• Title/Summary/Keyword: Boundary Element Analysis

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Infinite Element for the Scaled Boundary Analysis of Initial Valued on-Homogeneous Elastic Half Space (초기값을 갖는 비동질무한영역의 해석을 위한 비례경계무한요소법)

  • Lee, Gye-Hee;Deeks, Andrew J.
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.21 no.2
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    • pp.199-208
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    • 2008
  • In this paper, to analyze the initial valued non-homogeneous elastic half space by the scaled boundary analysis, the infinite element approach was introduced. The free surface of the initial valued non-homogeneous elastic half space was modeled as a circumferential direction of boundary scaled boundary coordinate. The infinite element was used to represent the infinite length of the free surface. The initial value of material property(elastic modulus) was considered by the combination of the position of the scaling center and the power function of the radial direction. By use of the mapping type infinite element, the consistent elements formulation could be available. The performance and the feasibility of proposed approach are examined by two numerical examples.

Direct frequency domain analysis of concrete arch dams based on FE-(FE-HE)-BE technique

  • Lotfi, Vahid
    • Computers and Concrete
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    • v.1 no.3
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    • pp.285-302
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    • 2004
  • A FE-(FE-HE)-BE procedure is presented for dynamic analysis of concrete arch dams. In this technique, dam body is discretized by solid finite elements, while the reservoir domain is considered by a combination of fluid finite elements and a three-dimensional fluid hyper-element. Furthermore, foundation rock domain is handled by three-dimensional boundary element formulation. Based on this method, a previously developed program is modified, and the response of Morrow Point arch dam is studied for various conditions. Moreover, the effects of canyon shape on response of dam, is also discussed.

Analysis of Torque on Spur Gear by Inverse Problem (역문제에 의한 평치차의 토크 해석)

  • 박성완
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.5
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    • pp.24-33
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    • 2003
  • This study proposed a technique for inverse problem, linear approximation of contact position and loading in single and double meshing of transmission contact element using 2-dimension model considered near the tooth by root stress. Determination of root stress is carried out far the gear tooth by finite element method and boundary element method. Boundary element discretization near contact point is carefully performed to keep high computational accuracy. The predicted results of boundary element method are good accordance with that of finite element method.

Analysis of the Stresses for Hydraulic Actuator Cylinders using Boundary Element Method (경계요소법을 이용한 유압 엑츄에이터 실린더의 응력해석)

  • Kim, O.S.
    • Journal of Power System Engineering
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    • v.5 no.1
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    • pp.104-109
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    • 2001
  • The stress distributions of hydranlic actuator cylinder tube acting in uniform inner pressure were analysed by the boundary element method(BEM). STKM13C tube was utilized for machine structural purposes model, its inner radius was 100 mm and outer radius was 140 mm. Axial length was semi-infinite and the isoparametric element of BEM was used. Radial and tangential stresses are maximum(-20.3 MPa and 52 MPa) at the inner radius and the minimum at the outer radius of the hydraulic actuator cylinders for an industrial systems. Stress diminution ratio was about 0.6 MPa/mm. And then coincidence between the simulation techniques as exact results(Lame' equation) and finite element method(FEM) is found to be fairly good, showing that the proposed analysis by BEM is reliable.

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Detection of Cavities by Inverse Heat Conduction Boundary Element Method Using Minimal Energy Technique (최소 에너지기법을 이용한 역 열전도 경계요소법의 공동 탐지)

  • Choi, C.Y.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.17 no.4
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    • pp.237-247
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    • 1997
  • A geometrical inverse heat conduction problem is solved for the infrared scanning cavity detection by the boundary element method using minimal energy technique. By minimizing the kinetic energy of temperature field, boundary element equations are converted to the quadratic programming problem. A hypothetical inner boundary is defined such that the actual cavity is located interior to the domain. Temperatures at hypothetical inner boundary are determined to meet the constraints of mea- surement error of surface temperature obtained by infrared scanning, and then boundary element analysis is peformed for the position of an unknown boundary (cavity). Cavity detection algorithm is provided, and the effects of minimal energy technique on the inverse solution method are investigated by means of numerical analysis.

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Two-dimensional Stress Analysis Using Boundary Element Method (경계요소법(境界要素法)에 의한 2차원(次元) 응력해석(應力解析))

  • Chang-Doo,Jang;Sung-Hoon,Lee
    • Bulletin of the Society of Naval Architects of Korea
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    • v.23 no.4
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    • pp.11-18
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    • 1986
  • The fundamental theory and application of boundary element method for two-dimensional problem are introduced in this paper. Based on this boundary element procedure, several numerical calculations such as circular cavity problem, a thin plate with hole under tension and a long thick-walled cylinder under internal pressure are performed. The numerical results show fairly good agreement with exact solutions or results of finite element method.

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An effective finite element approach for soil-structure analysis in the time-domain

  • Lehmann, L.
    • Structural Engineering and Mechanics
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    • v.21 no.4
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    • pp.437-450
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    • 2005
  • In this study, a complete analysis of soil-structure interaction problems is presented which includes a modelling of the near surrounding of the building (near-field) and a special description of the wave propagation process in larger distances (far-field). In order to reduce the computational effort which can be very high for time domain analysis of wave propagation problems, a special approach based on similarity transformation of the infinite domain on the near-field/far-field interface is applied for the wave radiation of the far-field. The near-field is discretised with standard Finite Elements, which also allows to introduce non-linear material behaviour. In this paper, a new approach to calculate the involved convolution integrals is presented. This approximation in time leads to a dramatically reduced computational effort for long simulation times, while the accuracy of the method is not affected. Finally, some benchmark examples are presented, which are compared to a coupled Finite Element/Boundary Element approach. The results are in excellent agreement with those of the coupled Finite Element/Boundary Element procedure, while the accuracy is not reduced. Furthermore, the presented approach is easy to incorporate in any Finite Element code, so the practical relevance is high.

Automatic Quadrilateral Element Mesh Generation Using Boundary Normal Offsetting In Various Two Dimensional Objects (다양한 2차원 형상에서의 외부 경계 절점 오프셋 방법을 이용한 자동 사각 요소 및 요소망 생성)

  • 김도헌;양현익
    • Korean Journal of Computational Design and Engineering
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    • v.8 no.4
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    • pp.270-277
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    • 2003
  • In two dimensional mechanical design analysis, quadrilateral element mesh is preferred because it provides more accurate result than triangular element mesh. However, automation of quadrilateral element mesh generation is much more complex because of its geometrical complexities. In this study, an automatic quadrilateral element mesh generation algorithm based on the boundary normal offsetting method and the boundary decomposition method is developed. In so doing, nodes are automatically placed using the boundary normal offsetting method and the decomposition method is applied to decompose the designed domain into a set of convex subdomains. The generated elements are improved by relocation of the existing nodes based on the four criteria - uniformity, aspect ratio, skewness and taper degree. The developed algorithm requires minimal user inputs such as boundary data and the distance between nodes.

Development of Sound Radiation Analysis System Using the Results of Power Flow Finite Element Method (파워흐름유한요소법의 진동해석 결과를 이용한 구조물의 방사소음 해석시스템 개발)

  • 이호원;홍석윤
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.7
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    • pp.21-30
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    • 2001
  • The analysis system implementing a serial process from structural vibration to sound radiation has been developed using both the power flow finite element method (PFFEM) known as a new vibrational analysis technique in medium to high frequency ranges and the acoustic boundary element method (BEM) which is effective in analyzing the sound radiation problems. The vibration analysis for arbitrary shape structures composed of plates is performed, and using the vibration energy density obtained from this analysis as the velocity boundary conditions for an acoustic analysis, vibro-acoustic analysis has been processed. To verify the developed system, we select a simple structure model and compare the results of developed system with those of SYSNOISE, and also the developed system is applied for the vibro-acoustic analysis of various structures in shapes.

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Mesh Design for the Finite Element Analysis of Thin Structures with Boundary Layers (경계층을 가진 박판구조물의 유한요소 해석을 위한 체눈 디자인)

  • 조진래
    • Computational Structural Engineering
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    • v.9 no.4
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    • pp.165-172
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    • 1996
  • For thin elastic structures such as beams, arches, plates and shells, there may exist the boundary layer in the narrow thin region neighborhood of boundaries, where the solution displays the singular behavior exponentially decaying in the normal direction to the boundary. In the finite element analysis of these structures, finite element mesh patterns have a significant role to capture this singularity. This paper introduces the analytic study of this problem and provides a guideline to construct optimal mesh patterns together with numerical experiments.

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