Structural and Micromechanical Properties of Ternary Granular Packings: Effect of Particle Size Ratio and Number Fraction of Particle Size Classes.

Joanna Wiącek,Mateusz Stasiak,Jalal Kafashan

doi:10.3390/ma13020339

Abstract

The confined uniaxial tests of packings with discrete particle size distribution (PSD) were modeled with the discrete element method. Ternary packings of spheres with PSD uniform or nonuniform by number of particles were examined in three-dimensional (3D) system. The study addressed an effect of the particle size ratio and the particle size fraction on structural and micromechanical properties of mixtures. A study of packing structure included porosity and coordination numbers, while the investigation of micromechanical properties included distribution of normal contact forces and stress transmission through the packing. A micro-scale investigation of the effect of particle size ratio on structure and mechanics of the ternary packings revealed a strong relationship between the properties of sample and the value of parameter till its critical value was reached. A further increase in particle size ratio did not significantly affect properties of packings. Contrary to the porosity and coordination numbers, the partial stresses were highly affected by the fraction of particle size classes in ternary mixtures. The contribution of the partial stress into the global stress was determined by number fraction of particles in packings with small particle size ratio, while it was mainly determined by particle size ratio in packings with small particle size ratio.

Highlights

Ternary mixtures, after binary ones, are the simplest polydisperse granular packings, which exhibit interesting and unexplained behavior
A number of these studies has been devoted to the analysis of properties of ternary granular mixtures, they mainly included an analysis of the packing density and the coordination number, the most important parameters in describing the geometrical arrangement of particles in grain bedding [1,9,10,11,12]
244, the least anumerous large particles transmitted the largest stress that in particle size.and. These indicate huge significance of the difference between sizes of particles decreased with a decrease in particle size. These results indicate a huge significance of the difference on contribution of partial stress into a global stress in ternary granular packings

Summary

Introduction

After binary ones, are the simplest polydisperse granular packings, which exhibit interesting and unexplained behavior. An examination of their properties is very important and necessary because the particulate systems composed of three particle size fractions are commonly used in many branches of industry (e.g., chemistry, pharmacy, and metallurgy). In 1986, Stovall et al [11] proposed a linear density model of multicomponent systems, which was applicable inter alia for binary and ternary mixtures It assumed that the specific volume of the mixture was a linear function of the volumetric fractions of the individual size classes. The authors proved that the new method is applicable for binary and ternary mixtures of sand

Methods

Results

Conclusion