| Summary: | 碩士 === 國立中央大學 === 土木工程研究所 === 97 === Many materials in the world are discrete material, such as sand and rocks which always get irregular shape. It is proper to discrete element method for numerical simulation. The main idea of this thesis is combination the achievement of “Numerical Simulation for Granular Assemblies Egg-shaped Particle” and ” Numerical Simulation for Granular Assemblies with Mixed 3D Rigid Body ”. In addition, add the pre-processor code to arrange the position of the particles and prevent the particle overlap when the code assigns the position of the particle. In the post-processor part, the animate code is expanded the polyhedron block.
Actually, the main idea of this research is accomplishment of the contact detection between the egg-shaped particle and polyhedron block. The egg-shaped particle is formed by four-circle approximation method so as to form the ellipsoid. The ellipsoid only is the special case of the egg-shaped particle. Thus the “Numerical Simulation for Granular Assemblies with Mixed 3D Rigid Body” is more generalized. The egg-shaped particle would contact with the polyhedral block in these three ways: (1) ball- vertex (2) curve-vertex (3) ball-edge (4) curve-edge (5) ball-plane (6) curve-plane. When the egg-shaped particle contact with the edge of the polyhedron block or the plane of the polyhedron block, it could detect the out range of the polyhedron block as contact. So it must be to add the mechanism to detect the contact point inside or outside. After finishing the code, there are three examples to test the correction of the code. (1) projectile of the egg-shaped particle (2) the linear momentum equilibrium of the collision of polyhedron block and the egg-shaped particle (3) friction test. This research simulates the Brazil nut effect. After shaking the particle assemblies , the bigger particle would motion to the upper of the particle assemblies. Many examples occur the Brazil nut effect in the world. For example, the mud slide is. The bigger rocks would appear upper portion of the rocks.
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