• Title/Summary/Keyword: Boundary Integral Equation

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Electric Field Analysis Using Three Dimensional Boundary Integral Equation Method (3차원 경계적분방정식법을 이용한 정전장 해석)

  • Kim, Jae-Hong;Kim, Dong-Hun;Park, Il-Han
    • Proceedings of the KIEE Conference
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    • 2000.07b
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    • pp.828-830
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    • 2000
  • This paper describes BIEM(Boundary Integral Equation Method) for computation of three dimensional electric field distribution and numerical method that an equivalent charge density is unknown variable. After computing numerically the surface charge distribution. the distribution of both potential and electric field are obtained. Finally, this numerical method is applied to the concentric sphere and the coaxial cylindrical model and numerical result is compared to the analytic solution.

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Effects of Anisotropic Fiber Packing on Stresses in Composites (이방성 섬유의 배열이 복합재료의 응력에 미치는 영향)

  • Lee, Jung-Ki;Lee, Hyeong-Min
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.9
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    • pp.1284-1296
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    • 2004
  • In order to investigate effects of anisotropic fiber packing on stresses in composites, a Volume Integral Equation Method is applied to calculate the elastostatic field in an unbounded isotropic elastic medium containing multiple orthotropic inclusions subject to remote loading, and a Mixed Volume and Boundary Integral Equation Method is introduced for the solution of elastostatic problems in unbounded isotropic materials containing multiple anisotropic inclusions as well as one void under uniform remote loading. A detailed analysis of stress fields at the interface between the isotropic matrix and the central orthotropic inclusion is carried out for square, hexagonal and random packing of orthotropic cylindrical inclusions, respectively. Also, an analysis of stress fields at the interface between the isotropic matrix and the central orthotropic inclusion is carried out, when it is assumed that a void is replaced with one inclusion adjacent to the central inclusion of square, hexagonal and random packing of orthotropic cylindrical inclusions, respectively, due to manufacturing and/or service induced defects. The effects of random orthotropic fiber packing on stresses at the interface between the isotropic matrix and the central orthotropic inclusion are compared with the influences of square and hexagonal orthotropic fiber packing on stresses. Through the analysis of plane elastostatic problems in unbounded isotropic matrix with multiple orthotropic inclusions and one void, it will be established that these new methods are very accurate and effective for investigating effects of general anisotropic fiber packing on stresses in composites.

Calculation of Stress Intensity Factors for a Thick Pipe Using Weight Function Method (가중함수법을 이용한 두꺼운 배관의 응력강도계수 계산)

  • Lee, Hyeong-Yeon;Lee, Jae-Han;Yoo, Bong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.7
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    • pp.2167-2173
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    • 1996
  • An approximate weight function technique using the indirect boundary integral equation has been presented for the analysis of stress intensity foactors(SIFs) of a thick pipe. One-term boundary integral was introduced to represent the crack surface displacement field for the displacement based weight function technique. An explicit closed-form SIF solution applicable to symmetric cracked pipes without any modification of the solution including both circumferential and radial cracks has been derived. The necessary information in the analysis is two or three reference SIFs. In most cases the SIF solution were in good agreement with those available in the literature.

A Experimental Study on the Hydroelastic Behavior of Large Floating Offshore Structures (대형부체구조물(大型浮體構造物)의 유(流).탄성(彈性) 연성거동에 관한 실험적 고찰)

  • Lee, Sang-Yeob
    • Journal of Korean Association for Spatial Structures
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    • v.1 no.2 s.2
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    • pp.101-110
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    • 2001
  • A large floating structure is attracting great attention in recent years from the view of ocean space utilization. Its huge scale in the horizontal directions compared with the wavelength and relatively shallow depth make this type of floating structure flexible and its wave-induced motion be characterized by the elastic deformation. In this paper, a boundary integral equation method is proposed to predict the wave-induced dynamic response mat-like floating offshore structure. The structure is modeled as an elastic plate and its elastic deformation is expressed as a superposition of free-vibration modes in air. This makes it straightforward to expand the well-established boundary integral technique for rigid floating bodies to include the hydroelastic effects. In order to validate the theoretical analysis, we compare with the experimental result of reduced model test. Satisfactory agreement is found between theory and experiment.

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A theoretical study on the hydroelastic behavior of Large floating offshore structures (대형부체구조물(大型浮體構造物)의 유체(流體)·탄성체(彈性體) 연성거동의 이론적 해석에 관한 연구(硏究))

  • Lee, Sang-Yeob;Rha, Young-Ho
    • Journal of the Korean Society of Industry Convergence
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    • v.4 no.4
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    • pp.433-439
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    • 2001
  • A large floating structure is attracting great attention in recent years from the view of ocean space utilization. Its huge scale in the horizontal directions compared with the wavelength and relatively shallow depth make this type of floating structure flexible and its wave-induced motion be characterized by the elastic deformation. In this paper, a boundary integral equation method is proposed to predict the wave-induced dynamic response mat-like floating offshore structure. The structure is modeled as an clastic plate and its elastic deformation is expressed as a superposition of free-vibration modes in air. This makes it straightforward to expand the well-established boundary integral technique for rigid floating bodies to include the hydroelastic effects. In order to validate the theoretical analysis, we compare with the experimental result of previous model test. Satisfactory agreement is found between theory and experiment.

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Eddy Current Analysis In Cover Plate of Power Transformers using Indirect Boundary Integral Equation Method (간접경계적분법을 이용한 변압기 cover plate에서의 와전류 해석)

  • Kim, Sang-Young;Kim, Dong-Hun;Han, Song-Yop
    • Proceedings of the KIEE Conference
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    • 1998.11a
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    • pp.88-90
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    • 1998
  • In this paper, the indirect BIEM(boundary integral equation method) is adopted to analyze 3-D eddy currents in cover plate of power transformer. In indirect BIEM, the equivalent magnetic surface charge density and the eqivalent magnanetic surface current density are the unknowns. Using triangular constant elements, the integral equations are discretized into boundary element equations of minimum order. Eddy currents are obtained in terms of euqivalent magnetic surface sources. And the locad overheating can be predicted using the eddy currents distribution in cover plate of power transformer.

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A Study on Mode III Kinked Crack Analysis Using Displacement-Discontinuity Method (변위 불연속 방법에 의한 모드 III 꺾인 균열 해석 연구)

  • 서욱환
    • Journal of Welding and Joining
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    • v.18 no.4
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    • pp.104-110
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    • 2000
  • An integral equation representation of cracks was presented, which differs from well-known "dislocation layer" representation. In this new representation, an integral equation representation of cracks was developed and coupled to the direct boundary-element method for treatment of cracks in plane finite bodies. The method was developed for in-plane (modes I and II) loadings only. In this paper, the method is formulated and applied to mode III problems involving smooth or kinked cracks in finite region. The results are compared to exact solutions where available and the method is shown to be very accurate despite of its simplicity.implicity.

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Development of a Numerical Method for Effective Elastic Analysis of Unbounded Solids with Anisotropic Inclusions (이방성 함유체가 포함된 무한고체의 효과적인 탄성해석을 위한 수치해석 방법 개발)

  • 최성준;이정기
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.04a
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    • pp.41-52
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    • 1998
  • A volume integral equation method and a mixed volume and boundary integral equation method are presented for the solution of plane elastostatic problems in solids containing orthotropic inclusions and voids. The detailed analysis of the displacement and stress fields are developed for orthotropic cylindrical and elliptic-cylindrical inclusions and voids. The accuracy and effectiveness of the new methods are examined through comparison with results obtained from analytical and boundary integral equation methods. Through the analysis of plane elastostatic problems in unbounded isotropic matrix containing orthotropic inclusions and voids, it is established that these new methods are very accurate and effective for solving plane elastostatic and elastodynamic problems in unbounded solids containing general anisotropic inclusions and voids or cracks.

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Application of Initial Stress Method on Elasto-plastic Problem in Boundary Element Method (경계요소법의 탄소성문제에 대한 초기응력법의 적용)

  • Soo, Lyong-Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.6 s.150
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    • pp.683-692
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    • 2006
  • The BEM, known as solving boundary value problems, could have some advantages In solving domain problems which are mostly solved by FEM and FDM. Lately, in the elastic-plastic nonlinear problems, BEM could provide the subdomain approach for the region where the plastic deformation could occur and the unknown nodal displacement of this region are added as the unknown of the boundary integral equation for this approach. In this paper, initial stress method was used to establish the formulation of such BEM approach. And a simple rectangular plate having a circular hole was analyzed to verify the suggested method and the result is compared with that from FEM. It is shown that the result of two methods are showing similar stress-strain curves at the root of perforated plate and furthermore the plastic deformation obtained by BEM shows more reasonable behavior than that of FEM.

A boundary element method based on time-stepping approximation for transient heat conduction in anisotropic solids

  • Tanaka, Masa;Matsumoto, T.;Yang, Q.F.
    • Structural Engineering and Mechanics
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    • v.4 no.1
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    • pp.61-72
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    • 1996
  • The time-stepping boundary element method has been so far applied by the authors to transient heat conduction in isotropic solids as well as in orthotropic solids. In this paper, attempt is made to extend the method to 2-D transient heat conduction in arbitrarily anisotropic solids. The resulting boundary integral equation is discretized by means of the boundary element with quadratic interpolation. The final system of equations thus obtained is solved by advancing the time step from the given initial state to the final state. Through numerical compuation of a few examples the potential usefulness of the proposed method is demonstrated.