Mechanical Properties of Acoustically Levitated Granular Rafts

Melody X. Lim, Bryan VanSaders, Anton Souslov, Heinrich M. Jaeger

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6 Citations (SciVal)


We investigate a model system for the rotational dynamics of inertial many-particle clustering, in which submillimeter objects are acoustically levitated in air. Driven by scattered sound, levitated grains self-assemble into a monolayer of particles, forming mesoscopic granular rafts with both an acoustic binding energy and a bending rigidity. Detuning the acoustic trap can give rise to stochastic forces and torques that impart angular momentum to levitated objects. As the angular momentum of a quasi-two-dimensional granular raft is increased, the raft deforms from a disk to an ellipse, eventually pinching off into multiple separate rafts, in a mechanism that resembles the breakup of a liquid drop. We extract the raft effective surface tension and elastic modulus and show that nonpairwise acoustic forces give rise to effective elastic moduli that scale with the raft size. We also show that the raft size controls the microstructural basis of plastic deformation, resulting in a transition from fracture to ductile failure.
Original languageEnglish
Article number021017
JournalPhysical Review X
Issue number2
Publication statusPublished - 22 Apr 2022

Bibliographical note

We thank David Grier, Grayson Jackson, Tali Khain, Adam Kline, Vincenzo Vitelli, and Tom Witten for useful and inspiring discussions. This research was supported by the National Science Foundation through Grants No. DMR-1810390 and No. DMR-2104733. This work utilized the shared experimental facilities at the University of Chicago MRSEC, which is funded by the National Science Foundation under Grant No. DMR-2011854. This research utilized computational resources and services supported by the Research Computing Center at the University of Chicago. A. S. gratefully acknowledges the support of the Engineering and Physical Sciences Research Council (EPSRC) through New Investigator Grant No. EP/T000961/1.

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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