to the elliptical cap. With the standard VP rheology, it is not possible to simulate fracture angles smaller than 30 ∘ . Further, the standard VP model is not consistent with the behavior of granular material such as sea ice because (1) the fracture angle increases with ice shear strength; (2) the divergence along the fracture lines (or LKFs) is uniquely defined by the shear strength of the material with divergence for high shear strength and convergent with low shear strength; (3) the angle of fracture depends on the confining pressure with more convergence as the confining pressure increases. This behavior of the VP model is connected to the convexity of the yield curve together with use of a normal flow rule. In the Coulombic model, the angle of fracture is smaller ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi mathvariant="italic">θ</mi><mo>=</mo><mn mathvariant="normal">23</mn><msup><mi/><mo>∘</mo></msup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="38pt" height="11pt" class="svg-formula" dspmath="mathimg" md5hash="4ce44c981e6549817727c7ca362d1318"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-13-1167-2019-ie00001.svg" width="38pt" height="11pt" src="tc-13-1167-2019-ie00001.png"/></svg:svg> ) and grossly consistent with observations. The solution, however, is unstable when the compressive stress is too large because of non-differentiable corners between the straight limbs of the Coulombic yield curve and the elliptical cap. The results suggest that, although at first sight the large-scale patterns of LKFs simulated with a VP sea ice model appear to be realistic, the elliptical yield curve with a normal flow rule is not consistent with the notion of sea ice as a pressure-sensitive and dilatant granular material. Text Arctic Sea ice Copernicus Publications: E-Journals Arctic The Cryosphere 13 4 1167 1186
institution Open Polar
collection Copernicus Publications: E-Journals
op_collection_id ftcopernicus
language English
description Recent high-resolution pan-Arctic sea ice simulations show fracture patterns (linear kinematic features or LKFs) that are typical of granular materials but with wider fracture angles than those observed in high-resolution satellite images. Motivated by this, ice fracture is investigated in a simple uni-axial loading test using two different viscous–plastic (VP) rheologies: one with an elliptical yield curve and a normal flow rule and one with a Coulombic yield curve and a normal flow rule that applies only to the elliptical cap. With the standard VP rheology, it is not possible to simulate fracture angles smaller than 30 ∘ . Further, the standard VP model is not consistent with the behavior of granular material such as sea ice because (1) the fracture angle increases with ice shear strength; (2) the divergence along the fracture lines (or LKFs) is uniquely defined by the shear strength of the material with divergence for high shear strength and convergent with low shear strength; (3) the angle of fracture depends on the confining pressure with more convergence as the confining pressure increases. This behavior of the VP model is connected to the convexity of the yield curve together with use of a normal flow rule. In the Coulombic model, the angle of fracture is smaller ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi mathvariant="italic">θ</mi><mo>=</mo><mn mathvariant="normal">23</mn><msup><mi/><mo>∘</mo></msup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="38pt" height="11pt" class="svg-formula" dspmath="mathimg" md5hash="4ce44c981e6549817727c7ca362d1318"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-13-1167-2019-ie00001.svg" width="38pt" height="11pt" src="tc-13-1167-2019-ie00001.png"/></svg:svg> ) and grossly consistent with observations. The solution, however, is unstable when the compressive stress is too large because of non-differentiable corners between the straight limbs of the Coulombic yield curve and the elliptical cap. The results suggest that, although at first sight the large-scale patterns of LKFs simulated with a VP sea ice model appear to be realistic, the elliptical yield curve with a normal flow rule is not consistent with the notion of sea ice as a pressure-sensitive and dilatant granular material.
format Text
author Ringeisen, Damien
Losch, Martin
Tremblay, L. Bruno
Hutter, Nils
spellingShingle Ringeisen, Damien
Losch, Martin
Tremblay, L. Bruno
Hutter, Nils
Simulating intersection angles between conjugate faults in sea ice with different viscous–plastic rheologies
author_facet Ringeisen, Damien
Losch, Martin
Tremblay, L. Bruno
Hutter, Nils
author_sort Ringeisen, Damien
title Simulating intersection angles between conjugate faults in sea ice with different viscous–plastic rheologies
title_short Simulating intersection angles between conjugate faults in sea ice with different viscous–plastic rheologies
title_full Simulating intersection angles between conjugate faults in sea ice with different viscous–plastic rheologies
title_fullStr Simulating intersection angles between conjugate faults in sea ice with different viscous–plastic rheologies
title_full_unstemmed Simulating intersection angles between conjugate faults in sea ice with different viscous–plastic rheologies
title_sort simulating intersection angles between conjugate faults in sea ice with different viscous–plastic rheologies
publishDate 2019
url https://doi.org/10.5194/tc-13-1167-2019
https://tc.copernicus.org/articles/13/1167/2019/
geographic Arctic
geographic_facet Arctic
genre Arctic
Sea ice
genre_facet Arctic
Sea ice
op_source eISSN: 1994-0424
op_relation doi:10.5194/tc-13-1167-2019
https://tc.copernicus.org/articles/13/1167/2019/
op_doi https://doi.org/10.5194/tc-13-1167-2019
container_title The Cryosphere
container_volume 13
container_issue 4
container_start_page 1167
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