Anelastic Behaviour of Polycrystalline Ice
Abstract Torsion creep tests were performed on glacier ice at temperatures above -12°C. The polycrystalline ice, when unloaded, exhibits creep recovery. The time-dependent recoverable component of deformation (or anelastic strain) ϵ a was found to be adequately described by a relationship of the for...
| Published in: | Journal of Glaciology |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
1978
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1017/s0022143000033736 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000033736 |
| Summary: | Abstract Torsion creep tests were performed on glacier ice at temperatures above -12°C. The polycrystalline ice, when unloaded, exhibits creep recovery. The time-dependent recoverable component of deformation (or anelastic strain) ϵ a was found to be adequately described by a relationship of the form: ϵ a = Δτ log(r + α t )/ h , where Δτ is the stress decrement, α a constant, and t the time. The anelastic modulus h defined for times t in excess of 3 h is always smaller than the dynamic elastic modulus. The movement of dislocations composing the sub-boundaries or in dislocation pile-ups may produce this important reversible deformation. The time-dependent recovery is explained in a similar way to the transient creep behaviour observed at low temperatures for metals. The small temperature dependence of creep recovery would arise from the existence of a distribution of internal stresses values. |
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