Quantifying Interparticle Forces and Heterogeneity in 3D Granular Materials.
Interparticle forces in granular materials 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, three-dimensional (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 an assembly of quartz grains undergoing a one-dimensional 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.
Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125, USA.
R C
RC
Hurley
Division of Solid Mechanics, Lund University, Lund 22100, Sweden.
S A
SA
Hall
Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125, USA.
J E
JE
Andrade
European Synchrotron Radiation Facility, Grenoble 38000, France.
J
J
Wright