Title: Geometry of Force Network in Frictionless Disordered Matter and a Single Grain Model

Author (Talk): Jing Zhou, Univ of Mass Amherst

Abstract:

We had studied the contact force inside three-dimensional emulsion droplet piles. The chain-like structures of large contact forces were found in this frictionless disordered system. We focused the geometric characteristics of the network of large forces, defined a new correlation function which incorporates both force magnitudes and force orientations, from which a long range correlation was obtained. Follow the geometric aspect of network, we looked at the contact angles between forces on a drop, found the largest two contact forces of a drop tended to be antiparallel (180 degree angle). Therefore, the arising of force chain is not surprising under Newton's third law. A toy model of a single grain was proposed to explain the distributions of contact angles, as well as force distributins. We hope to get some insight from the toy model, though it is way too simple.