scholarly journals Comparison of finite-element and homogenization methods for modelling the viscoplastic behaviour of a S2–columnar-ice polycrystal

2000 ◽  
Vol 30 ◽  
pp. 115-120 ◽  
Author(s):  
Jacques Meyssonnier ◽  
Armelle Philip
Keyword(s):  
Finite Element ◽  
Strain Rate ◽  
Transversely Isotropic ◽  
Uniform Strain ◽  
Upper And Lower Bounds ◽  
Uniform Stress ◽  
Consistent Model ◽  
Self Consistent ◽  
Polycrystalline Ice ◽  
Homogenization Methods

AbstractThe main homogenization schemes used to model the behaviour of polycrystalline ice are assessed by studying the particular case of a two-dimensional polycrystal which represents natural S2–columnar ice. The results of the uniform-stress, uniform-strain-rate and one-site self-consistent models are compared to finite-element computations. The comparisons were made using the same model of grain, described as a continuous transversely isotropic medium, in the linear and non-linear cases. The uniform-stress and uniform-strain-rate models provide upper and lower bounds for the macroscopic fluidity which are too far from each other to be useful when a degree of anisotropy relevant to ice is considered. Although the self-consistent model gives a weak representation of the interaction between a grain and its surroundings, due to the strong anisotropy of the ice crystal, the resulting macroscopic behaviour is found to be acceptable when compared to the results from finite-element computations.

The Indentation Elastic Response - Indentation Shape and the Stress Distribution

1994 ◽  
Vol 356 ◽  
Author(s):  
B. C. Hendrix ◽  
Ke-Wei Xu ◽  
Jun-Hai Liu ◽  
Jia-Wen He
Keyword(s):  
Elastic Recovery ◽  
Transversely Isotropic ◽  
Elastic Response ◽  
Consistent Model ◽  
Self Consistent ◽  
Unique Model ◽  
Transversely Isotropic Materials ◽  
Fundamental Value ◽  
Further Development

AbstractThe unloading of an indentation provides information about the shape of the indentation and the elastic properties of the materials. The assumptions of axisymmetry and material isotropy are critically examined, and a model for transversely isotropic materials is compared to measurements on single crystals. The methods used to infer the area of the indentation from the unloading curve are examined. The area is a fundamental value for the determination of hardness, modulus, and other mechanical properties in the so-called nano-indentor and other continuously monitored indentor techniques. The models of elastic recovery which are currently used are found to lack the flexibility to model the parameters which determine indentation depth. If the current self-consistent model is extended to cover the important aspects of the unloading, the area of the indentation is still not determined uniquely. Guidelines for further development of a unique model are suggested.

scholarly journals Simulation of anisotropic ice flow and fabric evolution along the GRIP–GISP2 flowline, central Greenland

2000 ◽  
Vol 30 ◽  
pp. 217-223 ◽  
Author(s):  
Olivier Gagliardini ◽  
Jacques Meyssonnier
Keyword(s):  
Transversely Isotropic ◽  
Stationary Flow ◽  
Orientation Distribution ◽  
Constitutive Law ◽  
Induced Anisotropy ◽  
Uniform Stress ◽  
Polar Ice ◽  
Ice Flow ◽  
Fabric Evolution ◽  
Polycrystalline Ice

AbstractA model for the anisotropic behaviour of polar ice and the evolution of its strain-induced anisotropy is applied to the flowline between GRIP and GISP2. The linear constitutive law for polycrystalline ice is derived from the uniform-stress model under the assumptions of a linear transversely isotropic behaviour of the ice single crystal and of an orthotropic fabric described by a continuous parameterized orientation-distribution function (ODF). The velocities and fabrics obtained for the observed flowline and bedrock geometry assuming stationary flow, are compared to those measured at the ice-sheet surface and down the two boreholes.

Finite element assessment of an affine self–consistent model for hexagonal polycrystals

2017 ◽  
Vol 61 ◽  
pp. 345-356 ◽  
Author(s):  
P. Pilvin ◽  
F. Onimus ◽  
R. Brenner ◽  
S. Pascal ◽  
X. Feaugas ◽  
...  
Keyword(s):  
Finite Element ◽  
Consistent Model ◽  
Self Consistent

Modeling of the Plastic Behavior of Inhomogeneous Media

1984 ◽  
Vol 106 (4) ◽  
pp. 295-298 ◽  
Author(s):  
M. Berveiller ◽  
A. Zaoui
Keyword(s):  
Integral Equation ◽  
Strain Rate ◽  
The Self ◽  
Plastic Strain Rate ◽  
Plastic Behavior ◽  
Consistent Model ◽  
Self Consistent ◽  
Common Framework ◽  
Strain Rate Field ◽  
General Method

The general method which work for the case of linear properties are taken as a pattern for the derivation of the local total strain rate field of an inhomogeneous material (such as a polycrystal, a composite, or multiphase material) submitted to a uniform macroscopic elastic-plastic strain rate; the localization procedure leads to an integral equation, the solution of which is shown to yield the overall behavior. This method allows to locate within a common framework all the classical approaches, namely Taylor’s, Lin’s ones, the self-consistent scheme…and to suggest possible extensions. Some significant results are reported, concerning strain-hardening, yield stress, and texture devolopment of FCC polycrystals, according to simplified, one-site self-consistent model.

THEORY AND SELF-CONSISTENT MODEL OF DUST-DRIVEN WINDS

2002 ◽  
Vol 5 ◽  
pp. 65-65
Author(s):  
S. Liberatore ◽  
J.-P.J. Lafon ◽  
N. Berruyer
Keyword(s):  
Consistent Model ◽  
Self Consistent
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