• Structural Engineering and Mechanics
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• 제69권5호
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• pp.527-536
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• 2019

This paper will compare $T3{\gamma}_s$ and MITC3 elements, both these two elements are three-node triangular plate bending elements with three degrees of freedom per node. The formulation of the $T3{\gamma}_s$ and MITC3 elements is rather simple and has already been widely used. This paper will prove that the shear strain formulation of these two elements is identical even though they are obtained from two different methods. A single element is used to test the formulation of shear strain matrices. Numerical tests for circular plate cases compared with the exact solutions and with DKMT element will complete this review to verify the performances and show the convergence of these two elements.

• 한국게임학회 논문지
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• 제2권1호
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• pp.62-68
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• 2002

본 연구에서는 기존의 곡면 삼각화 방법들이 많은 수의 삼각형 메쉬를 사용하면서도 정확하게 표현하기가 힘들었던, 날카로운 모서리를 가지는 곡면을 처리할 수 있는 trammed NURBS곡면 삼각화 방법을 제안, 구현하였다. 기존의 매개변수영역에서의 삼각화의 문제점인 3차원공간상의 삼각형 메쉬를 계산할 때의 왜곡현상을 해결하기 위해서 곡면의 펼친영역을 근사적으로 계산하여 삼각화 하는 방법을 사용했다. 곡선, 곡면의 날카로운 점과 모서리를 자동으로 인식하기 위해서 1차미분 연속조건을 이용하였고, 이를 제약조건으로 constraint Delaunay 삼각화방법을 사용하여 곡면의 날카로운 형상(sharp shape)을 유지하면서 삼각화를 수행할 수 있었다. 제안된 삼각화 방법은 기존의 삼각화 방법에 비하여 적은수의 삼각형 메쉬로 곡면의 날카로운 모서리를 보다 정확하게 표현 할 수 있는 장점을 가지고 있어서 삼각형의 개수에 따라 가시화 성능이 큰 영향을 받는 컴퓨터게임 같은 분야에 도움을 줄 수 있으리라 예상된다.

• 한국통신학회논문지
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• 제22권6호
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• pp.1244-1250
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• 1997

An arbitrary shaped iris in rectangular waveguideis investigated using FEM-CDMA with triangularprism elements in this paper. The volume of irisis subdivided into a relatively small number of triangular prism elements and FEM is used to formulate the field distribution. On the other hand, the fields in the waveguide region are represented by BIM derived from the waveguide Green's function and boundary conditions. The proposed method is verified through the design and experiment for the circular iris filter using WR-90 waveguide.

• Structural Engineering and Mechanics
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• 제76권3호
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• pp.379-393
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• 2020

In this paper, we propose an automatic procedure to improve the accuracy of finite element solutions using enriched 2D solid finite elements (4-node quadrilateral and 3-node triangular elements). The enriched elements can improve solution accuracy without mesh refinement by adding cover functions to the displacement interpolation of the standard elements. The enrichment scheme is more effective when used adaptively for areas with insufficient accuracy rather than the entire model. For given meshes, an error for each node is estimated, and then proper degrees of cover functions are applied to the selected nodes. A new error estimation method and cover function selection scheme are devised for the proposed adaptive enrichment scheme. Herein, we demonstrate the proposed enrichment scheme through several 2D problems.

• Structural Engineering and Mechanics
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• 제39권6호
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• pp.767-793
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• 2011

An efficient edge-based smoothed finite element method (ES-FEM) has been recently developed for solving solid mechanics problems. The ES-FEM uses triangular elements that can be generated easily for complicated domains. In this paper, the complexity study of the ES-FEM based on triangular elements is conducted in detail, which confirms the ES-FEM produces higher computational efficiency compared to the FEM. Therefore, the ES-FEM offers an excellent platform for adaptive analysis, and this paper presents an efficient adaptive procedure based on the ES-FEM. A smoothing domain based energy (SDE) error estimate is first devised making use of the features of the ES-FEM. The present error estimate differs from the conventional approaches and evaluates error based on smoothing domains used in the ES-FEM. A local refinement technique based on the Delaunay algorithm is then implemented to achieve high efficiency in the mesh refinement. In this refinement technique, each node is assigned a scaling factor to control the local nodal density, and refinement of the neighborhood of a node is accomplished simply by adjusting its scaling factor. Intensive numerical studies, including an actual engineering problem of an automobile part, show that the proposed adaptive procedure is effective and efficient in producing solutions of desired accuracy.

• Educational Technology International
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• 제21권1호
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• pp.31-67
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• 2020

The purpose of this study was to propose an education cooperation model for Human Resources Development (HRD) in Asia-Pacific region in response to environmental changes in business and industry. In order to carry out the model, this study reviewed the key features of human resources in the APEC which is a symbolic regional integration entity in Asia-Pacific region, shaped critical issues related with HRD in this region and then analyzed the trends of education cooperation projects conducted by the APEC in terms of topics, implementation methods and proposing economies of the projects. In result, this study proposed a triangular education cooperation model for HRD consisting of three elements: Voluntary Partnership, Information on Needs and Support for Cooperation. These interconnected and interdependent elements were designed to encourage actors to participate in education cooperative activities with their own willingness, produce and manage research-based information required for sustainable cooperation and support communication and connectivity among actors for effective activities. Also, this study expected that this model would make a commitment to narrowing educational divides, enhancing global-standard skills development, facilitating public and private partnership and organizing the foundation of future education for cultivating creative talents in the era of innovation for APEC members.

• Journal of applied mathematics & informatics
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• 제42권1호
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• pp.1-14
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• 2024

Let G = (V, E) be a (p, q) graph. Define $$\begin{cases}\frac{p}{2},\:if\:p\:is\:even\\\frac{p-1}{2},\:if\:p\:is\:odd\end{cases}$$ and L = {±1, ±2, ±3, ···, ±ρ} called the set of labels. Consider a mapping f : V → L by assigning different labels in L to the different elements of V when p is even and different labels in L to p - 1 elements of V and repeating a label for the remaining one vertex when p is odd.The labeling as defined above is said to be a pair difference cordial labeling if for each edge uv of G there exists a labeling |f(u) - f(v)| such that |Δ_f1 - Δ_f^c1| ≤ 1, where Δ_f1 and Δ_f^c1 respectively denote the number of edges labeled with 1 and number of edges not labeled with 1. A graph G for which there exists a pair difference cordial labeling is called a pair difference cordial graph. In this paper we investigate the pair difference cordial labeling behavior of subdivision of some graphs.

• Structural Engineering and Mechanics
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• 제68권4호
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• pp.385-398
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• 2018

In the present paper, we offer a new flat shell finite element. It is the result of the combination of a membrane element and a bending element, both based on the strain-based formulation. It is known that $C^{\circ}$ plane membrane elements provide poor deflection and stress for problems where bending is dominant. In addition, they encounter continuity and compliance problems when they connect to C1 class plate elements. The reach of the present work is to surmount these problems when a membrane element is coupled with a thin plate element in order to construct a shell element. The membrane element used is a triangular element with four nodes, three nodes at the vertices of the triangle and the fourth one at its barycenter. Each node has three degrees of freedom, two translations and one rotation around the normal. The coefficients related to the degrees of freedom at the internal node are subsequently removed from the element stiffness matrix by using the static condensation technique. The interpolation functions of strain, displacements and stresses fields are developed from equilibrium conditions. The plate element used for the construction of the present shell element is a triangular four-node thin plate element based on Kirchhoff plate theory, the strain approach, the four fictitious node, the static condensation and the analytic integration. The shell element result of this combination is robust, competitive and efficient.

• 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.

• 한국CDE학회논문집
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• 제10권1호
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• pp.70-75
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• 2005

A 3D solid element mesh generation algorithm was newly developed. 3D surface points of global rectangular coordinates were supplied by a 3D laser scanner. The algorithm is strait forward and simple but it generates mixed solid elements such as hexagonal, pyramid and prism types. Then, the surface triangular or rectangular elements were generated from the solid elements. The key of the algorithm is elimination of elements and 3D adaptive surface smoothing using given 3D surface point data.