Theoretical estimation for the volume fraction of interfacial layers around convex particles in multiphase materials

Xu, Wenxiang; Chen, Huisu; Chen, Wen; Zhu, Zhigang

doi:10.1016/j.powtec.2013.09.010

Cited by 21 publications

(5 citation statements)

References 11 publications

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“…At the microscopic scale, particulate materials are normally regarded as a three-phase composite structure, composed of the matrix, ellipsoidal grains and interfacial layers with a preconfigured constant thickness t coated around the grains. − ,− ,− Also, the surface spacing between neighboring grains is considered to be large enough to neglect the interference between adjacent interfacial layers. As an introductory example, a spheroidal grain E 1 is considered, and its size is represented by an equivalent diameter D eq1 that is defined as the diameter of a sphere having the same volume as the spheroidal grain, ,,, as given the following equation. D eq 1 = { lefttrue 2 a 1 κ 1 1 / 3 κ 1 < 1 2 a 1 κ 1 − 2 / 3 κ 1 ≥ 1 where a 1 and κ 1 are the semimajor axis and aspect ratio of the spheroid, respectively.…”

Section: Geometrical Analysismentioning

confidence: 99%

Modeling Study of the Valid Apparent Interface Thickness in Particulate Materials with Ellipsoidal Particles

Chen

et al. 2013

Ind. Eng. Chem. Res.

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When interfacial layers are viewed as a separate phase, the interface thickness plays an essential role in assessing physicomechanical properties of particulate materials. However, the actual interface thickness is difficult to determine because of the opacity of particulate materials. The apparent interface thickness obtained from sectional analysis is often overestimated, due to the irregularity of surface texture of grain that gives rise to the normal of a cross-sectional plane nonperpendicular to the grain surface. Hence, the determination of the overestimation degree between the apparent value and preconfigured value is very critical to quantify precisely the valid apparent interface thickness. The majority of previous works focused on the overestimation degree for threedimensional (3D) spherical, two-dimensional (2D) elliptical and rectangular particles, whereas little is known about 3D ellipsoidal particles. In this work, a numerical scheme is proposed to obtain the overestimation degree of the interface thickness around ellipsoidal grains. On the basis of the quantitative stereology and geometrical probability, the valid statistical mean apparent interface thickness and overestimation degree are analyzed theoretically. The deduced results show that the two values primarily subject to an unknown coefficient. A sectional analysis numerical algorithm is then implemented to derive the coefficient for an ellipsoidal grain. To test the proposed numerical model, valid theoretical data for spherical and ellipsoidal particles is selected for comparisons. Finally, by the developed numerical model, the effects of geometrical characteristics of ellipsoidal grains and the preconfigured thickness on the overestimation degree and valid apparent interface thickness are investigated in a quantitative manner.

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Section: Geometrical Analysismentioning

confidence: 99%

Modeling Study of the Valid Apparent Interface Thickness in Particulate Materials with Ellipsoidal Particles

Chen

et al. 2013

Ind. Eng. Chem. Res.

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“…On the contrary, the second approach virtually generates several models and computationally cost lower. The method of virtual fabrication for mesostructure has been broadly utilized to characterize mesoscopic structural properties [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

An integrated framework for modelling virtual 3D irregulate particulate mesostructure

Naderi

Zhang

2019

Powder Technology

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Many particulate composites show heterogenous mesoscopic structural behaviour due to a random distribution of irregular shaped particles with different sizes ranging from micro to macro scale. Accurate mesoscale models are required to represent actual geometric properties of such a composite with realistic features. In this paper, a cost-effective simulation framework is presented, which can virtually generate three-dimensional mesostructure models composed of irregulate particles with real characteristics. A MATLAB code is developed based on the Voronoi tessellation method and the splining technique. The hybrid Voronoi-spline algorithm can be programmed to control the shape and size of particles based on the experimental data. The examples demonstrated the proper adjustability of the models in accordance with the sieve analysis and shape parameters such as sphericity and roundness. The generated model as a triangulated geometry surface can be directly exported into computational analysis of materials, which uses other numerical techniques including finite element method.

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“…Thus, the ITZ is considered to be a 'weak link' when describing or predicting the macroscopic performance of cementitious composites, such as mechanical and transport properties [5][6][7][8][9][10][11][12][13][14][15][16]. To better understand the influence of the ITZ microstructure on the macroscopic performance of the composite as a whole [17], it is necessary to quantify the thickness and volume fraction of the ITZ [18][19][20]. However, the actual ITZ thickness (here denoted t) is difficult to measure because the constituents of most composites are opaque.…”

Section: Introductionmentioning

confidence: 99%

Quantification of the influences of aggregate shape and sampling method on the overestimation of ITZ thickness in cementitious materials

2018

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The microstructure of the interfacial transition zone (ITZ) surrounding the aggregate in a cementitious composite is quite different from that of the bulk matrix, because of its distinct physical nature including relatively high porosity and low rigidity. The thickness and volume fraction of the ITZ play a major role in determining the transport and mechanical behaviour of cementitious composites. However, the ITZ thickness may be overestimated when undertaking sectional plane analysis of these composites. Analysis of Platonic particles has previously shown that the sphericity of the particle is an important parameter in determining the overestimation of the ITZ thickness, but this raises the question of whether sphericity is sufficient to uniquely characterize the influence of aggregate shape. This paper investigates the influence of particle shape on overestimation of ITZ thickness for aggregate shapes which have the same sphericity values as Platonic particles; specifically, spheroids of differing geometries. A normal line sampling algorithm, which is designed to replicate the practical experimental process used in ITZ determination, is employed to obtain the apparent ITZ thickness. The influences of particle shape, sampling method and particle size distribution are investigated in terms of the overestimation of the ITZ volume fraction, and the effective diffusivity within three-phase composites, using the differential effective medium approximation.

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Theoretical estimation for the volume fraction of interfacial layers around convex particles in multiphase materials

Cited by 21 publications

References 11 publications

Modeling Study of the Valid Apparent Interface Thickness in Particulate Materials with Ellipsoidal Particles

Modeling Study of the Valid Apparent Interface Thickness in Particulate Materials with Ellipsoidal Particles

An integrated framework for modelling virtual 3D irregulate particulate mesostructure

Quantification of the influences of aggregate shape and sampling method on the overestimation of ITZ thickness in cementitious materials

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