Quantifying interparticle forces and heterogeneity in 3D granular materials
Extensive theoretical, numerical, and experimental research has examined interparticle forces in granular materials. Interparticle forces are intimately linked to mechanical properties and are known to self-organize into heterogeneous structures, or force chains, under external load. Despite progress in understanding the statistics and spatial distribution of interparticle forces in recent decades, a systematic method for measuring forces in opaque, 3D, frictional, stiff granular media has yet to emerge. In this Letter, we present results from an experiment that combines 3D X-ray diffraction, X-ray tomography, and a numerical force inference technique to quantify interparticle forces and their heterogeneity in a granular material composed of quartz grains undergoing a 1D compression cycle. Forces exhibit an exponential decay above the mean and partition into strong and weak networks. We find a surprising inverse relationship between macroscopic load and the heterogeneity of interparticle forces, despite the clear emergence of two force chains that span the system.
© 2016 American Physical Society. (Received 11 March 2016; published 24 August 2016) The authors acknowledge the ESRF for synchrotron beam time for proposal ma1913. R. C. H. and J. E. A. acknowledge support from the U.S. Air Force Office of Scientific Research Grant No. FA9550-12-1-0091 and the U.S. Defense Threat Reduction Agency Grant No. HDTRA1-12-1-0041. S. A. H. acknowledges support from a Marie Curie FP7 integration grant within the 7th European Union Framework Programme. Part of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Award No. DE-AC52-07NA27344.
Supplemental Material - PRL_HurleyHallEtAl_Supplement.pdf
Published - PhysRevLett.117.098005.pdf
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