Arching effect analysis of granular media based on force chain visualization

Fang, Yingguang; Guo, Lingfeng; Hou, Mingxun

doi:10.1016/j.powtec.2020.01.038

Cited by 34 publications

(5 citation statements)

References 26 publications

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“…Such arches act as a "stress shield," maintaining the low contact forces within their interior. This effect was recently studied by Fang et al (32). Within the low stress zone, cohesive forces comparable with the weight of one grain are strong enough to support unloaded grains, allowing stable tunnels underneath pounds of earth.…”

Section: Resultsmentioning

confidence: 92%

“…Nonetheless, we are more interested in capturing the general behavior of forces in our sample-such as the dependence of force chain morphology on the growth of the tunnel. This emergent behavior is more dependent on the distribution of particle shapes and boundary conditions than on the specific contact locations (22,32). In this regard, LS-DEM has shown high efficacy (33).…”

Section: Resultsmentioning

confidence: 99%

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Unearthing real-time 3D ant tunneling mechanics

Macedo

Andò

Joy

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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Granular excavation is the removal of solid, discrete particles from a structure composed of these objects. Efficiently predicting the stability of an excavation during particle removal is an unsolved and highly nonlinear problem, as the movement of each grain is coupled to its neighbors. Despite this, insects such as ants have evolved to be astonishingly proficient excavators, successfully removing grains such that their tunnels are stable. Currently, it is unclear how ants use their limited information about the environment to construct lasting tunnels. We attempt to unearth the ants’ tunneling algorithm by taking three-dimensional (3D) X-ray computed tomographic imaging (XRCT), in real time, of Pogonomyrmex ant tunnel construction. By capturing the location and shape of each grain in the domain, we characterize the relationship between particle properties and ant decision-making within an accurate, virtual recreation of the experiment. We discover that intergranular forces decrease significantly around ant tunnels due to arches forming within the soil. Due to this force relaxation, any grain the ants pick from the tunnel surface will likely be under low stress. Thus, ants avoid removing grains compressed under high forces without needing to be aware of the force network in the surrounding material. Even more, such arches shield tunnels from high forces, providing tunnel robustness. Finally, we observe that ants tend to dig piecewise linearly downward. These results are a step toward understanding granular tunnel stability in heterogeneous 3D systems. We expect that such findings may be leveraged for robotic excavation.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Unearthing real-time 3D ant tunneling mechanics

Macedo

Andò

Joy

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Local stress arch units and the macroscopic arch structure will change the stress transmission path in the pile and cause the stress to transmit along with the mutually wedged contact points of ring-shaped arches, which will produce the jamming [19] phenomenon that the stress transfers by bypassing the particles inside the arches; i.e., a blocking phenomenon of the stress transmission causing by the arching effect. The blocking phenomenon of stress transmission will then produce a "stress shielding effect" [39], which can significantly increase the stress outside the arch and decrease the stress inside the arch, and form the non-uniform stress distribution phenomenon. The inter-particle contact force cloud map shown in Fig.…”

Section: The Stress Shielding Effect Of the Stress Archmentioning

confidence: 99%

The experiment and analysis of the repose angle and the stress arch-caused stress dip of the sandpile

Fang

Guo

et al. 2021

Granular Matter

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The repose angle and characteristics of the vertical stress distribution beneath the sandpile can help to understand the physical and mechanical properties of the granular matter and guide the foundation design of the rock-soil deposits such as the rockfill dam and the storage structures of granular materials. Researches previously found that the stress dip phenomenon exists in piles constructed by the localized-source procedure, where the maximum vertical stress underneath the pile deviates from the center. The repose angle and the stress dip are affected by many internal and external factors and exhibit highly nonlinear and sensitive characteristics. However, the variation of the repose angle and the stress dip with influencing factors and the cause of the stress dip have not yet been fully explored. Based on the localized-source conical sandpile experiments and the discrete element method (DEM) simulation analysis, this paper studied the influences of the internal friction angle of granular matter and the construction history (the slowly raising funnel method SRFM and the fixed funnel method FFM) on the repose angle and the vertical stress dip beneath the pile; while the formation mechanism of the stress dip phenomenon was analyzed. The experimental results showed that the repose angle, physically different from the internal friction angle, has a relatively larger value and is positively related to the internal friction angle in the sandpile constructed by the FFM; the localized-source procedure and the internal friction angle are conducive to the formation of the macroscopic force chain arch structure in granular matter, which produces the arching effect and the stress shielding effect and leads to the stress dip beneath the pile; and the ratio of the stress dip RSD decreases with the increase of the local impact effect and the internal friction angle.

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“…Rui et al [17] conducted a DEM simulation analysis of the trapdoor tests by considering different soil heights and trapdoor widths, and observed three patterns in the evolution of soil arches namely the triangular expansion pattern, evolution and equal settlement patterns. In addition, the digital image correlation technique and the visualization of force chains are used to probe the mechanism of the soil arching [18] [19].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the fabric effect on the arching effect in granular materials

Deng,

Dai

2024

IOP Conf. Ser.: Earth Environ. Sci.

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A series of trapdoor experiments and DEM simulations were carried out in this study to examine the arching effect in granular materials, with the focus being on the influence of the direction for particle deposition. In the tests, particles (e.g. rice grains, PVC particles and nylon particles) were dropped as if they were raining at different directions to construct granular material layers with various fabric orientations. It is shown that the mobilization of arching effect depends on the direction of particle deposition, with the arching ratio ρ increasing at first and then decreasing. The arching effect is the weakest at a deposition angle of θ = 30° in obliquely deposited granular masses. It is also found that the vertical displacement of particles in the ultimate phase increases initially; it then decreases with the variation in the orientation of particle deposition, and the largest displacement occurs at θ = 30°.

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Arching effect analysis of granular media based on force chain visualization

Cited by 34 publications

References 26 publications

Unearthing real-time 3D ant tunneling mechanics

Unearthing real-time 3D ant tunneling mechanics

The experiment and analysis of the repose angle and the stress arch-caused stress dip of the sandpile

Investigation of the fabric effect on the arching effect in granular materials

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