Local stresses in the Janssen granular column

Hure, Jérémy; Marthelot, Joël

doi:10.1103/physreve.88.022204

Cited by 17 publications

(15 citation statements)

References 29 publications

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“…shows that L c depends also on the grain size d which is not a parameter of the model so far because the granular mater is assumed to be continuous in the derivation of the shear stress, Eq. (2), in agreement with experiments for d/2R 0.1 [43,44]. Therefore, neither the grain size nor the rigidity of the cylinder affect the stress distribution in the regimes considered here [43,44].…”

Section: Figure 3(d)supporting

confidence: 88%

“…0.1 [43,44]. Therefore, neither the grain size nor the rigidity of the cylinder affect the stress distribution in the regimes considered here [43,44].…”

mentioning

confidence: 84%

“…0.1 [43,44]. Therefore, neither the grain size nor the rigidity of the cylinder affect the stress distribution in the regimes considered here [43,44]. One must then search for another explanation for the dependence of L c on d. In the regime d t we consider, the silo wall is slightly deformed once it is filled with the grains.…”

mentioning

confidence: 91%

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Silo Collapse under Granular Discharge

et al. 2015

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We investigate, at a laboratory scale, the collapse of cylindrical shells of radius R and thickness t induced by a granular discharge. We measure the critical filling height for which the structure fails upon discharge. We observe that the silos sustain filling heights significantly above an estimation obtained by coupling standard shell-buckling and granular stress distribution theories. Two effects contribute to stabilize the structure: (i) below the critical filling height, a dynamical stabilization due to granular wall friction prevents the localized shell-buckling modes to grow irreversibly; (ii) above the critical filling height, collapse occurs before the downward sliding motion of the whole granular column sets in, such that only a partial friction mobilization is at play. However, we notice also that the critical filling height is reduced as the grain size d increases. The importance of grain size contribution is controlled by the ratio d= ffiffiffiffiffi Rt p . We rationalize these antagonist effects with a novel fluid-structure theory both accounting for the actual status of granular friction at the wall and the inherent shell imperfections mediated by the grains. This theory yields new scaling predictions which are compared with the experimental results.

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Section: Figure 3(d)supporting

confidence: 88%

“…0.1 [43,44]. Therefore, neither the grain size nor the rigidity of the cylinder affect the stress distribution in the regimes considered here [43,44].…”

mentioning

confidence: 84%

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Silo Collapse under Granular Discharge

et al. 2015

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“…In order to solve it, constant b was assumed to be equal to 1. Constant B * 1 was computed using the characteristic values of our experiments, i.e., D = 3 mm, d = d 50 = 0.225 mm (the latter value obtained by SEM), and we assumed that µ s = tan(32 o ), κ ≈ 0.5, and c 0 ≈ 0.55 [1,24]. Additionally, we assumed θ ≤ 5 o .…”

Section: Stability Analysismentioning

confidence: 99%

Intermittent gravity-driven flow of grains through narrow pipes

Alvarez

Franklin

2017

Physica A: Statistical Mechanics and its Applications

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Grain flows through pipes are frequently found in various settings, such as in pharmaceutical, chemical, petroleum, mining and food industries. In the case of size-constrained gravitational flows, density waves consisting of alternating high-and low-compactness regions may appear. This study investigates experimentally the dynamics of density waves that appear in gravitational flows of fine grains through vertical and slightly inclined pipes. The experimental device consisted of a transparent glass pipe through which different populations of glass spheres flowed driven by gravity. Our experiments were performed under controlled ambient temperature and relative humidity, and the granular flow was filmed with a high-speed camera. Experimental results concerning the length scales and celerities of density waves are presented, together with a one-dimensional model and a linear stability analysis. The analysis exhibits the presence of a long-wavelength instability, with the most unstable mode and a cut-off wavenumber whose values are in agreement with the experimental results.

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“…Although the packing column confined in a container can also act as a simple but valid experimental system to test many theoretical models for the repartition or the transmission of stresses in granular materials [22][23][24][25], the mechanical behavior of the packing of granular chains did not receive enough attention until Brown et al revealed that a stress response in granular chains was very distinct from common grains, namely individual grains [26]. They found that strain stiffening occurred in the packing of long chains due to the inter-chains entanglements, which are absent in the packing system of individual grains or short chains.…”

Section: Introductionmentioning

confidence: 99%

Bottom stresses of static packing of granular chains

Wen¹,

Wang²,

Hao³

et al. 2015

Physica A: Statistical Mechanics and its Applications

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h i g h l i g h t s• Bottom stress of a granular chains column is measured precisely and reproducibly.• Scaling behavior of the stress saturation curves agrees with the Janssen model. • Saturation mass is shown as a nonmonotonic function of the chain length.• A transition of the saturation mass is found at the persistence length of chains. • Entanglements as a possible explanation for nonmonotonic behavior are presented. a b s t r a c tWe experimentally measure the static stress at the bottom of a granular chains column with a precise and reproducible method. The relation, between the filling mass and the apparent mass converted from the bottom stress, is investigated on various chain lengths. Our measurements reconfirm that the scaling behavior of the stress saturation curves is in accord with the theoretical expectation of the Janssen model. Additionally, the saturation mass is displayed as a nonmonotonic function of the chain length, where a distinguishing transition of the saturation mass is found at the persistence length of the granular chain. We repeat the measurement with another measuring methodology and a silo with different size, respectively, the position of the peak maintains robust. In order to understand the transition of the saturation mass, the friction coefficient and the volume fraction of granular chains are also measured, from which Janssen parameter can be calculated. Finally, we preliminarily measure the bottom stress for two distinct packing structures of long chains, find the effect of the entanglements on the bottom stress, and argue that the entanglements might be responsible for the transition of the saturation mass.

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Local stresses in the Janssen granular column

Cited by 17 publications

References 29 publications

Silo Collapse under Granular Discharge

Silo Collapse under Granular Discharge

Intermittent gravity-driven flow of grains through narrow pipes

Bottom stresses of static packing of granular chains

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