Critical assessment of two approaches for evaluating contacts between super-quadric shaped particles in DEM simulations

Validation of a stochastic digital packing algorithm for porosity prediction in fluvial gravel deposits

“…Traditional ways to construct an irregular particle require the user to place spherical elements within a meshed polyhedral body (e.g., Wang et al, 2007;Matsushima et al, 2009;Ferellec and McDowell, 2010;Fukuoka et al, 2013), which consumes high computational costs with large numbers of components (spheres) involved (Hubbard, 1996;Song et al, 2006). Although techniques using 3D polyhedral (Latham et al, 2001) or continuous superquadric functions (Williams and Pentland, 1992;Lu et al, 2012) provide a straightforward way to generate irregular particle shapes, complex contact-detection algorithms are needed, leading to deterioration in simulation speed as particle complexity increases (Johnson et al, 2004). In order to overcome these difficulties, a stochastic digital packing algorithm was developed (Jia and Williams, 2001).…”

Determining the shape of agricultural materials using spherical harmonics

“…As the development of SHM for its application in DEM is still in progress, the number of direct contributions that use SHM in DEM is limited (Garboczi, 2011;Garboczi and Bullard, 2013;Zhou et al, 2015). In this regard, two strategies can be followed to incorporate SHM into DEM codes: (1) development of shape-independent universal models with the use of continuous function representations (CFR) to analytically describe real shapes (Lu et al, 2012), or (2) development of shape-specific DEM models such as a sphero-polyhedrals or MS using approximated SH expressions.…”

“…Contact between analytically well-defined shapes is basically restricted to super-ellipsoidal (Wellmann et al, 2008) or super-quadric shaped particles (Lu et al, 2012).…”

“…Approximated SHM representation for use in DEM As mentioned above, there are two potential strategies concerning the use of SH in DEM. The first strategy concerns the use of continuous or discrete representation functions (Johnson and Williams, 2009;Lu et al, 2012;Garboczi and Bullard, 2013), and the second concerns the development of specific models for shapes such as ellipsoids or cylinders. In each case, specific data and software implementations will be required.…”

A discrete element model (DEM) for predicting apple damage during handling

“…Particles are usually spherical in shape but more detailed geometrical representations may be achieved through the use of polygons, implicit surfaces and parametric surfaces (Wachs et al, 2012., Fraige, et al, 2008., Hogue & Newland, 1994& Lu et al, 2012.…”