Constitutive relations for the shear band evolution in granular matter under large strain--颗粒学报PARTICUOLOGY

Luding, S. (2008). Constitutive relations for the shear band evolution in granular matter under large strain. Particuology, 6(6), 501–505. https://doi.org/10.1016/j.partic.2008.07.020

Constitutive relations for the shear band evolution in granular matter under large strain

Stefan Luding^*

Multi Scale Mechanics, TS, CTW, UTwente, P.O. Box 217, 7500 AE Enschede, Netherlands

10.1016/j.partic.2008.07.020

Volume 6, Issue 6, December 2008, Pages 501-505

Received 31 May 2007, Accepted 15 July 2008, Available online 18 November 2008.

E-mail: s.luding@utwente.nl

Highlights

Abstract

A so-called “split-bottom ring shear cell” leads to wide shear bands under slow, quasi-static deformation. Unlike normal cylindrical Couette shear cells or rheometers, the bottom plate is split such that the outer part of it can move with the outer wall, while the other part (inner disk) is immobile. From discrete element simulations (DEM), several continuum fields like the density, velocity, deformation gradient and stress are computed and evaluated with the goal to formulate objective constitutive relations for the powder flow behavior. From a single simulation, by applying time- and (local) space-averaging, a non-linear yield surface is obtained with peculiar stress dependence.

The anisotropy is always smaller than the macroscopic friction coefficient. However, the lower bound of anisotropy increases with the strain rate, approaching the maximum according to a stretched exponential with a specific rate that is consistent with a shear path of about one particle diameter.

Graphical abstract

Keywords

Ring shear cell; Shear bands; DEM simulation; Micro–macro transition; Objective constitutive relations; Yield stress fluid

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