Mapping the jamming transition of bidisperse mixtures

TL;DR

This study systematically maps the jamming transition in 2D bidisperse frictionless disk mixtures, revealing how critical parameters vary with composition and particle size ratio, and identifying regions with distinct structural and mechanical properties.

Contribution

It provides a comprehensive analysis of how mixture composition influences jamming properties, highlighting two minima in critical volume fraction and regions with unique structural order and stiffness.

Findings

Two local minima in critical volume fraction near specific mixtures

Structural order and rattler fractions vary significantly with size ratio

Enhanced stiffness observed in low size ratio regions

Abstract

We systematically map out the jamming transition of all 2D bidisperse mixtures of frictionless disks in the hard particle limit. The critical volume fraction, mean coordination number, number of rattlers, structural order parameters, and bulk modulus each show a rich variation with mixture composition and particle size ratio, and can therefore be tuned by choosing certain mixtures. We identify two local minima in the critical volume fraction, both of which have low structural order; one minimum is close to the widely studied 50:50 mixture of particles with a ratio of radii of 1:1.4. We also identify a region at low size ratios characterized by increased structural order and high rattler fractions, with a corresponding enhancement in the stiffness.