206 citations · 5k across the 136 of their papers we have counts for
19 papers · 1 filter
Ratcheting of granular materials
F. Alonso-Marroquin, H. J. Herrmann
We investigate the quasi-static mechanical response of soils under cyclic loading using a discrete model of randomly generated convex polygons. This response exhibits a sequence of…
Modelling transverse dunes
Veit Schwämmle, Hans J. Herrmann
Transverse dunes appear in regions of mainly unidirectional wind and high sand availability. A dune model is extended to two dimensional calculation of the shear stress. It is appl…
Analysis of the elasto-plastic response of a polygonal packing
F. Alonso-Marroquin, H. J. Herrmann, S. Luding
We investigate the constitutive response of two-dimensional packed samples of polygons using molecular dynamics simulation. The incremental elasto-plastic response is examined in t…
Models for Free Granular Surfaces
R. Mulet, H. Herrmann
We introduce two sets of continuum equations to describe granular flow on a free surface and study their properties. The equations derived from a microscopic picture that includes…
A ``Tetris''-like model for the Compaction of Dry Granular Media
E. Caglioti, V. Loreto, H. J. Herrmann +1
We propose a two-dimensional geometrical model, based on the concept of geometrical frustration, conceived for the study of compaction in granular media. The dynamics exhibits an i…
Fragmentation of Colliding Discs
F. Kun, H. J. Herrmann
We study the phenomena associated with the low-velocity impact of two solid discs of equal size using a cell model of brittle solids. The fragment ejection exhibits a jet-like stru…
A model for the compaction of granular media
Mario Nicodemi, Antonio Coniglio, Hans J. Herrmann
We introduce a lattice model, in which frustration plays a crucial role, to describe relaxation properties of granular media. We show Monte Carlo results for compaction in the pres…
Density waves in dry granular media falling through a vertical pipe
T. Raafat, J. P. Hulin, H. J. Herrmann
We report experimental measurements of density waves in granular materials flowing down in a capillary tube. The density wave regime occurs at intermediate flow rates between a low…
On the Shape of the Tail of a Two Dimensional Sand Pile
J. J. Alonso, H. J. Herrmann
We study the shape of the tail of a heap of granular material. A simple theoretical argument shows that the tail adds a logarithmic correction to the slope given by the angle of re…
A reaction-diffusion model for the hydration/setting of cement
F. Tzschichholz, H. J. Herrmann, H. Zanni
We propose a heterogeneous reaction-diffusion model for the hydration and setting of cement. The model is based on diffusional ion transport and on cement specific chemical dissolu…
On Hydrodynamic Diffusion and Velocity Fluctuations in Two--Dimensional Simulations of Sedimentation
W. Kalthoff, S. Schwarzer, G. H. Ristow +1
We present a numerical method to deal efficiently with large numbers of particles in incompressible fluids. The interactions between particles and fluid are taken into account by a…
Density waves of granular flow in a pipe using lattice gas automata
Gongwen Peng, Hans J Herrmann
Density waves of granular flow in a pipe using lattice gas automata Gongwen Peng and Hans J. Herrmann HLRZ, KFA Jülich, D--52425 Jülich, Germany We use a lattice gas automaton mode…
Deterministic Models for Traffic Jams
Kai Nagel, Hans J. Herrmann
We study several deterministic one-dimensional traffic models. For integer positions and velocities we find the typical high and low density phases separated by a simple transition…
Lattice Boltzmann Models for Complex Fluids
E. G. Flekkoy, H. J. Herrmann
We present various Lattice Boltzmann Models which reproduce the effects of rough walls, shear thinning and granular flow. We examine the boundary layers generated by the roughness…
A Simple Geometrical Model for Solid Friction
T. Poeschel, H. J. Herrmann
We present a simple model for the friction of two solid bodies moving against each other. In a self consistent way we can obtain the dependence of the macroscopic friction force as…
Density Patterns in Granular Media
G. Ristow, H. J. Herrmann
Recent experiments by Baxter et al. showed the existence of density waves in granular material flowing out of a hopper. We show, using Molecular Dynamics Simulations, that this eff…
Diffusion and spectral dimension on Eden tree
Hisao Nakanishi, Hans J. Herrmann
We calculate the eigenspectrum of random walks on the Eden tree in two and three dimensions. From this, we calculate the spectral dimension and the walk dimension and t…
Angle of Repose and Angle of Marginal Stability: Molecular Dyanmics of Granular Particles
Jysoo Lee, Hans J. Herrmann
We present an implementation of realistic static friction in molecular dynamics (MD) simulations of granular particles. In our model, to break contacts between two particles, one h…
On the Thermodynamics of Granular Media
H. J. Herrmann
A thermodynamic formulation for moving granular material is proposed. The fluctuations due to the constant flux and dissipation of energy are controlled in a `granular' ensemble by…