Increasingly, researchers are recognizing the importance of structure and fabric on the behavior of granular assemblies. X-ray computed tomography (XCT) can be used to generate three-dimensional images of particulate structure and similarly, the discrete element method (DEM) can be used to simulate the behavior of these assemblies at the scale of individual particles. We can use the same approach to quantiy the structure of assemblies from XCT scanning and DEM simulations. Algorithms for this quantification are provided below.

Note that Section 1 (Make image) is only necessary for the case of spherical particles for which centroids and radii are known. Three dimensional image arrays are constructed from a list of particle locations. If the three dimensional image stacks already exist (e.g., from XCT), then Section 1 is not necessary.

      1.   Make image

             1.1   Algorithm to generate binary images

             1.2   Image visualization

     2.    Local space quantification

             2.1   Global Void ratio

             2.2   Get Centroid Points of each particle

             2.3   Local void ratio distribution

     3.    Particle characteristics

             3.1.  Mass of center

             3.2.  Sphericity

             3.3.  Moment of Inertia

             3.4.  Ellipsoid Fitting

             3.5.  Particle Orientation

             3.6.  Grain size distribution

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