Footprints in sand: the response of a granular material to local perturbations.
We experimentally determine ensemble-averaged responses of granular packings to point forces, and we compare these results to recent models for force propagation in a granular material. We use 2D granular arrays consisting of photoelastic particles: either disks or pentagons, thus spanning the range from ordered to disordered packings. A key finding is that spatial ordering of the particles is a key factor in the force response. Ordered packings have a propagative component that does not occur in disordered packings.
Geng
J
J
Department of Physics and Center for Nonlinear and Complex Systems, Duke University, Durham, North Carolina 27708-0305, USA.
Howell
D
D
Longhi
E
E
Behringer
R P
RP
Reydellet
G
G
Vanel
L
L
Clément
E
E
Luding
S
S