A new Discrete Element (DE) method has been developed to model the dynamic behaviour of an assembly of axi-symmetrically shaped fruits. In the new method, which we term the “multi-element” method, model fruits (taken here to also include vegetables, grains and nuts) are comprised of overlapping spheres whose centres are fixed in position relative to each other along the major axis of symmetry of the fruit. Element spheres are inscribed in the real fruit shape such that the diameter of the spheres varies with the fruit surface contour. Contact detection between two neighbouring model fruits is achieved using standard DE methods for two single spheres. The method thus takes advantage of the speed and accuracy of contact detection associated with standard DE schemes employing single spheres. The scheme is well suited to numerical modelling of post-harvest operations such as hopper filling and emptying, conveying, sorting and object manipulation where the produce are discrete entities with relatively round smooth surfaces.

A new Discrete Element (DE) method has been developed to model the dynamic behaviour of an assembly of axi-symmetrically shaped fruits. In the new method, which we term the “multi-element” method, model fruits (taken here to also include vegetables, grains and nuts) are comprised of overlapping spheres whose centres are fixed in position relative to each other along the major axis of symmetry of the fruit. Element spheres are inscribed in the real fruit shape such that the diameter of the spheres varies with the fruit surface contour. Contact detection between two neighbouring model fruits is achieved using standard DE methods for two single spheres. The method thus takes advantage of the speed and accuracy of contact detection associated with standard DE schemes employing single spheres. The scheme is well suited to numerical modelling of post-harvest operations such as hopper filling and emptying, conveying, sorting and object manipulation where the produce are discrete entities with relatively round smooth surfaces.

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