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Title: Stress distributions in flowing aggregated colloidal suspensions

Abstract

Simulations of the flow of concentrated aggregated colloidal systems, at the particulate level, are used to investigate the distribution of stresses in the shear-thinning regime. It is found that the distribution of shear stress carried by interparticle bonds decays approximately exponentially at large stresses, but with a double-exponential distribution for values of positive stress. The microstructural mechanisms associated with large stresses are manifested in clusters which dominate the positive contribution to the stress in the system. Towards the end of shear thinning the highest forces occur along bonds defining rods of particles aligned approximately along the flow-compression direction. We propose that the rheology of such systems is determined by a rupture{endash}reformation process of these clusters of stress concentration during the flow. The aggregation forces play the role of enhancing such stress concentration by stabilizing clusters against buckling. {copyright} {ital 1999 American Institute of Physics.}

Authors:
 [1];  [2];  [3];  [4]
  1. Advanced Materials Laboratory, Sandia National Laboratories, Albuquerque, New Mexico 87185-1349 (United States)
  2. Unilever Research, Colworth House, Sharnbrook, Bedford, MK44 11Q (United Kingdom)
  3. Polymers and Colloids Group, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE (United Kingdom)
  4. Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom)
Publication Date:
OSTI Identifier:
362674
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 111; Journal Issue: 10; Other Information: PBD: Sep 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AGGLOMERATION; FLOW STRESS; COLLOIDS; SUSPENSIONS; SIMULATION; RHEOLOGY; SHEAR

Citation Formats

Silbert, L.E., Farr, R.S., Melrose, J.R., and Ball, R.C. Stress distributions in flowing aggregated colloidal suspensions. United States: N. p., 1999. Web. doi:10.1063/1.479241.
Silbert, L.E., Farr, R.S., Melrose, J.R., & Ball, R.C. Stress distributions in flowing aggregated colloidal suspensions. United States. doi:10.1063/1.479241.
Silbert, L.E., Farr, R.S., Melrose, J.R., and Ball, R.C. Wed . "Stress distributions in flowing aggregated colloidal suspensions". United States. doi:10.1063/1.479241.
@article{osti_362674,
title = {Stress distributions in flowing aggregated colloidal suspensions},
author = {Silbert, L.E. and Farr, R.S. and Melrose, J.R. and Ball, R.C.},
abstractNote = {Simulations of the flow of concentrated aggregated colloidal systems, at the particulate level, are used to investigate the distribution of stresses in the shear-thinning regime. It is found that the distribution of shear stress carried by interparticle bonds decays approximately exponentially at large stresses, but with a double-exponential distribution for values of positive stress. The microstructural mechanisms associated with large stresses are manifested in clusters which dominate the positive contribution to the stress in the system. Towards the end of shear thinning the highest forces occur along bonds defining rods of particles aligned approximately along the flow-compression direction. We propose that the rheology of such systems is determined by a rupture{endash}reformation process of these clusters of stress concentration during the flow. The aggregation forces play the role of enhancing such stress concentration by stabilizing clusters against buckling. {copyright} {ital 1999 American Institute of Physics.}},
doi = {10.1063/1.479241},
journal = {Journal of Chemical Physics},
number = 10,
volume = 111,
place = {United States},
year = {1999},
month = {9}
}