| A discrete model of granular type materials is presented in this dissertation. The model has three submodels: the Molecular Dynamics model, the Quasi-Static Model and the Multibody Dynamics model. Each of the submodels is a valid granular material model with its own applicability limits. By combining the three submodels, a unique model with a very wide range of applicability is obtained. The model can adapt to dynamic changes in the granular system by “morphing” into the most applicable submodel.; The Multibody Dynamics model is presented first, together with the underlying equations and algorithms. The application of this model to the simulation of a shaker ball mill is presented. Two grinding models, a statistical and an analytical, are also presented.; Then, the Quasi-Static model is presented. The original Recursive Inverse Matrix Algorithm (RIMA) that enables the inverse stiffness matrix of a granular system to be maintained dynamically is presented. It is then shown how the model handles local instabilities in the system, such as slips and micro-avalanches. The application of the Quasi-Static model to the simulation of a silo is presented.; Finally, the unified model based on the original Multibody Dynamics approach is presented. The model contains the Molecular Dynamics and Quasi-Static models as submodels and uses them to represent various parts of the granular system depending on the current conditions. The application of the unified model to the simulation of hopper flow is presented. |
