• Title/Summary/Keyword: mesh generation

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Techniques of Automatic Finite Element Mesh Generation on Surface Primitives (원시곡면 위의 유한요소망 자동생성 기법)

  • 이재영
    • Korean Journal of Computational Design and Engineering
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    • v.1 no.3
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    • pp.189-202
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    • 1996
  • Complex geometric shapes can be defined simply and efficiently by combining and operating various surface primitives. These primitives and their intersection curves are used in finite element mesh generation to form an easy and intuitive procedure for finite element modelling of curved surfaces. This paper proposes techniques of automatic mesh generation on surface primitives with arbitrarily shaped boundaries and control curves, which may be created by surface to surface intersection. A method of automatic mesh generation on plane, which was previously developed by the author, has been modified for application to the surface mesh generation. Owing to the mesh generation-wise differences between planes and surfaces, the surfaces should be transformed into conceptual plane so that the modified plane mesh generation method can be applied. Surface development, mapping and mesh reconstruction are the key techniques suggested in this paper. The selection of the technique to apply can be determined automatically on the basis of the developability, existence of singularity and other characteristics of the surfaces on which the mesh is to be generated. The suggested techniques were implemented into parts of mesh generation functions of the finite element software, MacTran. Their validity and practicality were manifested by the actual use of this software.

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Automatic Triangular Mesh Generation Over B-Spline Surfaces Including Arbitrary Holes (임의의 구멍을 포함하는 B-Spline 곡면상에서의 자동 삼각 요소망 생성)

  • 김근호;양현익
    • Korean Journal of Computational Design and Engineering
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    • v.9 no.1
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    • pp.1-10
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    • 2004
  • In the process of finite element analysis, mesh generation is tedious job which consumes tremendous time. Therefore, the automation of well shaped mesh generation from the minimal boundary input data is desirable to improve reliability and accuracy of the analysis and also to reduce the process time of the entire design process. The automation of triangular mesh generation has been relatively well treated due to its robustness and ease of handling when compared to rectangular element mesh generation. In this study, the offset method developed previously for generating plane rectangular element mesh has been corrected and modified to generate triangular element mesh on the B-spline surface having arbitrary holes. The result shows that the generated triangular mesh has the average aspect ratio over 0.9. The designed arbitrary surface shape has been interactively constructed by non-uniform B-spline theory for triangular mesh generation.

Automated Mesh Generation For Finite Element Analysis In Metal Forming (소성 가공의 유한 요소 해석을 위한 자동 요소망 생성)

  • 이상훈;오수익
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.10a
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    • pp.17-23
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    • 1997
  • In the two-dimensional Finite Element Method for forming simulation, mesh generation and remeshing process are very significant. In this paper, using the modified splitting mesh generation algorithm, we can overcome the limitation of existing techniques and acquire mesh, which has optimal mesh density. A modified splitting algorithm for automatically generating quadrilateral mesh within a complex domain is described. Unnecessary meshing process for density representation is removed. Especially, during the mesh generation with high gradient density like as shear band representation, the modified mesh density scheme, which will generate quadrilateral mesh with the minimized error, which takes effect on FEM solver, is introduced.

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AUTOMATED QUADRILATERAL SURFACE MESH GENERATION ON THREE-DIMENSIONAL SURFACES (3차원 물체 표면상의 비정렬 사변형 격자의 자동 생성 기법)

  • Won, J.H.;Kim, B.S.
    • 한국전산유체공학회:학술대회논문집
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    • 2006.10a
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    • pp.70-73
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    • 2006
  • Mesh generation for the region of interest is prerequisite for numerical analysis of governing partial differential equations describing phenomena with proper physic. Mesh generation is, however, usually considered as a major obstacle for a routine application of numerical approaches in Engineering applications. Therefore automatic mesh generation is highly pursued. In this paper automated quadrilateral surface mesh generation is proposed. According to the present method, Cartesian cells of proper resolution for a region bounding the whole region of interest are first generated and the interior cells are identified. Then projecting their surface meshes onto the boundary surfaces gives surface mesh consisting of quadrilateral cells. This method has been implemented as an application program, and example cases are given.

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The Development of the Automatic Triangular Mesh Generation Software Using Modified Lo's Algorithm (수정된 Lo의 요소망 생성 알고리즘은 이용한 자동 삼각 요소망 생성 소프트웨어의 개발)

  • 김병옥;양현익
    • Korean Journal of Computational Design and Engineering
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    • v.5 no.1
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    • pp.95-101
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    • 2000
  • For last two decades numerous automatic mesh generation algorithms for various two dimensional objects have been introduced continuously and among them triangular mesh generation schemes have been majority because of efficiency and controllability. In our study, an existing triangular mesh generation algorithm developed by Lo is totally modified to more improve node distribution, element shape, and objects shape independency. ft is composed of node generation part and element generation part. In order to find a suitable node position within geometry, the suggested algorithm searches desirable positions of points within boundary and optimizes node position to generate comparatively well-shaped elements. More over, the suggested algorithm handles various complex two dimensional objects and its meshing speed shows superiority to those of the existing triangulation mesh generation algorithms. It is fully automated in a sense of constructing object boundary and hence can be directly used as an independent meshing software.

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Two Dimensional Automatic Quadrilateral Mesh Generation for Metal Forming Analysis (소성 가공 공정 해석을 위한 2차원 사각 요소망 자동 생성)

  • Kim, Sang-Eun;Yang, Hyun-Ik
    • Korean Journal of Computational Design and Engineering
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    • v.14 no.3
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    • pp.197-206
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    • 2009
  • In a finite element analysis of the metal forming processes having large plastic deformation, largely distorted elements are unstable and hence they influence upon the result toward negative way so that adaptive remeshing is required to avoid a failure in the numerical computation. Therefore automatic mesh generation and regeneration is very important to avoid a numerical failure in a finite element analysis. In case of generating quadrilateral mesh, the automation is more difficult than that of triangular mesh because of its geometric complexity. However its demand is very high due to the precision of analysis. Thus, in this study, an automatic quadrilateral mesh generation and regeneration method using grid-based approach is developed. The developed method contains decision of grid size to generate initial mesh inside a two dimensional domain, classification of boundary angles and inner boundary nodes to improve element qualities in case of concave domains, and boundary projection to construct the final mesh.

Delaunay mesh generation technique adaptive to the mesh Density using the optimization technique (최적화 방법을 이용한 Delaunay 격자의 내부 격자밀도 적응 방법)

  • Hong J. T.;Lee S. R.;Park C. H.;Yang D. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.10a
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    • pp.75-78
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    • 2004
  • A mesh generation algorithm adapted to the mesh density map using the Delaunay mesh generation technique is developed. In the finite element analyses of the forging processes, the numerical error increases as the process goes on because of discrete property of the finite elements or severe distortion of elements. Especially, in the region where stresses and strains are concentrated, the numerical discretization error will be highly increased. However, it is too time consuming to use a uniformly fine mesh in the whole domain to reduce the expected numerical error. Therefore, it is necessary to construct locally refined mesh at the region where the error is concentrated such as at the die corner. In this study, the point insertion algorithm is used and the mesh size is controlled by moving nodes to optimized positions according to a mesh density map constructed with a posteriori error estimation. An optimization technique is adopted to obtain a good position of nodes. And optimized smoothing techniques are also adopted to have smooth distribution of the mesh and improve the mesh element quality.

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Automatic Mesh Generation for Three-Dimensional Structures Consisting of Free-Form Surfaces (자유 곡면으로 구성되는 3차원 구조물에 대한 자동 요소 분할)

  • ;Yagawa, Genki
    • Korean Journal of Computational Design and Engineering
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    • v.1 no.1
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    • pp.65-75
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    • 1996
  • This paper describes an automatic finite element(FE) mesh generation for three-dimensional structures consisting of free-form surfaces. This mesh generation process consists of three subprocesses: (a) definition of geometric model, i.e. analysis model, (b) generation of nodes, and (c) generation of elements. One of commercial solid modelers is employed for three-dimensional solid and shell structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Delaunay method is introduced as a basic tool for element generation. Automatic generation of FE meshes for three-dimensional solid and shell structures holds great benefits for analyses. Practical performances of the present system are demonstrated through several mesh generations for three-dimensional complex geometry.

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A mesh generation based on the pollution error (Pollution 오차를 이용한 요소생성에 관한 연구)

  • 유형선;편수범
    • Journal of the Korean Society for Railway
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    • v.2 no.3
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    • pp.46-53
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    • 1999
  • In this paper, made was a study on a mesh generation method based on the pollution error. This method is designed for the control of the pollution error in any patch of elements of interest. It is a well-known fact that the pollution error estimates are much more than the local one. When the pollution error is significant, nothing can be said about the reliability of any estimator based on local computations in the patch. Reliable a posteriori error estimation is possible by controlling the pollution error in the patch through proper design of the mesh outside the patch. This design is possible by equally distributing the pollution error indicators over the mesh outside the patch. The mesh generated from the conventional feedback pollution-adaptive mesh generation algorithm needs many iterations. Therefore, the solution time is significant. But the remeshing scheme in the proposed method was used here. It was shown that the pollution-adaptive mesh improves the E.I., simply denoted as Effectivity Index, on the patch of interest, and the pollution error reduces less than the local error.

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Tetrahedral Mesh Generation by Using the Advancing-Front Method and the Optimal Surface Triangular Mesh Generation Technique (전진경계기법과 최적 표면 삼각형 요소망 생성 기법을 이용한 사면체 요소망의 생성)

  • Lee M.C.;Joun M.S.
    • Korean Journal of Computational Design and Engineering
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    • v.11 no.2
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    • pp.138-147
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    • 2006
  • A systematic approach to tetrahedral element or mesh generation, based on an advancing-front method and an optimal triangular mesh generation technique on the surface, is presented in this paper. The possible internal nodes are obtained by the octree-decomposition scheme. The initial tetrahedral mesh system is constructed by the advancing-front method and then it is improved by the quality improvement processes including mesh swapping and nodal smoothing. The approach is evaluated by investigating the normalized length, the normalized volume, the dihedral angle and the normalized quality