Dresden 2017 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 56: Posters - Granular and Particulate Matter

DY 56.5: Poster

Thursday, March 23, 2017, 17:00–19:30, P1A

Densest Local Structures and Packing Properties of Uniaxial Ellipsoids — •Robert F. B. Weigel, Fabian M. Schaller, and Sebastian C. Kapfer — Institut für Theoretische Physik, FAU Erlangen-Nürnberg, 91058 Erlangen, Germany

The relationship between local structure and macroscopic properties is a current research focus in granular matter. We study the distribution of local packing fractions (defined via Voronoi cell volumina) which is a sensitive observable for characterizing these systems. Previously, mainly packings of spherical particles were considered. Here, we focus on packings of uniaxial ellipsoids as an instance of aspherical particles [1]. In particular, we generalize the famous “kissing problem” and report numerical results on the densest local structures of ellipsoids with aspect ratio between 0.7 (oblate) and 1.4 (prolate). Like in the spherical case, these packings locally exceed the density of known ellipsoid crystals. Analogous to results for lattice packings [2], we find that ellipsoids pack denser than spheres, and with more neighbors. In dense disordered packings of ellipsoids, distorted variations of some of our densest packing motifs can be identified. Our results permit us to generalize and test the k-Gamma model for local packing fraction distributions, previously only applicable to spherical particles [3].
Fabian Schaller et al., Phys. Rev. X 6, 041032 (2016)
Yoav Kallus, Adv. Math. 264, 355–370 (2014)
Tomaso Aste et al., Europhys. Lett. 79, 24003 (2007)