Athermal rheology of weakly attractive soft particles

Ehsan Irani, Pinaki Chaudhuri, and Claus Heussinger
Phys. Rev. E 94, 052608 – Published 28 November 2016

Abstract

We study the rheology of a soft particulate system where the interparticle interactions are weakly attractive. Using extensive molecular dynamics simulations, we scan across a wide range of packing fractions (ϕ), attraction strengths (u), and imposed shear rates (γ̇). In striking contrast to repulsive systems, we find that at small shear rates generically a fragile isostatic solid is formed even if we go to ϕϕJ. Further, with increasing shear rates, even at these low ϕ, nonmonotonic flow curves occur which lead to the formation of persistent shear bands in large enough systems. By tuning the damping parameter, we also show that inertia plays an important role in this process. Furthermore, we observe enhanced particle dynamics in the attraction-dominated regime as well as a pronounced anisotropy of velocity and diffusion constant, which we take as precursors to the formation of shear bands. At low enough ϕ, we also observe structural changes via the interplay of low shear rates and attraction with the formation of microclusters and voids. Finally, we characterize the properties of the emergent shear bands, and thereby, we find surprisingly small mobility of these bands, leading to prohibitively long time scales and extensive history effects in ramping experiments.

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  • Received 4 May 2016

DOI:https://doi.org/10.1103/PhysRevE.94.052608

©2016 American Physical Society

Physics Subject Headings (PhySH)

Polymers & Soft Matter

Authors & Affiliations

Ehsan Irani1, Pinaki Chaudhuri2, and Claus Heussinger1

  • 1Institute for Theoretical Physics, Georg-August University of Göttingen, Friedrich-Hund Platz 1, 37077 Göttingen, Germany
  • 2Institute of Mathematical Sciences, Taramani, Chennai 600 113, Tamil Nadu, India

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Issue

Vol. 94, Iss. 5 — November 2016

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