• 한국CDE학회논문집
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• 제21권2호
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• pp.143-150
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• 2016

In shipbuilding, hull assemblies are manufactured by welding. The thermal deformation caused by the welding produces shape deformation. Counter-deformed design methods have been used in shipyards to cope with the weld-induced deformation of ship assembles. Finite element methods (FEMs) are frequently used to estimate welding distortion in the counter-deformed design. For the estimation of welding distortion, producing uniform rectangular elements is required to enter thermal loads on the welding line and obtain accurate analysis results. In this paper, a new automatic mesh generation method is proposed for prediction of welding deformation in FEM. Meshes are constructed for test cases to demonstrate the feasibility of the proposed mesh generation method.

• 한국전산구조공학회논문집
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• 제13권3호
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• pp.329-336
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• 2000

임의의 체눈 모양에서 어떤 절점에서 출발하여 출발한 절점으로 되돌아 오는 최단 경로를 탐색함으로써 2차원 유한요소의 연결관계를 자동추출할 수 있는 방법을 개발하였다. 한 절점에서 가능한 여러 경로 중에서 가능성이 큰 경로만을 탐색하게 하였고 추출된 경로에 대하여 요소로서의 유일성 및 적합성을 검사하였다. 제안된 방법이 완전함을 증명하였으며 예제를 통하여 일반적인 자동발생 기능의 적용이 어려운 체눈 모양에 대해서도 정확하게 요소를 추출할 수 있음을 보였다.

• 한국전산구조공학회논문집
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• 제15권1호
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• pp.33-42
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• 2002

본 연구에서는 3차원 곡면의 매개변수식 기하 표현법과 계층적/관계형 자료 구조를 이용하여 3차원 터널을 자동으로 모델링할 수 있는 방안을 제시한다. 매개변수식 기하 표현법과 계층적/관계형 자료 구조의 이용은 3차원 터널 표현의 일반화와 확장성을 제공하며 해석을 위한 터널 구조의 특성을 정확하게 처리할 수 있게 한다. 그리고 터널 곡면의 곡률 특징을 이용하여 2차원 요소망 생성 알고리즘을 사용하여 3차원 요소망을 자동으로 생성할 수 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1153-1156
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• 2002

In this parer, a high quality mesh generation method by using interval arithmetic is proposed. In the proposed method, the variance of a tangent vector at the point is considered by the automatic differentiation. From the variance, sampling points on the surface are judged whether it is adequate or not, which is calculated by the interval arithmetic. Then Delaunay triangulation is performed to the obtained sampling points, and a set of meshes is generated. The proposed method is hard to overlook the local variation of surfaces.

• 한국해양환경ㆍ에너지학회지
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• 제16권2호
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• pp.130-137
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• 2013

더욱 정확한 수치 해석이 필요하면 할수록, 해석하고자 하는 구조물 상의 절점과 요소를 적절하게 배치하는 것이 중요하게 된다. 본 연구에서는 천해영역에서 구조적인 이점과 경제성의 두 가지 장점을 가지고 있는 원형 단면의 하부 구조물에 대한 3차원 삼각 Shell 요소 생성기법을 개발하였다. 높이와 형태와 같은 상세한 데이터를 입력하여 제어하는 것에 의해 기초와 타워를 다양한 유한요소 조건에서 고려할 수 있도록 하였다. 또한 기존의 3차원 Delaunay 삼각요소분할법을 사용한 결과의 수치와 비교, 검증하였으며, 현재 제안되어진 기초와 하부구조물에 적용한 요소 분할의 예를 들었다. 본 연구의 결과는 현존하거나 제안되어진 풍력 터빈의 기초부와 타워의 제원에 대해 다양하게 적용될 수 있을 것이라 사료된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.269-274
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• 2001

In order to reduce trial-and-errors in the die design and production, CAE systems for analysis of stamping tools have been introduced at the initial design stage recently. For optimal design, the CAE engineers may need to correct the meshes generated by automatic mesh generation programs. However, they may need help of CAD engineers as they are usually not skilled in manipulation of CAD systems. In order to get around these problems, automatic shell mesh modification method is proposed, which utilizes existing CAD/CAE package (in this study, I-DEAS) without user interaction. The developed method and optimization techniques are applied to a stamping die rounding optimization problem. The optimization results show that the manpower and the time required at virtual tryout can be reduced by using the developed systems.

• 소성∙가공
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• 제13권7호
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• pp.614-622
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• 2004

A new approach for the automatic elimination of free edges in the finite element model for the analysis of sheet metal forming processes is presented. In general, the raw finite element model constructed from an automatic mesh generator is not well suited for the direct use in the downstream forming analysis due to the many free edges which requires tedious time consuming interactive graphic operations of the users. In the present study, a general method for the automatic elimination of free edges is proposed by introducing a CAD/CAE hybrid method. In the method a trimmed parametric surface is generated to fill the holes which are orginated from the free edges by using the one step elastic finite element analysis. In addition, mesh generation algorithm is suggested which can be used in the general trimmed surface. In order to verify the validity of the proposed method, various examples including actual automobile sheet metal parts are given and discussed.

• 한국CDE학회논문집
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• 제4권2호
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• pp.153-161
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• 1999

An atomatic mesh generation scheme with unstructured quadrilateral elements on trimmed surfaces has been developed. Trimmed surfaces are often encountered in modeling of structures with complex shapes such as aircrafts, automobile structures, pressure vessels and etc. For unstructured mesh generation with quadrilateral elements, a domain decomposition algorithm employing loop operators has been used. Mesh generation on trimmed surface is performed in three steps. First, trimmed surfaces with holes or cuts are transformed to th largest projection planes in which the meshes are constructed. The constructed meshes are transformed to the u-v parametric plane and then finally to the original 3D surfaces. Th exact locations of holes or cuts in projection planes are determined by the Newton-Raphson method. Sample meshes are constructed to demonstrate the effectiveness of the proposed algorithm.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.419-420
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• 2006

This paper deals with a hex-dominant mesh generation using an advancing front method for three-dimensional geometries. Hexahedral and prismatic meshes are generated inwardly by offsetting from initial boundary mesh. When the meshes intersect with each other after offsetting, overlapped meshes are improved by node relocation method. In order to generate conforming mesh, pyramid elements are inserted between hexahedral and tetrahedral elements. Sample meshes fur several geometries are presented and analized to demonstrate the effectiveness of the proposed algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권11호
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• pp.3121-3144
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• 2023

As interest in the metaverse has grown, there has been a demand for avatars that can represent individual users. Consequently, research has been conducted to reduce the time and cost required for the current 3D human modeling process. However, the recent automatic generation of 3D humans has been focused on creating avatars with a realistic human form. Furthermore, the existing methods have limitations in generating avatars with imbalanced or unrealistic body shapes, and their utilization is limited due to the absence of datasets. Therefore, this paper proposes a new framework for automatically transforming and creating stylized 3D avatars. Our research presents a definitional approach and methodology for creating non-realistic character avatars, in contrast to previous studies that focused on creating realistic humans. We define a new shape representation parameter and use a deep learning-based method to extract character body information and perform automatic template mesh transformation, thereby obtaining non-realistic or unbalanced human meshes. We present the resulting outputs visually, conducting user evaluations to demonstrate the effectiveness of our proposed method. Our approach provides an automatic mesh transformation method tailored to the growing demand for avatars of various body types and extends the existing method to the 3D cartoon stylized avatar domain.