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

作     者：Stefan Luding 

作者机构：Multi Scale Mechanics TS CTW UTwente P.O. Box 217 7500 AE Enschede Netherlands 

出 版 物：《Particuology》 (颗粒学报（英文版）)

年 卷 期：2008年第6卷第6期

页      面：501-505页

核心收录：

学科分类：07[理学] 0817[工学-化学工程与技术] 070205[理学-凝聚态物理] 08[工学] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 0702[理学-物理学] 

基　　金：the Deutsche Forschungsgemeinschaft (DFG) the Stichting voor Fundamenteel Onderzoek der Materie (FOM) supported by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek(NWO) 

主　　题：Ring shear cell Shear bands DEM simulation Micro-macro transition Objective constitutive relations Yield stress fluid 

摘      要：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.