Spanning the scales of granular materials through microscopic force imaging.
If you walk on sand, it supports your weight. How do the disordered forces between particles in sand organize, to keep you from sinking? This simple question is surprisingly difficult to answer experimentally: measuring forces in three dimensions, between deeply buried grains, is challenging. Here we describe experiments in which we have succeeded in measuring forces inside a granular packing subject to controlled deformations. We connect the measured micro-scale forces to the macro-scale packing force response with an averaging, mean field calculation. This calculation explains how the combination of packing structure and contact deformations produce the observed nontrivial mechanical response of the packing, revealing a surprising microscopic particle deformation enhancement mechanism.
1] Department of Physics, Duke University, Physics Building, Science Drive, Box 90305, Durham, North Carolina 27708, USA [2] Institut National de Recherche en Informatique et en Automatique, Bordeaux Sud-Ouest, 200 avenue de la Vieille Tour, 33405 Talence, France.
Nicolas
N
Brodu
1] Department of Physics, Duke University, Physics Building, Science Drive, Box 90305, Durham, North Carolina 27708, USA [2] Laboratory of Physical Chemistry and Colloid Science, Wageningen University, PO Box 8038, 6700EK Wageningen, The Netherlands.
Joshua A
JA
Dijksman
Department of Physics, Duke University, Physics Building, Science Drive, Box 90305, Durham, North Carolina 27708, USA.
Robert P
RP
Behringer