A corner preserving algorithm for realistic DEM soil particle generation

An efficient particle clump generation algorithm for use in discrete element methods (DEMs) was developed to simulate actual particles in a granular specimen. The algorithm requires many fewer circles than existing methods, particularly for angular particles. The procedure is a logical extension of a computational method for determining the classic Wadell particle roundness in which circles are fitted to the corners of particles. Hence, the new method perfectly preserves the location, size and shape of particle corners and is appropriately termed the corner preserving algorithm. The remaining perimeter of the particle, which includes concave and flat sections, is fitted with non-corner circles. Unlike earlier methods, the corner preserving algorithm requires only a single control parameter to generate the circles. This parameter is the ratio of the clump area to the original particle area, AR. An algorithm seeks a corresponding optimum clump roughness that achieves the user-prescribed AR. The method can easily be incorporated in existing soil particle characterization systems in which binary images or even images of particle assemblies are produced. Examples illustrate the simplicity and advantages of the corner preserving algorithm for DEM clump generation.