Shear-induced organization of forces in dense suspensions: signatures of discontinuous shear thickening

¹ Physics of Living Systems, MIT, 400 Technology Square, Cambridge, MA 02139, USA
² Martin Fisher School of Physics, Brandeis University, Waltham, MA 02454, USA
³ Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Cambridge CB3 0WA, UK
⁴ Benjamin Levich Institute, City College of New York, New York, NY 10031, USA
⁵ Department of Chemical Engineering, City College of New York, New York, NY 10031, USA

^* e-mail: sumantra@mit.edu
^** e-mail: bulbul@brandeis.edu

Published online: 30 June 2017

Abstract

Dense suspensions can exhibit an abrupt change in their viscosity in response to increasing shear rate. The origin of this discontinuous shear thickening (DST) has been ascribed to the transformation of lubricated contacts to frictional, particle-on-particle contacts. Recent research on the flowing and jamming behavior of dense suspensions has explored the intersection of ideas from granular physics and Stokesian fluid dynamics to better understand this transition from lubricated to frictional rheology. DST is reminiscent of classical phase transitions, and a key question is how interactions between the microscopic constituents give rise to a macroscopic transition. In this paper, we extend a formalism that has proven to be successful in understanding shear jamming of dry grains to dense suspensions. Quantitative analysis of the collective evolution of the contactforce network accompanying the DST transition demonstrates clear changes in the distribution of microscopic variables, and leads to the identification of an “order parameter” characterizing DST.