Study of the Wall Effect on Particle Packing Structure Using X-ray Micro Computed Tomography

Suzuki, Michitaka; Shinmura, T.; Iimura, Kenji; Hirota, Mitsuaki

doi:10.1163/156855208x293817

Cited by 92 publications

(40 citation statements)

References 9 publications

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“…7 shows the translational order results for l ≥ 5. The results for l ≤ 5 are less reliable since the number of particle relations is too limited for a sound statistical analysis, and furthermore finite size and wall effects play an important role [18,20,27,28]. Two outliers can be observed in Fig.…”

Section: Resultsmentioning

confidence: 94%

Random packing of digitized particles

Korte

Brouwers

2013

Powder Technology

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a b s t r a c t a r t i c l e i n f oThe random packing of regularly and irregularly shaped particles has been studied extensively. Within this paper, packing is studied from the perspective of digitized particles. These digitized particles are developed for and used in cellular automata systems, which are employed for the simple mathematical idealizations of complex systems in physics, chemistry and engineering [S. Wolfram, Rev. Mod. Phys. 55, 601-644 (1983)]. In the present paper, the random packing of digitized particles is studied using the packing routines 561-583 (1990)]. It is shown that the packing of digitized particles is comparable to spheres, when taking into account the specific properties of digitized particles.

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Section: Resultsmentioning

confidence: 94%

Random packing of digitized particles

Korte

Brouwers

2013

Powder Technology

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“…This can be related to a possible wall type effect, in which granular particles near a rigid wall boundary show higher porosity. For a granular material, the distance over which the local porosity is affected was estimated to be about 4-5 average particle size diameters from a vertical sample wall [42]. However, for fibre-reinforced soils, De Larrard [43] estimated the perturbed zone from the face of rigid cylindrical fibres mixed with a granular soil (having an average particle size diameter of the same order of magnitude of the fibre diameter) to be much smaller, about 10% of the average particle size.…”

Section: Sample Porosity Assessmentmentioning

confidence: 99%

3D fibre architecture of fibre-reinforced sand

et al. 2017

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The mechanical behaviour of fibre-reinforced sands is primarily governed by the three-dimensional fibre architecture within the sand matrix. In laboratory, the normal procedures for sample preparation of fibre-sand mixtures generally produce a distribution of fibre orientations with a preferential bedding orientation, generating strength anisotropy of the composite's response under loading. While demonstrating the potential application of X-ray tomography to the analysis of fibre-reinforced soils, this paper provides for the first time a direct experimental description of the three-dimensional architecture of the fibres induced by the laboratory sample fabrication method. Miniature fibre reinforced sand samples were produced using two widely used laboratory sample fabrication techniques: the moist tamping and the moist vibration. It is shown that both laboratory fabrication methods create anisotropic fibre orientation with preferential sub-horizontal directions. The fibre orientation distribution does not seem to be affected by the concentration of fibres, at least for the fibre concentrations considered in this study and, for both fabrication methods, the fibre orientation distribution appears to be axisymmetric with respect to the vertical axis of the sample. The X-ray analysis also demonstrates the presence of an increased porosity in the fibre vicinity, which confirms the assumption of the "stolen void ratio" effect adopted in previous constitutive modelling. A fibre orientation distribution function is tested

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“…We can suspect, however, that this value is strongly influenced by the so-called wall effect. The container wall affects a local packing structure of particles and the porosity near the wall is higher than in the centre of the container [28]. This decreases the value of the average bulk density calculated for the powder specimen.…”

Section: Simulation Of Powder Compaction In a Cylindrical Diementioning

confidence: 98%

Discrete element simulation of powder compaction in cold uniaxial pressing with low pressure

et al. 2015

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This paper presents numerical studies of powder compaction in cold uniaxial pressing. The powder compaction in this work is considered as an initial stage of a hot pressing process so it is realized with relatively low pressure (up to 50 MPa). Hence the attention has been focused on the densification mechanisms at this range of pressure and models suitable for these conditions. The discrete element method employing spherical particles has been used in the numerical studies. Numerical simulations have been performed for two different contact models-the elastic Hertz-Mindlin-Deresiewicz model and the plastic Storåk-ers model. Numerical results have been compared with the results of laboratory tests of the die compaction of the NiAl powder. Comparisons have shown that the discrete element method is capable to represent properly the densification mechanisms by the particle rearrangement and particle deformation.

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Study of the Wall Effect on Particle Packing Structure Using X-ray Micro Computed Tomography

Cited by 92 publications

References 9 publications

Random packing of digitized particles

Random packing of digitized particles

3D fibre architecture of fibre-reinforced sand

Discrete element simulation of powder compaction in cold uniaxial pressing with low pressure

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