Dynamics of the Ice-Crushing Process
Abstract During fast indentation tests on ice sheets at constant rates, crushing is commonly observed at appropriate combinations of speed and aspect ratio. An analysis is made of this mode of failure, using as a basis a recently conducted test on an ice sheet under controlled conditions. The variat...
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Language: | English |
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Cambridge University Press (CUP)
1988
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Online Access: | http://dx.doi.org/10.1017/s0022143000007085 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000007085 |
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crcambridgeupr:10.1017/s0022143000007085 2024-03-03T08:45:25+00:00 Dynamics of the Ice-Crushing Process Jordaan, Ian J. Timco, Garry W. 1988 http://dx.doi.org/10.1017/s0022143000007085 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000007085 en eng Cambridge University Press (CUP) Journal of Glaciology volume 34, issue 118, page 318-326 ISSN 0022-1430 1727-5652 Earth-Surface Processes journal-article 1988 crcambridgeupr https://doi.org/10.1017/s0022143000007085 2024-02-08T08:34:04Z Abstract During fast indentation tests on ice sheets at constant rates, crushing is commonly observed at appropriate combinations of speed and aspect ratio. An analysis is made of this mode of failure, using as a basis a recently conducted test on an ice sheet under controlled conditions. The variation of load with time is given special attention, and cyclic variation of load is associated with periodic crushing (pulverization) events, followed by clearing of the crushed ice particles. An analysis of the clearing process is summarized in the paper, treating the crushed ice as a viscous material. A detailed analysis of the energy exchanges during the indentation process is given. Elastic variations of stored energy in the indenter and in the ice sheet are calculated; these are relatively minor. The dissipation of energy during a typical load cycle (3 mm movement during 0.05 s) is about 8 J. The energy required to create surfaces of the crushed ice particles is small (0.006 J), as is the work of crushing based on mechanical testing (0.09 J). It is concluded that the process of viscous extrusion of crushed ice is the main seat of energy dissipation, basically as a frictional process. A relationship for the mean thickness of the crushed ice layer is developed, based on energy-balance considerations. Article in Journal/Newspaper Ice Sheet Journal of Glaciology Cambridge University Press Journal of Glaciology 34 118 318 326 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
topic |
Earth-Surface Processes |
spellingShingle |
Earth-Surface Processes Jordaan, Ian J. Timco, Garry W. Dynamics of the Ice-Crushing Process |
topic_facet |
Earth-Surface Processes |
description |
Abstract During fast indentation tests on ice sheets at constant rates, crushing is commonly observed at appropriate combinations of speed and aspect ratio. An analysis is made of this mode of failure, using as a basis a recently conducted test on an ice sheet under controlled conditions. The variation of load with time is given special attention, and cyclic variation of load is associated with periodic crushing (pulverization) events, followed by clearing of the crushed ice particles. An analysis of the clearing process is summarized in the paper, treating the crushed ice as a viscous material. A detailed analysis of the energy exchanges during the indentation process is given. Elastic variations of stored energy in the indenter and in the ice sheet are calculated; these are relatively minor. The dissipation of energy during a typical load cycle (3 mm movement during 0.05 s) is about 8 J. The energy required to create surfaces of the crushed ice particles is small (0.006 J), as is the work of crushing based on mechanical testing (0.09 J). It is concluded that the process of viscous extrusion of crushed ice is the main seat of energy dissipation, basically as a frictional process. A relationship for the mean thickness of the crushed ice layer is developed, based on energy-balance considerations. |
format |
Article in Journal/Newspaper |
author |
Jordaan, Ian J. Timco, Garry W. |
author_facet |
Jordaan, Ian J. Timco, Garry W. |
author_sort |
Jordaan, Ian J. |
title |
Dynamics of the Ice-Crushing Process |
title_short |
Dynamics of the Ice-Crushing Process |
title_full |
Dynamics of the Ice-Crushing Process |
title_fullStr |
Dynamics of the Ice-Crushing Process |
title_full_unstemmed |
Dynamics of the Ice-Crushing Process |
title_sort |
dynamics of the ice-crushing process |
publisher |
Cambridge University Press (CUP) |
publishDate |
1988 |
url |
http://dx.doi.org/10.1017/s0022143000007085 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000007085 |
genre |
Ice Sheet Journal of Glaciology |
genre_facet |
Ice Sheet Journal of Glaciology |
op_source |
Journal of Glaciology volume 34, issue 118, page 318-326 ISSN 0022-1430 1727-5652 |
op_doi |
https://doi.org/10.1017/s0022143000007085 |
container_title |
Journal of Glaciology |
container_volume |
34 |
container_issue |
118 |
container_start_page |
318 |
op_container_end_page |
326 |
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1792500978780471296 |