Now showing 1 - 3 of 3
  • Publication
    Investigation of particle breakage under one-dimensional compression of sand using X-ray microtomography
    (Canadian Science Publishing, 2020-05-05) ; ; ;
    Particle breakage alters particle-scale properties of granular soils including particle size, shape, and contact conditions, and changes macroscale properties including soil compressibility, shear strength, and permeability. This study monitors the crushing of natural quartz sands under one-dimensional compression with in situ X-ray tomography, i.e., X-ray scans during loading. We use the assembly-scale and particle-scale images to characterize particle failure patterns, e.g., chipping, major splitting, and comminution. Image processing and analysis enable us to determine the failure patterns around the yield stress, and the influence of initial density and particle morphology on the particle survival probability. We further quantify the degree of particle breakage with fractal dimension, breakage factor, and specific surface. Particle shape and coordination number both show a scale-dependent evolution pattern.
      326Scopus© Citations 56
  • Publication
    A simple method for particle shape generation with spherical harmonics
    (Elsevier, 2018-05-01) ; ;
    The increasing interest in particle shape influence on granular mechanics necessitates a fast and robust particle shape generation method. We describe a new approach based on rotation-invariant spherical harmonic (SH) analysis. The core of this method is to construct morphology features at various length scales and superimpose them together to form the overall morphology. This method uses four rotation-invariant SH factors to construct SH coefficient matrices. We quantify particle shape at form, roundness, and compactness to establish the linkage between SH factors and traditional shape parameters. It is found that SH factors effectively control particle features at different scales. This method has a great potential to facilitate the research on granular mechanics considering particle shape effects.
      261Scopus© Citations 58
  • Publication
    Particle shape quantification using rotation-invariant spherical harmonic analysis
    (ICE Publishing, 2017-06-01) ; ;
    A three-dimensional (3D) particle surface can be mathematically represented by a spherical harmonic (SH) coefficient matrix through surface parameterisation and SH expansion. However, this matrix depends on not only the particle shape but also the size, position and orientation. This study adopts a rotation-invariant analysis to explore the relationship between SH coefficient matrices and particle shape characteristics. Particle shapes are quantified at different scales (i.e., form, roundness and compactness). These methods are applied to two groups of particles (i.e., Leighton Buzzard sand (LBS) particles and LBS fragments) with distinct shape features. By using rotation invariants, the multi-scale nature of particle shape is illustrated, and two novel shape descriptors are defined. The results in this paper serve as a starting point for the generation of particle shapes with prescribed shape features using spherical harmonic.
      262Scopus© Citations 27