• Title/Summary/Keyword: mesh regeneration

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Novel Mesh Regeneration Method Using the Structural Deformation Analysis for 3D Shape Optimization of Electromagnetic Device (전자소자의 3차원 형상최적화를 위한 구조변형 해석을 이용한 새로운 요소망 변형법)

  • Yao Yingying;Jae Seop Ryu;Chang Seop Koh;Dexin Xie
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.52 no.6
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    • pp.247-253
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    • 2003
  • A novel finite element mesh regeneration method is presented for 3D shape optimization of electromagnetic devices. The method has its theoretical basis in the structural deformation of an elastic body. When the shape of the electromagnetic devices changes during the optimization process, a proper 3D finite element mesh can be easily obtained using the method from the initial mesh. For real engineering problems, the method guarantees a smooth shape with proper mesh quality, and maintains the same mesh topology as the initial mesh. Application of the optimum design of an electromagnetic shielding plate shows the effectiveness of the presented method.

A New 3D Mesh Regeneration Method in the Shape Optimal Design of (전자소자의 형상최적화를 위한 3차원 요소의 재생성법)

  • Yao, Yingying;Koh, Chang-Seop;Xie, Dexin
    • Proceedings of the KIEE Conference
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    • pp.841-843
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    • 2002
  • A novel and simple method, which can be used to automatically regenerate 3D finite element meshes, is presented in the paper. This technique based on the structural deformation analysis. It is problem independent and can be used to renew the mesh of any kind of 3D shape design system whether the geometric surface is parameterized or not. The mesh deformation degree can be adjusted by choosing suitable subregion and giving proper parameters. It is sufficient to obtain a smooth contour with proper mesh quality. Application to the optimum design of shielding plate shows the effectiveness of the proposed technique.

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A Study on The Prediction of Workpiece Shape of The Electrochemical Machining by Boundary Element Method (경계요소법에 의한 전해가공물의 형상예측에 관한 연구)

  • 강대철;양재봉;김헌영;전병희
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.443-447
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    • 2003
  • The BEM (Boundary Element Method) is a computational technique for the approximate solution of problems in continuum mechanics. In the BEM both volume and surface integrals transformed into boundary integral equations. So, we applied the ECM (Electrochemical Machining) process to boundary problem, because our focus is only deformed shape. The ECM process is modeled as a two-dimensional problem assuming constant properties of electrolyte, and an incremental formulation is used with automatic mesh regeneration. As a result the final shape is roughly agreed with experimental shape. But, it has an error of exact shape, because a chemically factor is not considered

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Structural Dynamics Modification using Reduced Model for Having Non-matching Nodes (불일치 절점을 가지는 경우의 축약된 모델을 이용한 동특성 변경법)

  • Kang, Ok-Hyun;Park, Youn-Sik;Park, Young-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.830-833
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    • 2005
  • SDM(Structural Dynamics Modification) is to improve dynamic characteristics of a structure, more specifically of a base structure, by adding or deleting auxiliary(modifying) structures. In this paper, I will focus on the optimal layout of the stiffeners which are attached to the plate to maximize 1st natural frequency. Recently, a new topology method was proposed by yamazaki. He uses growing and branching tree model. I modified the growing and branching tree model. The method is designated modified tree model. To expand the layout of stiffeners, I will consider non-matching problem. The problem is solved by using local lagrange multiplier without the mesh regeneration. Moreover The CMS(Component mode synthesis) method is employed to reduce the computing time of eigen reanalysis using reduced componet models.

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DEVELOPMENT OF SPECIALIZED GRID GENERATION PROGRAM FOR MULTI-ELEMENT AIRFOIL AERODYNAMIC ANALYSIS (다중익형 공력 계산을 위한 특화 격자생성 프로그램 개발)

  • Nam, D.W.;Lee, Y.J.;Lee, J.Y.;Kim, B.S.
    • Journal of computational fluids engineering
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    • v.21 no.4
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    • pp.85-89
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    • 2016
  • Wing is the most important part of aircraft which produces lift. In general when aircraft takes off or lands, high lift is required and additional devices are adopted in front and aft-side of wing, which constitute so-called multi element airfoils. The objective of this research is to develop a specialized grid generation program to help engineers in reducing human labor and eliminating time-consuming process for mesh regeneration by deforming the initially-given grid system with efficient deforming method. This paper describes briefly about the mesh deformation methods, and provides some results to verify the quality of deformed mesh and eventually correctness of current approach.

3D Optimal Design of Transformer Tank Shields using Design Sensitivity Analysis

  • Yingying Yao;Ryu, Jae-Seop;Koh, Chang-Seop;Dexin Xie
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.3B no.1
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    • pp.23-31
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    • 2003
  • A novel 3D shape optimization algorithm is presented for electromagnetic devices carry-ing eddy current. The algorithm integrates the 3D finite element performance analysis and the steepest descent method with design sensitivity and mesh relocation method. For the design sensitivity formula, the adjoint variable vector is defined in complex form based on the 3D finite element method for eddy current problems. A new 3D mesh relocation method is also proposed using the deformation theory of the elastic body under stress to renew the mesh as the shape changes. The design sensitivity f3r the sur-face nodal points is also systematically converted into that for the design variables for the parameterized optimization application. The proposed algorithm is applied to the optimum design of the tank shield model of the transformer and the effectiveness is proved.

The 3D Shape Optimal Design of Transformer Tank Shield by Using Parameterized Design Sensitivity Analysis

  • Yao, Ying-Ying;Ryu, Jae-Seop;Koh, Chang-Seop;Xie, Dexin
    • Proceedings of the KIEE Conference
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    • pp.80-83
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    • 2002
  • A 3D shape optimization algorithm integrates the geometric parameterizationi 3D F.E. performance analysis, steepest descent method with design sensitivity and mesh relocation method. The design sensitivity of the surface nodal points is also systematically converted into that of the design variables for the application to parameterized optimization. The proposed algorithm is applied to the optimum design of tank shield model of transformer and the effectiveness is proved.

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An Electrical Conductivity Reconstruction for Evaluating Bone Mineral Density : Simulation (골 밀도 평가를 위한 뼈의 전기 전도도 재구성: 시뮬레이션)

  • 최민주;김민찬;강관석;최흥호
    • Journal of Biomedical Engineering Research
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    • v.25 no.4
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    • pp.261-268
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    • 2004
  • Osteoporosis is a clinical condition in which the amount of bone tissue is reduced and the likelihood of fracture is increased. It is known that the electrical property of the bone is related to its density, and, in particular, the electrical resistance of the bone decreases as the bone loss increases. This implies that the electrical property of bone may be an useful parameter to diagnose osteoporosis, provided that it can be readily measured. The study attempted to evaluate the electrical conductivity of bone using a technique of electrical impedance tomography (EIT). It nay not be easy in general to get an EIT for the bone due to the big difference (an order of 2) of electrical properties between the bone and the surrounding soft tissue. In the present study, we took an adaptive mesh regeneration technique originally developed for the detection of two phase boundaries and modified it to be able to reconstruct the electrical conductivity inside the boundary provided that the geometry of the boundary was given. Numerical simulation was carried out for a tibia phantom, circular cylindrical phantom (radius of 40 mm) inside of which there is an ellipsoidal homeogenous tibia bone (short and long radius are 17 mm and 15 mm, respectively) surrounded by the soft tissue. The bone was located in the 15 mm above from the center of the circular cross section of the phantom. The electrical conductivity of the soft tissue was set to be 4 mS/cm and varies from 0.01 to 1 ms/cm for the bone. The simulation considered measurement errors in order to look into its effects. The simulated results showed that, if the measurement error was maintained less than 5 %, the reconstructed electrical conductivity of the bone was within 10 % errors. The accuracy increased with the electrical conductivity of the bone, as expected. This indicates that the present technique provides more accurate information for osteoporotic bones. It should be noted that tile simulation is based on a simple two phase image for the bone and the surrounding soft tissue when its anatomical information is provided. Nevertheless, the study indicates the possibility that the EIT technique may be used as a new means to detect the bone loss leading to osteoporotic fractures.