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| Trung Vo, Thanh; Nezamabadi, Saeid; Mutabaruka, Patrick; Delenne, Jean-yves; Radjai, Farhang. |
| Granular flows are omnipresent in nature and industrial processes, but their rheological properties such as apparent friction and packing fraction are still elusive when inertial, cohesive and viscous interactions occur between particles in addition to frictional and elastic forces. Here we report on extensive particle dynamics simulations of such complex flows for a model granular system composed of perfectly rigid particles. We show that, when the apparent friction and packing fraction are normalized by their cohesion-dependent quasistatic values, they are governed by a single dimensionless number that, by virtue of stress additivity, accounts for all interactions. We also find that this dimensionless parameter, as a generalized inertial number,... |
| Tipo: Text |
Palavras-chave: Civil engineering; Colloids; Physics; Process chemistry; Rheology. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00685/79680/82460.pdf |
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| Vo, Thanh-trung; Mutabaruka, Patrick; Delenne, Jean-yves; Nezamabadi, Saeid; Radjai, Farhang. |
| We investigate the mechanical behavior of wet granular agglomerates composed of spherical particles by means of molecular dynamics simulations. The capillary cohesion force is modeled as an attraction force at the contact between two particles and expressed as an explicit function of the gap and volume of the liquid bridge. We are interested in the effect of the friction coefficient between primary particles. The agglomerates are subjected to diametrical compression tests. We find that the deformation is ductile involving particle rearrangements. However, a well-defined stress peak is observed and the peak stress is used as a measure of the compressive strength of the agglomerate. The strength increases with friction coefficient but levels off at friction... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00685/79694/82474.pdf |
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| Taiebat, Mahdi; Mutabaruka, Patrick; Pellenq, Roland; Radjai, Farhang. |
| We use molecular dynamics simulations of frictionless spherical particles to investigate a class of polydisperse granular materials in which the particle size distribution is uniform in particle volumes. The particles are assembled in a box by uniaxial compaction under the action of a constant stress. Due to the absence of friction and the nature of size distribution, the generated packings have the highest packing fraction at a given size span, defined as the ratio á of the largest size to the smallest size. We find that, up to á = 5, the packing fraction is a nearly linear function of á. While the coordination number is nearly constant due to the isostatic nature of the packings, we show that the connectivity of the particles evolves with á. In... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00685/79692/82472.pdf |
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| Vo, Thanh Trung; Nezamabadi, Saeid; Mutabaruka, Patrick; Delenne, Jean-yves; Izard, Edouard; Pellenq, Roland; Radjai, Farhang. |
| In order to get insight into the wet agglomeration process, we numerically investigate the growth of a single granule inside a dense flow of an initially homogeneous distribution of wet and dry particles. The simulations are performed by means of the discrete element method and the binding liquid is assumed to be transported by the wet particles, which interact via capillary and viscous force laws. The granule size is found to be an exponential function of time, reflecting the conservation of the amount of liquid and the decrease of the number of available wet particles inside the flow during agglomeration. We analyze this behavior in terms of the accretion and erosion rates of wet particles for a range of different values of material parameters such as... |
| Tipo: Text |
Palavras-chave: Flowing Matter; Granular Materials. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00685/79689/82470.pdf |
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| Mutabaruka, Patrick; Kumar, Krishna; Soga, Kenichi; Radjai, Farhang; Delenne, Jean-yves. |
| We investigate by means of Contact Dynamics simulations the transient dynamics of a 2D granular pile set into motion by applying shear velocity during a short time interval to all particles. The spreading dynamics is directly controlled by the input energy whereas in recent studies of column collapse the dynamics scales with the initial potential energy of the column. As in column collapse, we observe a power-law dependence of the runout distance with respect to the input energy with nontrivial exponents. This suggests that the power-law behavior is a generic feature of granular dynamics, and the values of the exponents reflect the distribution of kinetic energy inside the material. We observe two regimes with different values of the exponents: the... |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00685/79685/82468.pdf |
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| Amarsid, L.; Delenne, J.-y.; Mutabaruka, Patrick; Monerie, Y.; Perales, F.; Radjai, F.. |
| The shear behavior of granular materials immersed in a viscous fluid depends on fluid properties (viscosity, density), particle properties (size, density) and boundary conditions (shear rate, confining pressure). Using computational fluid dynamics simulations coupled with molecular dynamics for granular flow, and exploring a broad range of the values of parameters, we show that the parameter space can be reduced to a single parameter that controls the packing fraction and effective friction coefficient. This control parameter is a modified inertial number that incorporates viscous effects. |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00685/79693/82473.pdf |
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