Self-organized magnetic particles to tune the mechanical behavior of a granular system
Abstract
© 2016, EPLA.Above a certain density a granular material jams. This property can be
controlled by either tuning a global property, such as the packing fraction or by
applying shear strain, or at the micro-scale by tuning grain shape, inter-particle
friction or externally controlled organization. Here, we introduce a novel way to
change a local granular property by adding a weak anisotropic magnetic interaction
between particles. We measure the evolution of the pressure, P, and coordination number,
Z, for a packing of 2D photo-elastic disks, subject to uniaxial compression. A fraction
R m of the particles have embedded cuboidal magnets. The strength of the magnetic
interactions between particles is too weak to have a strong direct effect on P or
Z when the system is jammed. However, the magnetic interactions play an important
role in the evolution of latent force networks when systems containing a large enough
fraction of the particles with magnets are driven through unjammed to jammed states.
In this case, a statistically stable network of magnetic chains self-organizes before
jamming and overlaps with force chains once jamming occurs, strengthening the granular
medium. This property opens a novel way to control mechanical properties of granular
materials.
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https://hdl.handle.net/10161/10939Published Version (Please cite this version)
10.1209/0295-5075/115/64003Publication Info
Cox, M; Wang, D; Barés, J; & Behringer, RP (2016). Self-organized magnetic particles to tune the mechanical behavior of a granular system.
EPL, 115(6). 10.1209/0295-5075/115/64003. Retrieved from https://hdl.handle.net/10161/10939.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Robert P. Behringer
James B. Duke Professor of Physics
Dr. Behringer's research interests include granular materials: friction, earthquakes,
jamming; nonlinear dynamics; and fluids: Rayleigh-Benard convection, the flow of thin
liquid films, porous media flow, and quantum fluids. His studies focus particularly
on experiments (with some theory/simulation) that yield new insights into the dynamics
and complex behavior of these systems. His experiments involve a number of highly
novel approaches, including the use of photoelasticity for probing granular
This author no longer has a Scholars@Duke profile, so the information shown here reflects
their Duke status at the time this item was deposited.

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