• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.474-477
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• 2000

This paper presents an algorithm for simplification of 3D triangular mesh data, based on mesh simplification. The proposed algorithm is first attempt to segment the entire mesh into several parts using the orientation of triangles. Then simplification algorithm is applied to each segment that has similar geometric property. The proposed two step multi-resolution modeling scheme would yield better performance then conventional algorithm like edge collapse technique, since the segmentation step can give global information on the input shape. The experimental results show that the proposed algorithm is performed efficiently.

• International Journal of Naval Architecture and Ocean Engineering
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• 제4권3호
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• pp.228-240
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• 2012

Morphing is a geometric interpolation technique that is often used by the animation industry to transform one form into another seemingly seamlessly. It does this by producing a large number of 'intermediate' forms between the two 'extreme' or 'parent' forms. It has already been shown that morphing technique can be a powerful tool for form design and as such can be a useful addition to the armoury of product designers. Morphing procedure itself is simple and consists of straightforward linear interpolation. However, establishing the correspondence between vertices of the parent models is one of the most difficult and important tasks during a morphing process. This paper discusses the mesh-merging method employed for this process as against the already established mesh-regularising method. It has been found that the merging method minimises the need for manual manipulation, allowing automation to a large extent.

• Computers and Concrete
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• 제31권3호
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• pp.223-239
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• 2023

Geometric nonlinear performance simulation and analysis of complex modern buildings and industrial products require high-performance shell elements. Balancing multiple aspects of performance in the one geometric nonlinear analysis element remains challenging. We present a new shell element, flat shell DKMGQ-CR (Co-rotational Discrete Kirchhoff-Mindlin Generalized Conforming Quadrilateral), for linear and geometric nonlinear analysis of both thick and thin shells. The DKMGQ-CR shell element was developed by combining the advantages of high-performance membrane and plate elements in a unified coordinate system and introducing the co-rotational formulation to adapt to large deformation analysis. The effectiveness of linear and geometric nonlinear analysis by DKMGQ-CR is verified through the tests of several classical numerical benchmarks. The computational results show that the proposed new element adapts to mesh distortion and effectively alleviates shear and membrane locking problems in linear and geometric nonlinear analysis. Furthermore, the DKMGQ-CR demonstrates high performance in analyzing thick and thin shells. The proposed element DKMGQ-CR is expected to provide an accurate, efficient, and convenient tool for the geometric nonlinear analysis of shells.

• Architectural research
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• 제15권4호
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• pp.207-214
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• 2013

A form-finding technique is proposed for three-dimensional spatial structures. Two-step discrete finite element (FE) mesh generator based on computer aided geometric design (CAGD) is introduced and used to control the shape of three-dimensional spatial structures. Mathematical programming technique is adopted to search new forms (or shapes) of spatial structures. For this purpose, the strain energy is introduced as the objective function to be minimized and the initial volume (or the initial weight) is considered as constraint function. Numerical examples are carried out to test the capability of the proposed form-finding techniques and provided as benchmark tests.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1990년도 가을 학술발표회 논문집
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• pp.40-46
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• 1990

This paper introduces a geometric modelling system adopted in a newly developed preprocessor for finite element analysis of three dimensional structures. The formulation is characterized by hierarchical construction of structural model which consists of control points, curves, surfaces and solids. Various surface and solid modeling schemes based on blending functions and boundary representation are systematized for finite element mesh generation. The modeling system is integrated with model synthesis and operations which facilitate modelling of complex structures.

• 한국CDE학회논문집
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• 제20권2호
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• pp.104-113
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• 2015

In developing a tire, many CAE analyses are performed to make a better tire. But its meshing work is not easy, and it takes much time. One of the reasons of taking much time is that there are many overlapped geometric entities in CAD data that are modeled in CAD system by CAD engineers. In this study, we studied about the features of the overlapped geometric entities, and the method to find out and delete them. I developed a program using the proposed algorithm, and applied it in meshing tire pattern and tire case. I proved that the time in meshing a tire reduced dramatically by removing overlapped geometric entities by using the developed program.

• 한국컴퓨터그래픽스학회논문지
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• 제9권2호
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• pp.11-18
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• 2003

본 논문은 2차원 영상에서 커서를 특징 경계로 이동시키는 스내핑(snapping)과 특징 경계를 추출하는 래핑(wrapping)을 3차원 메쉬로 확장하여 메쉬상의 기하적 특징을 사용자가 의도한 대로 추출할 수 있는 기법을 다룬다. 먼저 메쉬상의 나타나는 기하적 특징을 계량화하기 위해 근사 곡률과 움직임 비용함수를 정의한다. 이들 수치 값을 기반으로 기하적 스내핑과 기하적 래핑 알고리즘을 설계한다. 본 논문에서는 제안한 알고리즘을 얼굴 메쉬와 치아 메쉬상에 나타나는 기하적 특징을 추출하기 위해 적용하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제25권4호
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• pp.196-220
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• 2021

This study formulates a new geometric parameterization scheme to effectively address numerical analysis subject to the variation of the fiber radius of a square unit cell. In particular, the proposed mesh-morphing approach may lead to a parameterized weak form whose bilinear and linear forms are affine in the geometric parameter of interest, i.e. the fiber radius. As a result, we may certify the reduced basis analysis of a square unit cell model for any parameters in a predetermined parameter domain with a rigorous a posteriori error bound. To demonstrate the utility of the proposed geometric parameterization, we consider a two-dimensional, steady-state heat conduction analysis dependent on two parameters: a fiber radius and a thermal conductivity. For rapid yet rigorous a posteriori error evaluation, we estimate a lower bound of a coercivity constant via the min-θ method as well as the successive constraint method. Compared to the corresponding finite element analysis, the constructed reduced basis analysis may yield nearly the same solution at a computational speed about 29 times faster on average. In conclusion, the proposed geometric parameterization scheme is conducive for accurate yet efficient reduced basis analysis.

• 대한기계학회논문집A
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• 제29권3호
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• pp.447-454
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• 2005

This paper presents a new paradigm for 3-axis tool path generation based on an incomplete 2-manifold mesh model, namely, an inexact polyhedron. When geometric data is transferred from one system to another system and tessellated for tool path generation, the model does not have any topological data between meshes and facets. In contrast to the existing polyhedral machining approach, the proposed method generates tool paths from an incomplete 2-manifold mesh model. In order to generate gouge-free tool paths, CL-meshes are generated by offsetting boundary edges, boundary vertices, and facets. The CL-meshes are sliced by machining planes and the calculated intersections are sorted, trimmed, and linked. The grid method is used to reduce the computing time when range searching problems arise. The method is fully implemented and verified by machining an incomplete 2-manifold mesh model.

• 전자공학회논문지CI
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• 제41권5호
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• pp.51-58
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• 2004

본 논문에서는 3D 모델의 체적 보존을 고려하는 메쉬 간략화 알고리듬을 제안하였다. 일반적으로 다른 대부분의 메쉬 간략화 알고리듬에서는 거리 기준을 사용한다. 거리는 기하학적인 오차를 측정하는 매우 효율적인 기준이기는 하지만 거리 기준만을 적용할 경우 원래 모델과 간략화된 모델 간에 체적 변화가 발생한다. 본 논문에서는 원래 모델의 간략화 과정 중에도 체적의 변화가 없는 메쉬 간략화 알고리듬을 제안한다. 본 알고리듬에서는 에지 하나를 줄이면서 체적의 변화가 일어나지 않는 정점 하나를 찾는 방식을 사용한다. 시뮬레이션을 통하여 제안하는 알고리듬이 비록 계산 시간은 좀 더 걸리지만 체적의 변화가 거의 없다는 장점을 가진 것을 확인하였다.