The geometry of convex polyhedra is described by a set of half spaces. This geometry representation is used in the discrete element method to model polyhedral particles. An algorithm for contact detection and the calculation of the interaction forces for these particles is presented. Finally the presented model is exemplified by simulating the particle flow through a hopper.

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Wire sawing is one of the most prominent technologies for producing solar wafers. In the following paper a numerical model for the simulation of the wire sawing process at microlevel using the discrete element method is presented. The abrasive particles are represented by convex polyhedra. Based on the contact forces on the ingot, local material removal rates are calculated. These local material removal rates are then used to update the shape of the ingot in a stepwise simulation. The model allows for detailed analysis of the influence of different parameters on the micromechanical processes during wire sawing. In particular the influence of wire speed, lapping pressure, particle concentration, particle size, particle shape and debris on the sawing process is investigated. In a post-processing macroscopic process characteristics like kerf width, depth of surface cracks or sawing rate are calculated. Thus, the processes at the microlevel are related to the macroscopic process characteristics, which are of interest when applying wire sawing in practice.