Structural Characterization and Statistical Properties of Two-Dimensional Granular Systems During the Compaction |

S. Živković
^{a}, Z.M. Jakšić^{a}, D. Arsenović^{a}, Lj. Budinski-Petković^{b}, S.B. Vrhovac^{a}^{a}Institute of Physics, University of Belgrade, P.O. Box 68, Zemun 11080, Belgrade, Serbia
^{b}Faculty of Engineering, Trg. D. Obradovića 6, Novi Sad 21000, Serbia |

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We study the compaction dynamics of frictional hard disks in two dimensions, subjected to vertical shaking, by numerical simulation. Shaking is modeled by a series of vertical expansions of the disk packing, followed by dynamical recompression of the assembly under the action of gravity. The second phase of the shake cycle is based on an efficient event-driven molecular-dynamics algorithm. We analyze the compaction dynamics for various values of the friction coefficient and the coefficient of normal restitution. The granular organization at local level was studied by analyzing the shape factor ξ of the local volumes, associated with a natural way of subdividing the volume into local parts - the Voronoi partition. It gives a clear physical picture of the competition between less and more ordered domains of particles during the compaction. We calculate the distribution of the shape-factor for packings at different stages of the compaction process. We have also investigated a two-dimensional granular medium experimentally. We prepared the granular packings of metallic cylinders of diameters 4, 5, and 6 mm. The distributions of the shape-factor obtained numerically for various tapping intensities are consistent with our experimental results. |

DOI: 10.12693/APhysPolA.120.246 PACS numbers: 45.70.-n, 45.70.Cc, 81.05.Rm, 61.43.Bn |