• 한국CDE학회논문집
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• 제11권2호
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• pp.138-147
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• 2006

A systematic approach to tetrahedral element or mesh generation, based on an advancing-front method and an optimal triangular mesh generation technique on the surface, is presented in this paper. The possible internal nodes are obtained by the octree-decomposition scheme. The initial tetrahedral mesh system is constructed by the advancing-front method and then it is improved by the quality improvement processes including mesh swapping and nodal smoothing. The approach is evaluated by investigating the normalized length, the normalized volume, the dihedral angle and the normalized quality

• 한국CDE학회논문집
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• 제9권1호
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• pp.27-34
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• 2004

A tetrahedral mesh generation scheme using 3-D operators has been presented. The proposed scheme employs new 3-D operators such as rearranging and modified finishing operators in addition to the previous trimming, wedging, digging, splitting and finishing operators. These new operators have been introduced in order to increase the stability of mesh generation process. Check processings with surrounded element edges and faces have also been optimized by employing a searching algorithm. Sample meshes are constructed to demonstrate the mesh generating capability of the proposed algorithm.

• 한국정밀공학회지
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• 제21권3호
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• pp.91-99
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• 2004

An unstructured tetrahedral mesh generation algorithm has been presented. In order to construct better meshes in interior region by using an advancing front technique, a connecting operator and a local finishing operator II have been developed in addition to the existing operators. Before applying digging operators that generate new nodes inside of a meshing region, a connecting operator is employed that uses existing nodes which satisfy certain conditions for producing well-conditioned elements. The local finishing operator II is introduced to terminate the meshing process more flexibly on remaining subregions. With these new operators, tetrahedral meshing process becomes more robust and good quality of meshes are constructed.

• 대한기계학회논문집A
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• 제29권5호
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• pp.671-679
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• 2005

A method of generation boundary layer mesh has been presented. This paper describes the generation of semi-unstructured prismatic/tetrahedral meshes for three-dimensional geometries with thin thickness. By of fretting of surface triangle elements prismatic/tetrahedral meshes are generated and using the node relocation method of this research intersected meshes can be efficiently improved. Finally tetrahedral meshes are automatically generated at the rest of the domain. Sample meshes are constructed to demonstrate the mesh generating capability of the proposed algorithm.

• 한국CDE학회논문집
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• 제8권1호
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• pp.41-47
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• 2003

In this paper, a tetrahedral mesh generation algorithm which uses a grid based method for interior region and an advancing front method for outer surface region is proposed. In order to apply an advancing front method for outer region of an object, a new operator so called a hole operator has been developed to handle multiple shells. With this grid based approach in the interior region, more stable and uniform meshes can be constructed especially in the interior region.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1605-1608
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• 2003

A unstructured tetrahedral mesh generation algorithm has been presented. To make better meshes in interior region using an advancing front technique, a connecting operator has been developed in addition to the existing operators. Before applying digging operators that generate new nodes inside of a meshing region, a connecting operator is employed that uses existing nodes which satisfy certain conditions for producing well-conditioned elements if possible. By introducing this new operator, tetrahedral meshing process becomes more robust and produces better quality of meshes.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.209-214
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• 2005

In this paper, finite element simulation of three-dimensional bulk metal forming processes is performed by an automated adaptive tetrahedral mesh generation scheme. A dynamic data exchange scheme is employed between tetrahedral mesh generator and forging simulator to minimize user intervention. Both number of elements and density distributions are controlled by the octree technique. The presented approach is applied to automatic forging simulation in order to evaluate the efficiency of the developed schemes and the simulation results are compared with $DEFORM^{TM}$.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.865-870
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• 2004

This paper describes the generation of chordal surface for various shell structures, such as automobile bodies, plastic injection mold components and shell metal parts. After one-layered tetrahedral mesh is generated by an advancing front algorithm, the chordal surface is generated by cutting a tetrahedral element. It is generated one or two elements at a tetrahedral element and the chordal surface is composed with triangular or quadrilateral elements. This algorithm has been tested on several models with rib structure.

• 대한기계학회논문집
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• 제18권12호
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• pp.3159-3174
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• 1994

A simple octree encoding algorithm based on a tetrahedron root has been developed to be used for fully automatic generation of three dimensional finite element meshes. This algorithm starts octree decomposition from a tetrahedron root node instead of a hexahedron root node so that the terminal mode has the same topology as the final tetrahedral mesh. As a result, the terminal octant can be used as a tetrahedral finite element without transforming its topology. In this part(I) of the thesis, an efficient algorithm for the tetrahedron-based octree is proposed. For this development, the following problems have been solved, : (1) an efficient data structure for storing the octree and finite elements, (2) an encoding scheme of a tetrahedral octree, (3) a neighbor finding technique for the tetrahedron-based octree.

• 대한기계학회논문집
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• 제19권3호
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• pp.647-660
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• 1995

Given the tetrahedron-based octree approximation of a solid as described in part(I) of this thesis, in this part(II) a systematic procedure of 'boundary moving' is developed for the fully automatic generation of 3D finite element meshes. The algorithm moves some vertices of the octants near the boundary onto the exact surface of a solid without transforming the topology of octree leaf elements. As a result, the inner octree leaf elements can be used as exact tetrahedral finite element meshes. In addition, as a quality measure of a tetrahedral element, 'shape value' is propopsed and used for the generation of better finite elements during the boundary moving process.