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Published on: September 26, 2014
Disordered strictly jammed binary sphere packings attain an anomalously large range of densities
Adam B Hopkins1, Frank H Stillinger, Salvatore Torquato
1Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 17, 2013
Summary
Researchers created stable, disordered binary sphere packings with a wide range of densities. These high-density packings could be useful for materials science and may form glasses, advancing granular composite and glass-forming research.
Area of Science:
- Physics
- Materials Science
- Computational Science
Background:
- Simulating disordered sphere packings is challenging, especially for achieving mechanically stable and isostatic configurations across various densities.
- Previous methods struggled to produce stable packings with a broad range of packing fractions.
Purpose of the Study:
- To develop a method for creating mechanically stable, isostatic, and disordered binary sphere packings with an extended range of packing fractions.
- To investigate the properties of these packings, including their backbone structure and packing fraction.
Main Methods:
- Utilized an implementation of the Torquato-Jiao sequential linear programming algorithm to generate inherent structures.
- Focused on disordered strictly jammed binary packings, ensuring mechanical stability under deformation.
- Analyzed packings across a range of sphere radius ratios (α) and number concentrations (x).
Main Results:
- Achieved an anomalously large range of average packing fractions (0.634–0.829) for disordered strictly jammed binary packings.
- Identified that a subset of spheres (the backbone) is strictly jammed and isostatic.
- Observed backbone packing fractions to be consistently around 0.624, with variations in rattler sphere volume (1.6%–26.9%).
Conclusions:
- The findings suggest that these high-density disordered packings are promising candidates for glass formers due to entropic reasons.
- The developed method offers a way to experimentally prepare such packings, with implications for granular composites like propellants, concrete, and ceramics.
- The study provides insights into the structure and density of jammed binary packings relevant to multicomponent metallic glass formation.
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