A three-dimensional discrete element model using arrays of ellipsoids

Lin, Xiongbin; Ng, T. T.

doi:10.1680/geot.1997.47.2.319

Cited by 323 publications

(143 citation statements)

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“…The DEM code used in this study was a modified version of ELLIPSE3D [6] which is based upon the TRUBAL code developed by Cundall and Strack [7]. This code was modified in the current study, following previous updates by O'Sullivan [8] and Cui [9].…”

Section: Simulation Parameters and Specimen Generationmentioning

confidence: 99%

“…When Thornton [2] analysed the results of constant b-value tests he proposed that a peak fabric envelope could be represented using an "inverted" Lade & Duncan envelope described by: [6] where  1 ,  2 and  3 , are the principal values of the fabric tensor. The peak fabric envelopes for the simulations in the current study are also included in Figure 12.…”

Section: Simulation Parameters and Specimen Generationmentioning

confidence: 99%

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The influence of inter-particle friction and the intermediate stress ratio on soil response under generalised stress conditions

2012

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Previous research studies have used either physical experiments or discrete element method (DEM) simulations to explore, independently, the influence of the coefficient of inter-particle friction () and the intermediate stress ratio (b) on the behaviour of granular materials. DEM simulations and experiments using photoelasticity have shown that when an anisotropic stress condition is applied to a granular material, strong force chains or columns of contacting particles transmitting relatively large forces, form parallel to the major principal stress orientation. The combined effects of friction and the intermediate stress ratio upon the resistance of these strong force chains to collapse (buckling failure) are considered here using data from an extensive set of DEM simulations including triaxial and true triaxial compression tests. For all tests both  and b affected the macroand micro-scale response, however the mechanisms whereby the force chain stability was improved differ. While friction clearly enhances the inherent stability of the strong force chains, the intermediate stress ratio affects the contact density and distribution of orthogonal contacts that provide lateral support to the force chains.

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Section: Simulation Parameters and Specimen Generationmentioning

confidence: 99%

Section: Simulation Parameters and Specimen Generationmentioning

confidence: 99%

The influence of inter-particle friction and the intermediate stress ratio on soil response under generalised stress conditions

2012

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“…The DEM simulations described in this paper used a DEM code called 3DDEM, developed by O'Sullivan (2002) and Cui (2006) based on the ELLIPSE3D code (Lin & Ng, 1997). In the simulations the top and bottom boundaries were modelled using planar rigid wall boundaries.…”

Section: Implementation Of the Mixed Boundary Test Environmentmentioning

confidence: 99%

An analysis of the triaxial apparatus using a mixed boundary three-dimensional discrete element model

2007

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The triaxial test is probably the most important fundamental laboratory test for geotechnical engineers. The objective of the study presented here was to gain insight into the micro-scale interactions experienced by particles during a triaxial test using the distinct element method (DEM). To achieve this objective, a novel DEM modelling environment to simulate triaxial tests on ideal granular materials was implemented, as described here. In this test environment, both the stress conditions and boundary conditions in the physical tests can be accurately reproduced. This approach was quantitatively validated by simulating a number of physical triaxial tests on specimens of steel spheres. A comparison between the circumferential periodic boundaries used here and the circumferential rigid boundaries used by other researchers emphasises the significance of maintaining a continuous particle-particle contact network orthogonal to the major principal stress direction.Results of an analysis of the micro-scale response in a triaxial simulation are analysed in detail, including the stresses, the distribution of contact forces, the evolution of fabric, the distribution of local strains, and the particle rotations. Significant non-uniformities in the stresses, strains and contact fabric were observed.

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“…While more complex geometries, such as ellipsoids (e.g. Lin andNg (1997), Ng (2004)) can be used, their use increases the computational cost of the simulations as a non-linear equation needs to be solved at each contact point at each time increment to determine the inter-particle forces.…”

Section: Figure 1 Modeling Contact In Discrete Element Simulationsmentioning

confidence: 99%

“…This code is a modified version of Ellipse3D (Lin and Ng, 1997), which in turn is a modified version of Trubal (Cundall and Strack, 1979). The initial stage of the analysis was to calibrate the numerical model.…”

Section: Overview Of Tests and Modeling Approachmentioning

confidence: 99%

Experimental Validation of Particle-Based Discrete Element Methods

2006

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As a consequence of its particulate nature, soil exhibits a highly complex response to applied loads and deformations. Traditionally, geotechnical engineers have coupled continuum numerical analysis tools (such as the finite element method) with complex constitutive models to analyze soil response. This approach does not explicitly consider the particle-scale interactions underlying the macro-scale response observed in the laboratory and field. With increasing computational speeds, particle-based discrete element methods are becoming popular amongst geotechnical engineers in both research and practice. On a practical level discrete element methods are particularly useful for studying finite deformation problems, while from a more theoretical perspective they can be used to create virtual laboratories where the micro-mechanics of soil response can be analyzed in detail. This paper describes a series of validation studies that were performed to confirm that, despite their inherent simplifications, discrete element methods can accurately capture the macro-scale response of granular materials. It is shown that, once validated, these methods can provide useful information to explain the complex response exhibited by granular materials in conventional laboratory tests.

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A three-dimensional discrete element model using arrays of ellipsoids

Cited by 323 publications

References 0 publications

The influence of inter-particle friction and the intermediate stress ratio on soil response under generalised stress conditions

The influence of inter-particle friction and the intermediate stress ratio on soil response under generalised stress conditions

An analysis of the triaxial apparatus using a mixed boundary three-dimensional discrete element model

Experimental Validation of Particle-Based Discrete Element Methods

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