Origin of Non-cubic Scaling Law in Disordered Granular Packing

TL;DR

This paper uncovers a non-cubic scaling law in disordered granular packings, linking it to jamming and contact number, challenging the universality of the scaling exponent.

Contribution

It demonstrates a non-cubic scaling law in granular materials and relates it to contact neighbors and jamming, providing new insights into packing behavior.

Findings

Non-cubic scaling law observed in granular packing

Scaling exponent around 2.5 linked to isostatic contact number

Exponent is not universal, varies with conditions

Abstract

Recent diffraction experiments on metallic glasses have unveiled an unexpected non-cubic scaling law between density and average interatomic distance, which lead to the speculations on the presence of fractal glass order. Using X-ray tomography we identify here a similar non-cubic scaling law in disordered granular packing of spherical particles. We find that the scaling law is directly related to the contact neighbors within first nearest neighbor shell, and therefore is closely connected to the phenomenon of jamming. The seemingly universal scaling exponent around 2.5 arises due to the isostatic condition with contact number around 6, and we argue that the exponent should not be universal.