A quadratic viscous fluid law for ice deduced from Steinemann's uni-axial compression and torsion experiments
Abstract The response of ice to applied stress on ice-sheet flow timescales is commonly described by a non-linear incompressible viscous fluid, for which the deviatoric stress has a quadratic relation in the strain rate with two response coefficient functions depending on two principal strain-rate i...
| Published in: | Journal of Glaciology |
|---|---|
| Main Authors: | , |
| Other Authors: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
2021
|
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1017/jog.2021.113 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143021001131 |
| Summary: | Abstract The response of ice to applied stress on ice-sheet flow timescales is commonly described by a non-linear incompressible viscous fluid, for which the deviatoric stress has a quadratic relation in the strain rate with two response coefficient functions depending on two principal strain-rate invariants I 2 and I 3 . Commonly, a coaxial (linear) relation between the deviatoric stress and strain rate, with dependence on one strain-rate invariant I 2 in a stress formulation, equivalently dependence on one deviatoric stress invariant in a strain-rate formulation, is adopted. Glen's uni-axial stress experiments determined such a coaxial law for a strain-rate formulation. The criterion for both uni-axial and shear data to determine the same relation is determined. Here, we apply Steinemann's uni-axial stress and torsion data to determine the two stress response coefficients in a quadratic relation with dependence on a single invariant I 2 . There is a non-negligible quadratic term for some ranges of I 2 that is, a coaxial relation with dependence on one invariant is not valid. The data does not, however, rule out a coaxial relation with dependence on two invariants. |
|---|