• Transactions of Materials Processing
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• v.9 no.2
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• pp.140-151
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• 2000

The finite element mesh approach for tool surface description is applied effectively to analyze sheet metal stamping processes. To improve the mesh quality and the stability of the mesh generation process, a gybrid method based on the grid approach and the Delaunay triangulation is proposed in the present work. In the present study, a general method for the mathematical description of arbitrarily shaped tool surface is proposed by introducing the parametric surface approach. A polynomial function employed to describe the base parametric surface and the boundary curves are defined to describe arbitrary three-dimensional trimmed surfaces. To verify the validity of the proposed method, automatic mesh generation is carried out for some shosen complicated parts including actual automotive panel.

• Korean Journal of Computational Design and Engineering
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• v.10 no.1
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• pp.61-69
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• 2005

In the global ship structure and vibration analysis, the FE(finite element) analysis model is required in the early design stage before the 3D CAD model is defined. And the analysis model generation process is a time-consuming job and takes much more time than the engineering work itself. In particular, ship structure has too many associated structural members such as stringers, stiffness and girders etc. These structural members should be satisfied as the constraints in analysis modeling. Therefore it is necessary to support generation of analysis model with satisfying these constraints as an automatic manner. For the effective support of the global ship analysis modeling, a method to generate analysis model using initial design information within ship design process, that hull form offset data and compartment data, is developed. In order to easily handle initial design information and FE model information, flexible data structure is proposed. An automatic quadrilateral mesh generation algorithm using initial design information to satisfy the constraints imposed on the ship structure is also proposed. The proposed data structure and mesh generation algorithm are applied for the various type of vessels for the usability test. Through this test, we have verified the stability and usefulness of this system including mesh generation algorithm.

• Transactions of Materials Processing
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• v.13 no.4
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• pp.334-341
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• 2004

In this study, a remeshing algorithm adapted to the mesh density map using the Delaunay mesh generation method is developed. In the finite element simulation of forging process, the numerical error increases as the process goes on because of discrete property of the finite elements and distortion of elements. Especially, in the region where stresses and strains are concentrated, the numerical error will be highly increased. However, it is not desirable to use a uniformly fine mesh in the whole domain. Therefore, it is necessary to reduce the analysis error by constructing locally refined mesh at the region where the error is concentrated such as at the die corner. In this paper, the point insertion algorithm is used and the mesh size is controlled by using a mesh density map constructed with a posteriori error estimation. An optimized smoothing technique is adopted to have smooth distribution of the mesh and improve the mesh element quality.

• 한국전산유체공학회:학술대회논문집
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• 2001.10a
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• pp.152-156
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• 2001

Three dimensional orthogonal grid generation is able to control effectively the grid spacing near the boundaries, but there are some difficulty to meshing complex geometry. The mesh complex geometry by orthogonal grid generation method must divide block of geometry It is required a careful skill, and long time. Its also difficulty to make unstructured mesh on complex geometry. Particularly, three dimensional geometry must have more time and effort. Recently, there have been growing interests in mesh generation of complex grometry, aslike an automobile headlamp, the heart. The method of easily meshing complex geometry is resarched to solve them. We suggest octree grid into one among these methods. As octrce grid is automaticaly adapted at the boundaries by determine the level operations to control the grid spacing near the boundaries are unnecessary. In this paper we showed throe dimensional mesh generation, and heat-flow analysis on the octree mesh.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.2
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• pp.553-563
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• 1996

An algorithm for automatic mesh generation of two-dimensional arbitrary planar domain is proposed by using Delaunay triangulation algorithm. An efficient algorithm is proposed for the construction of Delaunay triangulation algorithm over convex planar domain. From the definition of boundary, boundary nodes are first defined and then interior nodes are generated ensuring the Delaunay property. These interior nodes and the boundary nodes are then linked up together to produce a valid triangular mesh for any finite element analysis. Through the various example, it is found that high-quality triangular element meshes are obtained by Delaunay algorithm, showing the robustness of the current method. The proposed mesh generation scheme has been extended to automatic remeshing, which is applicable to FE analysis including large deformation and large distortion of elements.

• Korean Journal of Computational Design and Engineering
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• v.4 no.2
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• pp.79-86
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• 1999

A general approach to automatic generation of triangular meshes on three-dimensional surfaces is presented in this paper. The approach, developed with emphasis on program generality and interface with CAD/CAM systems, is based on the double mapping method and the looping method. The double mapping method is introduced and anew splitting scheme is proposed for the looping method employed for triangular mesh generation on the parametric domain. Several application examples are given.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.8-16
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• 2007

Finite element analysis (FEA) is an effective means for the analysis of bioelectromagnetism. It has been successfully applied to various problems over conventional methods such as boundary element analysis and finite difference analysis. However, its utilization has been limited due to the overwhelming computational load despite of its analytical power. We have previously developed a novel mesh generation scheme that produces FE meshes that are content-adaptive to given MR images. MRI content-adaptive FE meshes (cMeshes) represent the electrically conducting domain more effectively with far less number of nodes and elements, thus lessen the computational load. In general, the cMesh generation is affected by the quality of feature maps derived from MRI. In this study, we have tested various feature maps created based on the improved differential geometry measures for more effective cMesh head models. As performance indices, correlation coefficient (CC), root mean squared error (RMSE), relative error (RE), and the quality of cMesh triangle elements are used. The results show that there is a significant variation according to the characteristics of specific feature maps on cMesh generation, and offer additional choices of feature maps to yield more effective and efficient generation of cMeshes. We believe that cMeshes with specific and improved feature map generation schemes should be useful in the FEA of bioelectromagnetic problems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.513-518
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• 2016

This paper presents a fast 3D mesh generation method using projection for line laser-based 3D scanners. The well-known method for 3D mesh generation utilizes convex hulls for 4D vertices that is converted from the input 3D vertices. This 3D mesh generation for a large set of vertices requires a lot of time. To overcome this problem, the proposed method takes (${\theta}-y$) 2D depth map into account. The 2D depth map is a projection version of 3D data with a form of (${\theta}$, y, z) which are intermediately acquired by line laser-based 3D scanners. Thus, our 2D-based method is a very fast 3D mesh generation method. To evaluate our method, we conduct experiments with intermediate 3D vertex data from line-laser scanners. Experimental results show that the proposed method is superior to the existing method in terms of mesh generation speed.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.55-55
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• 2003

• 한국전산유체공학회:학술대회논문집
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• 2001.10a
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• pp.157-163
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• 2001

In the present study a mesh generation program is developed for three dimensional flow analyses with complex geometry. By the present program one can define vertices using various coordinate systems and cells for finite volume approach. Rendered display of the generated mesh can be also available in both orthographic and perspective projection modes. Through perspective projection mode, one can check the quality of generated mesh by moving around inside the mesh like a virtual reality. The examples of the program execution is given in the paper.