Universal scaling laws for shear induced dilation in frictional granular media

Bandi, Mahesh; Das, Prasenjit; Gendelman, Oleg; Hentschel, H. G. E.; Procaccia, Itamar

doi:10.1007/s10035-019-0890-x

Cited by 8 publications

(6 citation statements)

References 27 publications

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“…A traditional subject of research are stress-fluctuations [53][54][55][56], and the quest for the "effective temperature" [47,48,57,58] of thermal or a-thermal granular packings [48,52,59]. Most recently, universal scaling laws [60] were reported, and compression and shear in particularly small systems [61] could be understood. Considering granular solids, their stiffness, and the elastic moduli [31,62,63] have to be considered in the presence of non-affine deformations [63].…”

Section: A Brief History Of Granular Researchmentioning

confidence: 99%

“…Considering granular solids, their stiffness, and the elastic moduli [31,62,63] have to be considered in the presence of non-affine deformations [63]. For this, overcompression [45,49] and shear [49,60,62,[64][65][66] cyclic loading [66,67] or even thermal cyclic loading [68] were applied. When sheared granular matter starts to flow and (for large enough strain) reaches a steady state, or critical state [69][70][71], the nowadays widely accepted "classical" (I) -rheology [72] holds.…”

Section: A Brief History Of Granular Researchmentioning

confidence: 99%

“…It was recently extended to include friction, softness and cohesion [2,12,13,69,70,[73][74][75], but it does not have a fully tensorial form [76,77], and doubts about its well-posed-ness are still discussed [78][79][80]. Modern experimental techniques [25,71,81,82], also with focus on low confining stress [83], shed new light on classical works on the response to local perturbations [84], jamming and un-jamming [23,[84][85][86][87], in particular by shear [10,49,60,65,[88][89][90], and transient fabric/micro-structure evolution [31,49,55,[91][92][93][94]. One of the classical experimental techniques involves photoelastic materials that allow to visualize stress [95][96][97], as complemented by a huge amount of particle simulations, e.g., see Ref.…”

Section: A Brief History Of Granular Researchmentioning

confidence: 99%

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Un-jamming due to energetic instability: statics to dynamics

2021

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Jamming/un-jamming, the transition between solid- and fluid-like behavior in granular matter, is an ubiquitous phenomenon in need of a sound understanding. As argued here, in addition to the usual un-jamming by vanishing pressure due to a decrease of density, there is also yield (plastic rearrangements and un-jamming that occur) if, e.g., for given pressure, the shear stress becomes too large. Similar to the van der Waals transition between vapor and water, or the critical current in superconductors, we believe that one mechanism causing yield is by the loss of the energy’s convexity (causing irreversible re-arrangements of the micro-structure, either locally or globally). We focus on this mechanism in the context of granular solid hydrodynamics (GSH), generalized for very soft materials, i.e., large elastic deformations, employing it in an over-simplified (bottom-up) fashion by setting as many parameters as possible to constant. Also, we complemented/completed GSH by using various insights/observations from particle simulations and calibrating some of the theoretical parameters—both continuum and particle points of view are reviewed in the context of the research developments during the last few years. Any other energy-based elastic-plastic theory that is properly calibrated (top-down), by experimental or numerical data, would describe granular solids. But only if it would cover granular gas, fluid, and solid states simultaneously (as GSH does) could it follow the system transitions and evolution through all states into un-jammed, possibly dynamic/collisional states—and back to elastically stable ones. We show how the un-jamming dynamics starts off, unfolds, develops, and ends. We follow the system through various deformation modes: transitions, yielding, un-jamming and jamming, both analytically and numerically and bring together the material point continuum model with particle simulations, quantitatively. Graphic abstract

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Section: A Brief History Of Granular Researchmentioning

confidence: 99%

Section: A Brief History Of Granular Researchmentioning

confidence: 99%

Section: A Brief History Of Granular Researchmentioning

confidence: 99%

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Un-jamming due to energetic instability: statics to dynamics

2021

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“…In the inertial regime, when a dense granular system is subjected to continuous shear, a local flow near the boundary is first generated after the initial static equilibrium is broken, and gradually a global flow will be achieved and maintained stable finally. Meanwhile, the shear flow is accompanied with dilatancy, which represents the volume expansion of the granular system [15][16][17][18]. Two representative quantities, i.e., the interfacial friction coefficient and the shear strength, are most commonly employed to characterize the rheological properties of dense granular flow [19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Transient Evolution of Rheological Properties of Dense Granular Inertial Flow Under Plane Shear

et al. 2022

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Exploration on the transient evolution of the rheological properties of dense granular inertial flow is essential for revealing how the balance is established between the boundary drive strength and the internal shear strength. In this paper, discrete element method simulations are performed to study the transient flow characteristics of a dense granular system under plane shear in the inertial regime. To this end, we quantitatively analyze the changes in the system's flow state, interfacial friction coefficient, internal friction coefficient, and microstructure. Simulation results show that the evolution of the horizontal flow experiences three typical stages, namely transmission, adjustment, and stabilization. Meanwhile, the shear dilatancy caused by the vertical movement of particles, gradually loosens the filling state, weakens the spatial geometric constraint and the system's tangential load-bearing capacity, thereby decreasing the interfacial friction coefficient and reducing the boundary drive strength.On the other hand, the variations in the anisotropies of both contact orientation and contact forces, increase the internal friction coefficient and improve the internal shear strength. Therefore, the evolution of flow state from initially static to finally stable reduces the boundary drive strength while enhances the internal shear strength, and eventually a balance between them is achieved. Distinguished from the micromechanical behaviors, under different shear velocities the internal shear strength always mainly originates from the anisotropies in contact orientation and in normal contact force. Moreover, the contribution of the anisotropy in contact orientation becomes more predominant with the increase of shear velocity.

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“…Much less is known about the evolution of shear zones in more realistic media (as, for example, in geological processes) where the system is confined or subjected to an external pressure. Under such conditions, the dilation behavior and microstructure of granular materials change [21][22][23][24][25][26][27] which is expected to influence the flow profile. It was predicted based on an energy-dissipation variational approach that applying an external pressure should result in a similar behavior as observed with increasing filling height [17].…”

Section: Introductionmentioning

confidence: 99%