3D numerical simulation study of quasistatic grinding process on a model granular material

Esnault, Vivien; Roux, Jean‐Noël

doi:10.1016/j.mechmat.2013.07.018

Cited by 23 publications

(20 citation statements)

References 58 publications

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“…Subsequently, Ben-Nun & Einav (2010) compared their breakage rule to that used previously by Tsoungui et al (1999) (based on a measure of average shear stress), and found that both breakage rules resulted in similar fractal PSDs. Esnault & Roux (2013) presented a DEM study which compared the use of a Von Mises criterion (using the average particle stresses) with the stress calculated from the largest contact force on a particle (F max /d 2 ). However, like many others, they allowed a 52% volume loss with each breakage, which, as they mentioned, neglects the mechanical role of smaller particles, something which is of greater interest herein.…”

Section: A Review Of Breakage Criteria Used In Demmentioning

confidence: 99%

Particle breakage criteria in discrete-element modelling

Bono

McDowell

2016

Géotechnique

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Previous work by the authors using the discrete-element method (DEM) has used the octahedral shear stress within a sphere together with a Weibull distribution of strengths and a size effect on average strength, to determine whether fracture occurs or not. This leads to fractal particle size distributions and a normal compression line which are consistent with experimental data. However, there is no agreement in the literature as to what the fracture criterion should be, and as yet it is not clear whether other criteria could lead to the correct evolution of voids ratio and particle size distribution under increasing stress. Various possibilities for the criterion have been studied in detail here to ascertain whether these other criteria may give the correct behaviour under normal compression. The use of the major principal stress within a particle, the mean stress and the stress calculated from the maximum contact force on a particle are each investigated as alternatives to the octahedral shear stress. Only the criterion based on the maximum contact force is shown to give behaviour observed experimentally and the simulations shed further insight into the micro mechanics of normal compression.

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Section: A Review Of Breakage Criteria Used In Demmentioning

confidence: 99%

Particle breakage criteria in discrete-element modelling

Bono

McDowell

2016

Géotechnique

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“…The drawback of the approach is that mass conservation is difficult to ensure and the results depend on the imposed breaking rules. The most realistic numerical studies of fault gouge formation were performed in the framework of discrete element models where macroscopic particles were assembled of spheres or polyhedra glued together with breakable cohesive contacts [14][15][16]. Computer simulation of shear cells resulted in power law size distributions of fragments with exponents close to the experimental values.…”

Section: Introductionmentioning

confidence: 99%

Fragmentation and shear band formation by slow compression of brittle porous media

et al. 2016

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Localized fragmentation is an important phenomenon associated with the formation of shear bands and faults in granular media. It can be studied by empirical observation, by laboratory experiment, or by numerical simulation. Here we investigate the spatial structure and statistics of fragmentation using discrete element simulations of the strain-controlled uniaxial compression of cylindrical samples of different finite size. As the system approaches failure, damage localizes in a narrow shear band or synthetic fault "gouge" containing a large number of poorly sorted noncohesive fragments on a broad bandwidth of scales, with properties similar to those of natural and experimental faults. We determine the position and orientation of the central fault plane, the width of the shear band, and the spatial and mass distribution of fragments. The relative width of the shear band decreases as a power law of the system size, and the probability distribution of the angle of the central fault plane converges to around 30 degrees, representing an internal coefficient of friction of 0.7 or so. The mass of fragments is power law distributed, with an exponent that does not depend on scale, and is near that inferred for experimental and natural fault gouges. The fragments are in general angular, with a clear self-affine geometry. The consistency of this model with experimental and field results confirms the critical roles of preexisting heterogeneity, elastic interactions, and finite system size to grain size ratio on the development of shear bands and faults in porous media.

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“…This bonded particle model (BPM) has been employed to investigate the behavior of crushable soils, rocks, fault gouge, and other materials [7,22,[32][33][34][35][36][37][38][39][40][41]. An alternative method consists in replacing a circular or spherical particle at its fracture threshold by several smaller fragments of the same shape [42][43][44][45][46]. A major issue with these methods is that an aggregate of spherical subparticles includes voids, so its breakup leads to considerable loss of volume.…”

Section: Introductionmentioning

confidence: 99%

Bonded-cell model for particle fracture

et al. 2015

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Particle degradation and fracture play an important role in natural granular flows and in many applications of granular materials. We analyze the fracture properties of two-dimensional disklike particles modeled as aggregates of rigid cells bonded along their sides by a cohesive Mohr-Coulomb law and simulated by the contact dynamics method. We show that the compressive strength scales with tensile strength between cells but depends also on the friction coefficient and a parameter describing cell shape distribution. The statistical scatter of compressive strength is well described by the Weibull distribution function with a shape parameter varying from 6 to 10 depending on cell shape distribution. We show that this distribution may be understood in terms of percolating critical intercellular contacts. We propose a random-walk model of critical contacts that leads to particle size dependence of the compressive strength in good agreement with our simulation data.

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3D numerical simulation study of quasistatic grinding process on a model granular material

Cited by 23 publications

References 58 publications

Particle breakage criteria in discrete-element modelling

Particle breakage criteria in discrete-element modelling

Fragmentation and shear band formation by slow compression of brittle porous media

Bonded-cell model for particle fracture

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