A multi-sphere based modelling method for maize grain assemblies

- The shapes of maize grains are divided into four kinds of shapes.
- There exists a functional relationship between dimensions of maize grain.
- The models of maize grain with different sub-spheres are compared.

In this paper, the geometric shape, dimension parameters and density of maize grains were studied to establish a DEM analysis model of maize assemblies. According to the results, the shape of maize grains of the same variety can be divided into wide wedge, narrow wedge, ellipsoidal-conical and irregular shapes. Amongst these shapes, the quantity of wide wedge and narrow wedge shapes accounts for more than 90% of the total. When modelling maize assemblies, wedge shaped maize can be chosen to establish a geometric model with the upper base defined as the main dimension and other dimensions calculated based on the relationship with the main dimension. The geometric model of single maize grains was established using a Multi-Sphere (MS) model. This analysis model of maize grain is acceptable for scenarios with 14-16 sub-spheres. On the basis of this work, 2 varieties of maize grains are used as examples. The feasibility and validity of the modelling method of maize assemblies and single maize grains are preliminarily verified through comparison of experimental and simulated data to determine repose angles and bulk density.

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