Modelling viscoplastic behavior of anisotropic polycrystalline ice with a self-Consistent approach

Castelnau, Olivier; Canova, G.R.; Lebensohn, Ricardo A.; Duval, Paul

doi:10.1016/s1359-6454(97)00098-0

Cited by 64 publications

(49 citation statements)

References 27 publications

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“…[35] It is also worth noting that the single-crystal rheology identified here is believed to be more reliable than the earlier estimation used by Castelnau et al [1996Castelnau et al [ , 1997Castelnau et al [ , 1998], due to some inconsistencies of the earlier ''tangent'' SC model used in those papers, already pointed out by Masson et al [2000], and partially corrected in the present affine SC model. In particular, the ''tangent'' method was limited to a unique stress sensitivity for all slip systems.…”

Section: Implications For Slip Systemsmentioning

confidence: 64%

“…Deformation is essentially produced by basal slip, which contributes to the total deformation by more than 80% [Castelnau et al, 1997;Lebensohn et al, 2007]. It is worth noting that polycrystalline ice cannot be deformed to large strains by basal slip only.…”

Section: Viscoplastic Behavior Of Polycrystalsmentioning

confidence: 99%

“…In this context, the selfconsistent (SC) scheme, initially proposed to deal with the elasticity of polycrystals [Hershey, 1954;Kröner, 1958Kröner, , 1978Willis, 1981], has been further extended (in different ways) to deal with purely viscoplastic responses. For example, the ''tangent'' extension of the SC scheme [Molinari et al, 1987;Lebensohn and Tomé, 1993] has been applied to describe the viscoplastic anisotropy of polar ices with pronounced LPO by Castelnau et al [1996Castelnau et al [ , 1997Castelnau et al [ , 1998]. …”

Section: Micromechanical Modelingmentioning

confidence: 99%

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Elastoviscoplastic micromechanical modeling of the transient creep of ice

et al. 2008

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[1] A salient feature of the rheology of isotropic polycrystalline ices is the decrease of the strain rate by more than 2 orders of magnitude during transient creep tests to reach a secondary creep regime at a strain which is systematically of $1%. We use a recent (socalled ''affine'') version of the self-consistent mean-field theory to model the elastoviscoplastic behavior of ice. The model aims at bridging scales between the rheology of single grain and the one of polycrystals by evaluating the intergranular interactions. It takes into account the long-term memory effects, which manifests itself by the fact that local stress and strain rate in grains depend on the whole mechanical history of the polycrystal. It is shown that the strong hardening amplitude during the transient creep is entirely explained by the stress redistribution within the specimen, from an almost uniform stress distribution upon instantaneous loading (purely elastic response) to strong interphase and intraphase heterogeneities in the stationary regime (purely viscoplastic response). The experimental hardening kinetic is much too slow to be explained by the same process; it is attributed to the hardening of hard glide slip systems (prismatic slip) in the transient regime. Moreover, the model very well reproduces the permanent creep rate of several highly anisotropic specimens of the Greenland Ice Core Project ice core (pronounced crystallographic textures), when accounting for a single-grain rheology that well matches the experimental one. Our results are consistent with recent findings concerning dislocation dynamics in ice.

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Section: Implications For Slip Systemsmentioning

confidence: 64%

Section: Viscoplastic Behavior Of Polycrystalsmentioning

confidence: 99%

Section: Micromechanical Modelingmentioning

confidence: 99%

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Elastoviscoplastic micromechanical modeling of the transient creep of ice

et al. 2008

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“…Good information about fabric and texture exists from recent ice core studies [Thorsteinsson et al, 1997;Gow et al, 1997]. Resistance to shear on other slip systems (prism 10 " 10 ð Þ 11 " 20 h iand pyramidal 11 " 22 ð Þ 1123 is 20 times, or higher, than on the basal plane slip system [Castelnau et al, 1997]. The fabric development is qualitatively known from thin section and sonic logging measurements.…”

Section: Introductionmentioning

confidence: 99%

Fabric development with nearest‐neighbor interaction and dynamic recrystallization

Þorsteinsson

2002

J. Geophys. Res.

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[1] Polycrystals undergoing ductile deformation develop lattice-preferred orientation (fabric) as a result of intracrystalline slip. A consequence of fabric development is that bulk physical properties become anisotropic. Fabric development and macroscopic deformation are studied by examining three effects: nearest-neighbor interaction (NNI) among crystals, polygonization, and migration recrystallization. The effects of NNI are modeled by arranging the crystals on a three-dimensional cubic grid and assigning six neighbors to each crystal. The ''strength'' of interaction can vary from no interaction (homogeneous stress) to ''strong'' interaction (significant stress redistribution). Increasing the NNI leads to a more homogeneous strain. Fabric varies in both strength and symmetry at a given bulk strain, depending on the strength of NNI. For a prescribed fabric the strain rate increases as the NNI increases. Recrystallization is modeled from energy balance considerations, and polygonization is formulated in terms of stress differences. Both processes require knowledge of dislocation density, which is calculated in the model as a function of crystal strain and grain size, both of which vary with time. Models of fabric development in ice that include NNI lead to more realistic fabric evolution than models with homogeneous stress. However, available data on fabric evolution are inadequate to determine quantitatively the strength of NNI acting in ice.

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“…Molinari et al (1987) first developed the VPSC code to study the plasticity of metals, and Lebensohn and Tome (1993) extended it to rock-forming minerals. The code has been applied to natural minerals such as ice (Castelnau et al, 1996a(Castelnau et al, , 1996bLebensohn et al, 2009), halite (Wenk et al, 1989b;Lebensohn et al, 2003), calcite (Wenk et al, 1987;Lebensohn et al, 1998), quartz (Wenk et al, 1989a) and olivine (Tommasi et al, 1999;Castelnau et al, 2008), where dislocation creep predominates in plastic deformation.…”

Section: Vpsc Modelmentioning

confidence: 99%