Dense Suspensions

Steady State Rheology

Concentrated suspensions of particles in a Newtonian solvent often show striking non-Newtonian behaviors. Of particular interest in our group is shear thickening: an increase in suspension viscosity as a function of applied shear. In dense (>30% solids by volume) suspensions, this thickening can result in a discontinuous increase in the viscosity by orders of magnitude at a critical shear rate. This phenomena is of particular interest to dynamically-responsive protective wear applications, and reveals new physics of complex fluid systems. We study steady-state shear thickening, and its relationship to transient shear jamming, in a variety of systems using stress- and strain controlled rheology.

Qin Xu, Sayantan Majumdar, Eric Brown and Heinrich M. Jaeger, “Shear thickening in highly viscous granular suspensions”, Europhysics Letters 107, 68004 (2014)
Eric Brown and Heinrich M. Jaeger, “Shear thickening in concentrated suspensions: phenomenology, mechanisms, and relations to jamming”, Reports on Progress in Physics 77, 046602 (2014).
Eric Brown and Heinrich M. Jaeger, “Dilation and confining stresses in shear thickening of dense suspensions”, J. Rheology 56(4), 875 - 923 (2012).
Eric Brown, Nicole A. Forman, Carlos S. Orellana, Hanjun Zhang, Ben Maynor, Douglas Betts, Joseph M. DeSimone, and Heinrich M. Jaeger, “Generality of shear thickening in suspensions”, Nature Materials 9, 220 - 224 (2010).

Transient Dynamics

Our recent work on transient dynamics and impact of dense suspensions has elucidated connections between the shear jamming of frictional dry grains, and the shear-induced solidification of dense suspensions. Under a variety of conditions, shear-induced bulk flows cause some systems of dense suspensions, such as cornstarch and water, to undergo a reversible transformation to solid-like behavior. These conditions include impact, extension, and standard shear. We employ these findings to develop novel shear jamming systems that provide further insight into this strongly non-linear behavior.

Sayantan Majumdar, Ivo R. Peters, Endao Han, and Heinrich M. Jaeger, “Dynamic shear jamming under extension in dense granular suspensions”, Phys. Rev. E 95, 012603 (2017)
Ivo R. Peters, Sayantan Majumdar, and Heinrich M. Jaeger, “Direct observation of dynamic shear jamming in dense suspensions”, Nature 532, 214–217 (2016). link, more info
Endao Han, Ivo Peters, Heinrch M. Jaeger, "High-speed ultrasound imaging in dense suspensions reveals impact-activated solidification due to dynamic shear jamming" Nature Communications 7, 12243 (2016)
Scott Waitukaitis and Heinrich M. Jaeger, “Impact-activated solidification of dense suspensions via dynamic jamming fronts”, Nature 487, 205-209, (2012)