TY - JOUR
T1 - Shear flow of assemblies of cohesive granular materials under constant applied normal stress
AU - Aarons, Lee
AU - Sundaresan, Sankaran
N1 - Funding Information:
This work was partially supported by Merck & Co., Inc., an NSF-NIRT grant, and a DOE-UCR grant. We gratefully acknowledge helpful discussions with Professor Pablo G. Debenedetti and Dr. Sung Joon Moon. We are delighted to have the opportunity to contribute to this special issue felicitating Professor Robert Pfeffer.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2008/4/21
Y1 - 2008/4/21
N2 - We have studied plane shear flow of nearly homogeneous assemblies of uniformly sized, spherical, cohesive particles in periodic domains under constant applied normal stress. Our focus has been on (a) exploration of the effect of inter-particle attractive forces on the flow behavior manifested by dense assemblies under constant applied normal stress, and (b) comparison of the rheological characteristics observed under constant-applied normal stress and constant-volume conditions. As a model problem, the cohesion resulting from van der Waals force acting between particles is considered. Simulations were performed for different strengths of cohesion, shear rates, and applied stresses. From each simulation, the volume fraction, shear stress and the average coordination number have been extracted. We find that cohesive assemblies sheared under constant applied normal stress shear differently from those sheared at constant volume only in the dynamic sense, while the time-averaged rheological characteristics are essentially indistinguishable. At constant volume, the fluctuations in shear stress are larger than, but have the same dependence on cohesion as under constant applied normal stress. This study has also exposed a pronounced dependence of the apparent coefficient of friction on particle volume fraction in the quasi-static flow regime.
AB - We have studied plane shear flow of nearly homogeneous assemblies of uniformly sized, spherical, cohesive particles in periodic domains under constant applied normal stress. Our focus has been on (a) exploration of the effect of inter-particle attractive forces on the flow behavior manifested by dense assemblies under constant applied normal stress, and (b) comparison of the rheological characteristics observed under constant-applied normal stress and constant-volume conditions. As a model problem, the cohesion resulting from van der Waals force acting between particles is considered. Simulations were performed for different strengths of cohesion, shear rates, and applied stresses. From each simulation, the volume fraction, shear stress and the average coordination number have been extracted. We find that cohesive assemblies sheared under constant applied normal stress shear differently from those sheared at constant volume only in the dynamic sense, while the time-averaged rheological characteristics are essentially indistinguishable. At constant volume, the fluctuations in shear stress are larger than, but have the same dependence on cohesion as under constant applied normal stress. This study has also exposed a pronounced dependence of the apparent coefficient of friction on particle volume fraction in the quasi-static flow regime.
KW - Cohesion
KW - Constant stress
KW - Discrete element simulation
KW - Flow regime
KW - Shear flow of powders
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U2 - 10.1016/j.powtec.2008.01.016
DO - 10.1016/j.powtec.2008.01.016
M3 - Article
AN - SCOPUS:41549126560
SN - 0032-5910
VL - 183
SP - 340
EP - 355
JO - Powder Technology
JF - Powder Technology
IS - 3
ER -