Lionel Pournin

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We first describe the three-dimensional extension of the molecular-dynamics models for granular media simulations. We then discuss the known energy dissipation problem occurring when simulating dense granular media with the usual molecular-dynamics forces models. We finally propose a force model able to control the energy dissipation in the multiparticle(More)
We study the jamming of bead assemblies placed in a cylindrical container whose bottom is pierced with a circular hole. Their jamming behavior is quantified here by the median jamming diameter, that is the diameter of the hole for which the jamming probability is 0.5. Median jamming diameters of monodisperse assemblies are obtained numerically using the(More)
A polyhedral subdivision of a d-dimensional point configuration A is k-regular if it is projected from the boundary complex of a polytope with dimension at most d+k. Call γk(A) the subgraph induced by k-regular triangulations in the flip-graph of A. Gel’fand, Kapranov, and Zelevinsky have shown that γ1(A) is connected. It is established here that γ2(A) is(More)
Granular media composed of elongated particles rearrange and order vertically upon vertical vibration. We perform pseudo-two-dimensional discrete element model simulations and show that this phenomenon also takes place with no help from vertical walls. We quantitatively analyze the sizes of voids forming during vibrations and consider a void-filling(More)
Concealing their rich structure behind apparent simplicity, Voronoi diagrams and their dual Siamese twins, the Delaunay triangulations constitute remarkably powerful and ubiquitous concepts well beyond the realm of mathematics. This may be why they have been discovered and rediscovered time and again. They were already present in fields as diverse as(More)
We describe particular paths in the flip-graph of regular triangulations in any dimension. It is shown that any pair of regular triangulations is connected by a path along which none of their common faces are destroyed. As a consequence, we obtain the connectivity of the flip-graph of regular triangulations that share the same vertex set. © 2006 Elsevier(More)