Discrete element modeling with dilated particles

A new contact detection technique for discrete element modeling is described. This technique is suitable for a large family of particle shapes that are based on the dilation process from mathematical morphology. In the dilation process an arbitrary shape is dilated by placing the center of a sphere of fixed diameter at every point in the basic shape. Defining a contact between two objects in this class is equivalent to determining which spheres amongst the infinite number that compose each object is in contact. The algorithm is derived for general ellipsoidal particles and demonstrated with a series of biaxial deformation simulations using a range of ellipsoidal particle shapes.