• Title/Summary/Keyword: 경계요소법

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Three-Dimensional Boundary Element Analysis of Residual Stresses in Fiber Reinforced Viscoelastic composite Materials (섬유가 보강된 점탄성 복합 재료에 발생하는 잔류 응력의 3차원 경계요소 해석)

  • 이상순
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.12 no.3
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    • pp.309-317
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    • 1999
  • 이 논문에서는, 섬유가 보강된 직교 이방성 복합재료의 제작 과정에서 발생하는 잔류 응력을 조사하였다. 직교 이방성 복합 재료의 제작 과정은 경화 과정과 냉각 과정으로 나누어 지며 이 과정에서 발생하는 잔류 응력을 3차원 경계요소법을 이용하여 해석하였다. 모재는 선형 점탄성 거동을 한다고 가정하고, 종속 영역법을 도입하여 해석 모델을 섬유 영역과 모재 영역으로 나누었다. PATRAN을 사용하여 모재에서의 잔류 응력 분포를 도시하였으며 해석 결과를 검토하여 잔류 응력이 국부적으로 모재의 항복을 야기시킬 수 있음을 제시하였다.

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Modelling Technique and Model Analysis of Submerged Structures Using Finite Element Method and Boundary Element Method (유한요소법과 경계요소법을 이용한 수중에서의 탄성구조물의 진동모드해석 및 모델링 기법)

  • 김관주;오상륜
    • Journal of KSNVE
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    • v.10 no.2
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    • pp.319-324
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    • 2000
  • This paper shows hot to model the submerged elastic structures and adequate analysis tools for modal behavior when using finite element and boundary element method. Four different cases are reviewed depending on the location of the water and air. First case is that structures are filled with air and water is located outside. Second case is opposite to case one. These cases are solved by direct approach using collocation procedure. Third case is that water is located both sides of structures. Last case is that air is located both sides. These cases are solved by indirect approach using variational procedure. As analysis tools harmonic frequency sweep analysis and eigenvalue iteration method are selected to obtain the natural frequencies of vibrating submerged structures depending on the cases. Results are compared with closed form solutions of submerged spherical shell.

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The Analysis of Transmission Characteristics of Closed Structure with Internal Source Using FEM/BEM (유한.경계요소법을 이용한 내부음원을 갖는 닫힌 구조물의 차음 특성 해석)

  • Won, Sung-Gyu;Jung, Weui-Bong;Seo, Yeung-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.318-321
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    • 2005
  • In vibro-acoustic analysis, the commercial CAE tools, such as SYSNOISE, is usually used to take into account of the coupled effects of fluid acoustics and structural vibration. The acoustic field can be solved by either FEM or BEM, while the vibration field is usually solved by FEM. The interior or exterior acoustic problems with the coupled effects of the structural boundary could be solved by the commercial tools. The commercial tools, however, could not solve the problems in case that both the interior and exterior acoustic field is coupled with the structural boundary. In this paper, a realistic method based on FEM/BEM coupling scheme is presented to analyze the acoustic radiation from the internal source in a chamber to external acoustic field through elastic structural boundary. Several numerical examples are implemented to validate the developed program.

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Design of Interference Type Noise Barrier Using the BEM (경계요소법을 이용한 간섭형 방음벽의 설계)

  • 이상권;이승영
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.11
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    • pp.831-837
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    • 2003
  • This paper investigates the insertion loss of nosie barrier with a interference device, The efficiency of the conventional interference-type noise barrier depends on specific frequency, Thus this study is performed to improve the efficiency of the nosie barrierin the range of broadband frequency. by changing the shape of interference device and adding the channel with various depths, The boundary element method (BEM) is used to predict the insertion loss of noise barrier. Two-dimensional boundary element model is created to simulate the performance of long barrier with a line source.

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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    • 2003.05a
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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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A Complex Velocity Boundary Element Method for Nonlinear Free Surface Problems (복소 경계요소법에 의한 비선형 자유수면문제 연구)

  • Hong, Seok Won
    • Journal of Ocean Engineering and Technology
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    • v.4 no.1
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    • pp.62-70
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    • 1990
  • Cauchy의 적분공식을 복소속도(complex velocity)에 적용하여 포텐시얼 유동을 해석하는 복소경계요소법이 개발되었다. 이 결과로 얻어지는 적분방정식은 경계면에서의 접선속도(tangential velocity)와 법선속도(normal velocity)의 함수로 주어진다. 자유수면에서의 접선속도의 시간변화(evolution of tangential velocity)를 수식화하기 위하여 새로운 비선형 동역학적 자유수면경계조건(nonlinear dynamic free surface boundary condition)을 유도하였다. 복소포텐시얼 대신 복소속도를 이용하는 이 방법은 유장내의 특이점(field singularity)을 용이하게 고려할 수 있으며, 수치미분없이 직접 경계면에서의 유속을 해로서 구하게 된다. 그러나 자유수면이 존재하는 문제의 경우에는, 자유수면에서의 동역학적 경계조건을 만족 시키기 위한 계산과정에 접선 벡타의 변화량을 추정하는 것이 포함되게 되어, 계산과정이 다소 복잡하게 된다.

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Study on the Stress Singularity of Interface Crack by using Boundary Element Method (경계요소법을 이용한 계면균열의 응력특이성에 관한 고찰)

  • Cho, Chong-Du;Kwahk, Si-Young
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.4 s.97
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    • pp.197-204
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    • 1999
  • The boundary element method was used for studying singularities of an interface crack with contact zones. The iterative procedure is applied to estimate the contact zone size. Because the contact zone size was extremely small in a tension field, a large number of Gaussian points were used for numerical integration of the Kernels. Stress extrapolation method and J-integral were used ofr determining stress intensity factors. When the interface crack was assumed to have opened tips, oscillatory singularities appear near the tips of the interface crack. But the interface crack with contact zone which Comninou suggested had no oscillatory behavior. The contact zone size under shear loading was much larger than that under tensile. The stress intensity factors computed by stress extrapolation method were close to those of Comninou's solution. And the stress intensity factor evaluated by J-integral was similar to that by stress extrapolation method.

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An Analysis of Viscoelastic Problems by Boundary Element Method (경계요소법에 의한 선형 점탄성체의 해석)

  • 이상순;조덕상;손용수
    • Computational Structural Engineering
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    • v.7 no.2
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    • pp.69-75
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    • 1994
  • The procedure for the stress and displacement analysis of realistic viscoelastic materials by time domain boundary element method(BEM) has been discussed. The fundamental solutions and stress kernels have been obtained using the elastic-viscoelastic correspondence principle. The relaxation function is expanded in a sum of exponentials and the transformed fundamental solutions and stress kernels are inverted numerically into real time space. The proposed procedure requires a small computational effort and it is applicable in time domain boundary element analysis of realistic viscoelastic problems. Numerical results of example problem show the effectiveness and applicability of the proposed method.

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Accuracy analysis of a hydroelastic model of a floating beam (부유식 유탄성 보 모델의 수렴성 연구)

  • Kim, Ki-Tae;Lee, Phill-Seung;Park, Kwang-Chun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2011.04a
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    • pp.631-634
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    • 2011
  • 본 연구에서는 규칙 파랑 중에 있는 부유식 구조물의 유탄성 거동을 해석 하고, 수치모델의 수렴성을 살펴본다. 부유식 구조물은 보로 모델링 하며, 유체는 이상유체로 가정하여 문제를 해결한다. 보 모델의 경우 Euler-Bernoulli 보 모델과 Timoshenko 보 모델로 나누어 그 특성을 비교 해 본다. 문제의 해석법에 있어서 부유식 구조물의 경우는 유한요소법을, 유체의 경우는 경계요소법을 이용하여, 상호 연성된 방정식을 이끌어 낸다. 상호 연성된 방정식을 토대로 Euler-Bernoulli 보 모델과 Timoshenko 보 모델의 거동 특성을 살펴보고 제시된 수치 모델을 기준으로 수렴성을 분석해 본다.

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