| Summary: | 碩士 === 國立中央大學 === 機械工程學系 === 104 === The quality of solid meshes affects the accuracy of the analysis considerably in mold flow analysis. Three kinds of solid meshes typically used in numerical analysis are: tetrahedron, prism, and hexahedron meshes. The advantage of tetrahedron meshes is that the meshes can be generated automatically. However, its disadvantages are that the mesh quality may not be satisfied and it is difficult to control the number of mesh layers. The advantage of prism and hexahedron meshes is that the mesh quality is much better than that of tetrahedron meshes. But, the disadvantage is that it is difficult to generate these types of meshes automatically. To generate prism and hexahedron meshes of high quality, it still relies on manual work to plan and edit the solid meshes. The purpose of this study is to analyze the method of solid mesh generation and propose a framework for generating prism and hexahedron meshes manually, especially for CAD models with fillets and bosses. When fillets appear, the shape of the solid meshes is usually deformed owing to long and narrow shape of the fillets. To improve the mesh quality for CAD models with fillets, we developed six kinds of mesh templates for fillets. The principle of the proposed mesh templates is to generate hexahedron meshes for all kinds of fillets. The number and size of meshes on each template can be adjusted in accordance with actual shape and size of fillets. As for bosses, they can be divided into two parts: tube and rib. The principle of solid mesh generation for bosses is to generate prism and/or hexahedron meshes along the direction of the thickness, and control the mesh layer along that direction. Finally, several CAD models are employed to generate prism and hexahedron meshes by using the proposed mesh generation method. A comparison of the meshes obtained using the proposed method and current technique is provided also. The proposed mesh generation concept can be used for developing automatic solid mesh generation algorithm for prism and hexahedron meshes in the future.
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