• 한국생산제조학회지
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• 제6권4호
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• pp.65-71
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• 1997

The automation of mesh generation in BEM is very important in numerical analysis field for the time and efficiency. In order to this problem, program and algorithm to achive the purpose of making input data and automation of mesh generation based in Expert System are developed in this study. This program has the function of rotating and zooming. The stress intensity factor which is a criteria of fracture mechanics is calculated and compared with other results to prove efficiency and availability of the program in result.

• Journal of Computational Design and Engineering
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• 제2권4호
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• pp.268-275
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• 2015

Blisk is an essential component in aero engines. To maintain good aero-dynamic performance, one critical machining requirement for blades on blisk is that the generated five-axis tool path should be boundary-conformed. For a blade discretely modeled as a point cloud or mesh, most existing popular tool path generation methods are unable to meet this requirement. To address this issue, a novel five-axis tool path generation method for a discretized blade on blisk is presented in this paper. An idea called Linear Morphing Cone (LMC) is first proposed, which sets the boundary of the blade as the constraint. Based on this LMC, a CC curve generation and expansion method is then proposed with the specified machining accuracy upheld. Using the proposed tool path generation method, experiments on discretized blades are carried out, whose results show that the generated tool paths are both uniform and boundary-conformed.

• 한국정밀공학회지
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• 제17권3호
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• pp.136-148
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• 2000

In this work, a general method for the mathematical description of three-dimensional trimmed surface is proposed by introducing the base parametric surface and boundary curves. Since mesh density distribution for the analysis may vary by cases, a grid-based mesh generation algorithm using quadtree is proposed in the present work. For the assurance of connectivity of generated meshes among surfaces, a method for the pre-cleaning of boundary curves has been developed to be used in the automatic generation of the finite elements. In addition, mesh-smoothing algorithm is suggested which can be used in the general trimmed surface. In this algorithm nodes are moved on the original surface by the normal projection in each iterative smoothing procedure.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1992년도 봄 학술발표회 논문집
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• pp.39-44
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• 1992

This paper proposes a method of h-type adaptive mesh generation for the finite element analysis of two dimensional elasticity problem. The error energy norm of a posteriori error estimation is difined based on the complementary energy of each element. Computer codes are developed and some examples are investigated. It is shown that the approach to the optimized mesh in this paper is effective and useful.

• 해양환경안전학회지
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• 제23권7호
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• pp.791-800
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• 2017

선박 거주구역에 화재발생 시 화재시뮬레이션 도구를 이용하여 화재확산형상을 실시간으로 예측하고 상황에 따른 적절한 대응방안을 제시할 수 있다면 화재사고로 인한 인명피해를 최소화시킬 수 있을 것으로 예상된다. 그러나 오늘날 화재시뮬레이션은 해석대상공간의 크기와 그리드 개수에 따라 해석을 하는데 있어, 매우 장시간을 필요로 하는 현실적 한계가 있다. 이에 이 연구에서는 화재시뮬레이션 시간단축을 목적으로 선박 거주구역 화재시뮬레이션에 적용할 수 있는 격자크기와 생성방법에 대한 연구를 수행하였다. 연구결과 선박 거주구역에 적용되는 격자크기는 0.25[m] 이내의 값을 사용하는 것이 가장 효율적인 것으로 판단되었다. 또한 single mesh 격자생성방법으로 수행했을 경우와 비교하여, multi mesh 격자생성방법으로 시뮬레이션을 수행하였을 때 가시거리 값은 4.3 %, 온도 값은 8.3 % 이내에서 유사하고 해석시간은 약 80 % 감소하였기 때문에, multi mesh 방법으로 격자를 생성하는 것이 해석시간을 단축하는데 있어 매우 효과적임을 확인하였다.

• 대한기계학회논문집A
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• 제25권12호
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• pp.1926-1932
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• 2001

In this second part of the paper, the automatic mesh generation and remeshing algorithm using bubble packing method is applied to the nonlinear problem. The remeshing/refinement procedure is necessary in the large deformation process especially because the mesh distortion deteriorates the convergence and accuracy. To perform the nonliear analysis, the transfer of state variables such as displacement and strain is added to the algorithm of Part 1. The equilibrium equation based on total Lagrangian formulation and elasto-viscoplastic model is used. For the numerical experiment, the upsetting process including the contact constraint condition is analyzed by two refinement criteria. And from the result, it is addressed that the present algorithm can generate the refined meshes easily at the largely deformed area with high error.

• 한국전산구조공학회논문집
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• 제23권6호
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• pp.659-665
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• 2010

The finite element method(FEM) is proven to be an effective approximate method of structural analysis if proper element types and meshes are chosen, and recently, the method is often applied to solve complex dynamic and nonlinear problems. A properly chosen element type and mesh yields reliable results for dynamic finite element structural analysis. However, dynamic behavior of a structure may include unpredictably large strains in some parts of the structure, and using the initial mesh throughout the duration of a dynamic analysis may include some elements to go through strains beyond the elements' reliable limits. Thus, the finite element mesh for a dynamic analysis must be dynamically adaptive, and considering the rapid process of analysis in real time, the dynamically adaptive finite element mesh generating schemes must be computationally efficient. In this paper, a computationally efficient dynamically adaptive finite element mesh generation scheme for dynamic analyses of structures is described. The concept of representative strain value is used for error estimates and the refinements of meshes use combinations of the h-method(node movement) and the r-method(element division). The shape coefficient for element mesh is used to correct overly distorted elements. The validity of the scheme is shown through a cantilever beam example under a concentrated load with varying values. The example shows reasonable accuracy and efficient computing time. Furthermore, the study shows the potential for the scheme's effective use in complex structural dynamic problems such as those under seismic or erratic wind loads.

• 한국산학기술학회논문지
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• 제10권9호
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• pp.2183-2188
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• 2009

본 논문은 3차원 균열의 유한요소해석을 위한 자동요소분할시스템에 대한 것으로, 논문의 구성은 퍼지지식처리, 버블메슁, 솔리드모델러로 구성된다. 새로운 요소분할과정은 (a) 해석모델인 기하학적 모델 정의, (b) 버블생성, (c), 요소분할로 구성되어 진다. 3차원 균열체를 위해 범용솔리드 모델러를 사용하였으며 버블은 존재하는 버블점들간의 거리가 그 점에서의 버블간격 함수와 유사한지를 결정하여 발생되어 진다. 버블간격 함수는 퍼지지식처리에 의해 잘 조절되어 진다. 요소생성에 관한 기본 툴로서는 데로우니기법이 사용되었다. 시스템의 실제적인 효용성을 검증하기 위해 3차원 균열에 대한 몇가지 예를 나타내었다.

• Structural Engineering and Mechanics
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• 제45권3호
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• pp.411-422
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• 2013

A well-designed mesh shape of the cable net is of essential significance to achieve high performance of cable-network antenna reflectors. This paper is concerned with the mesh design problem for such antenna reflector structure. Two new methods for creating the topological forms of the cable net are first presented. Among those, the cyclosymmetry method is useful to generate different polygon-faceted meshes, while the topological mapping method is suitable for acquiring triangle-faceted meshes with different mesh grid densities. Then, the desired spatial paraboloidal mesh geometrical configuration in the state of static equilibrium is formed by applying a simple mesh generation approach based on the force density method. The main contribution of this study is that a general technical guide for how to create the connectivities between the nodes and members in the cable net is provided from the topological point of view. With the new idea presented in this paper, multitudes of mesh configurations with different net patterns can be sought by a certain rule rather than by empiricism, which consequently gives a valuable technical reference for the mesh design of this type of cable-network structures in the engineering.

• International Journal of CAD/CAM
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• 제11권1호
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• pp.11-17
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• 2011

A new method has been developed in this paper for automatic quadrilateral mesh generation for a two-dimensional domain. The method is named 'centering method' because it centers a point at the domain and then divides it into sub-domains using cutting lines from the center point. Each of the cutting lines is selected based on the criterion using the angles between the boundary of the domain and the cutting line. The decomposition of the domain into sub-domains is repeated until every subdomain has four or six nodes. Pre-defined splitters are used to divide six-node domains into quadrilateral elements depending on their configuration and presence on the boundary of the initial domain. Arbitrary domains are meshed as examples to verify the robustness of the new method.