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

Abstract

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 three-dimensional (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.