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9 W H I T E P A P E R 3.4 Discrete breakage of shells Another form of particle representation in Rocky is shell particle shape, which is used to represent materials with relatively small thickness, such as leaves, chips, fabric, or paper. Breakage of such material is undesired in some applications, like in potato chip seasoning, as shown in Figure 6. On the other hand, breakage is desired in other operations to reduce the particle size, such as in wood chip material handling for pulp and paper manufacturing processes. Lawn mowing is also a good example of an application where the shell particle model can be used combined with the breakage model to increase equipment efficiency. 3.5 Discrete breakage of custom shaped particles Other unique shapes, such as glass bottles moving on a conveyor belt, pharmaceutical tablets inside a tablet coater, or even manufacturing bricks and roof tiles can be used as particles during a simulation in Rocky. Figure 7 is an example of a glass bead breakage simulation in which the crack propagation can be seen. Simulating such particle shapes is a highly complex problem, given the importance of capturing correct particle motion, which is driven by the moment of inertia and hence the particle shape. This challenge can be easily accommodated in Rocky. Figure 6: Simulation of potato chips in a seasoning drum including the analysis of chip breakage.

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