• Title/Summary/Keyword: 경계요소법

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Dynamic Analysis of Surface Foundation Using Half-space Fundamental Solution (반무한체의 기본해를 이용한 표면 강체기초의 동적거동해석)

  • Lee Kangwon;Koh Jae-Pil;Cho Woo Yeon;Kim Moon Kyum
    • Journal of the Korean Institute of Gas
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    • v.5 no.3 s.15
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    • pp.51-54
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    • 2001
  • 지진 등과 같은 외부 진동하중에 의해 발생되는 구조물의 진동은 구조물의 독립적 거동뿐만 아니라 지반과 구조물 기초의 접촉면을 통해 상호 영향을 미치게 된다. 특히 LNG 저장탱크나 원자력발전소 등과 같이 대현 상부구조물의 경우 상호작용력은 크게 작용하게 된다. 본 연구에서는 상부 구조계의 단순화된 형태인 기초계의 동적거동을 파악하기 위해 주파수영역 경계요소법을 사용하여 수치적으로 연구하였다. 반무한체 상에 존재하는 무질량 강체 표면기초에 대해 반무한 기본해를 이용하여 동적거동이 고찰되었으며 기존의 해석결과와 비교, 검토하여 본 연구방법의 타당함을 입증하였다.

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Determination of Stress Intensity Factors for Bimaterial Interface Rigid Line Inclusions by Boundary Element Method (경계요소법을 이용한 접합재료 경계면의 직선균열형상의 강체 함유물에 대한 응력세기계수 결정)

  • Lee, Kang-Yong;Kwak, Sung-Gyu
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.176-181
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    • 2000
  • Stress intensity factors for a rigid line inclusion tying along a bimaterial interface are calculated by the boundary element method with the multiregion and double-Point techniques. The formula between the stress intensity factors and the inclusion surface stresses are derived. The numerical values of the stress intensity factors for the bimaterial interface rigid line inclusion in the infinite body are proved to be in good agreement within 3% when compared with the previous exact solutions. In the finite bimaterial systems, the stress intensity factors for the center and edge rigid line inclusions at interface are computed with the variation of the rigid line inclusion length and the shear modulus ratio under the biaxial and uniaxial loading conditions.

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Prediction of crack propagation path in IC package by BEM (경계요소법에 의한 반도체 패키지의 균열진전경로 예측)

  • Song, Chun-Ho;Chung, Nam-Yong
    • Proceedings of the KSME Conference
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    • 2001.06a
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    • pp.286-291
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    • 2001
  • Applications of bonded dissimilar materials such as IC package, ceramic/metal and resin/metal bonded joints, are very increasing in various industry fields. It is very important to analyze the thermal stress and stress singularity at interface edges in bonded joints of dissimilar materials. In orer to understand the package crack emanating from the edge of Die pad and Resin, fracture mechanics of bonded dissimilar materials and material properties are obtained. In this paper, the thermal stress and its singularity index for the IC package were analyzed using 2-dimensional elastic boundary element method. Crack propagation angle and path by thermal stress were numerically simulated with boundary element method.

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Prediction of Crack Propagation Path Using Boundary Element Method in IC Packages (반도체 패키지의 경계요소법에 의한 균열진전경로의 예측)

  • Chung, Nam-Yong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.3
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    • pp.15-22
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    • 2008
  • Applications of bonded dissimilar materials such as integrated circuit(IC) packages, ceramics/metal and resin/metal bonded joints, are very increasing in various industry fields. It is very important to analyze the thermal stress and stress singularity at interface edge in bonded joints of dissimilar materials. In order to investigate the IC package crack propagating from the edge of die pad and resin, the fracture parameters of bonded dissimilar materials and material properties are obtained. In this paper, the thermal stress and its singularity index for the IC package were analyzed using 2-dimensional elastic boundary element method(BEM). From these results, crack propagation direction and path by thermal stress in the IC package were numerically simulated with boundary 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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The Effect evaluation of the hole near a crack tip by Boundary Element Method (경계요소법을 이용한 균열선단 원공의 영향 평가)

  • 이대영;김성재
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.434-439
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    • 2000
  • In this paper, in order to study the geometric factor effect of a circular hole near a crack tip in a semi-infinite plate, the Dimensionless Stress Intensity Factor, $F(=\frac K {\sigma {\sqrt{\pi a}}})$ is analyzed at the crack tip using a two Dimensional Boundary Element Method (BEM) program which is known as superior in Fracture Mechanics. Kelvin's solution was used as a fundamental solution in BEM analysis and displacement extrapolation method was used to determine Stress Intensity Factor.

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Analyses of Stress Intensity Factors for Slant Crack Emanation from Circular Inclusion by Boundary Element Method (경계요소법에 의한 원형함유물에서 파생되는 경사균열의 응력확대계수 해석)

  • Park, Sung-Oan;Hwang, Soon-Won
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.7 no.5
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    • pp.72-84
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    • 1998
  • In order ot study the influence of a circular inclusion on a stress field near a crack tip, mutual interference of a slant crack and the circular inclusion is analyzed of a bimaterial inclusion. As the crack emanates at the equivalent slant crack angle the correction factors FⅠ and FⅡ for the inclusion wit small Young's modulus were found to decrease as the inclusion radius increased. The correction factors for inclusion with large Young's modulus increase as the inclusion radius increases at the equivalent radius of the inclusion, the correction factors decrease as the slant crack angle increases for the aspect ratio $\frac{c}{W}$ = 0.1 irrespective of the Young's modulus. For $\frac{c}{W}$ greater than 0.2, they increase as the slant crack angle increases. There is no influence of stress mutual interfce after crack emanates beyond the inclusion radius.

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A comparison of the transmission losses of two-dimensional dissipative silencers predicted by analytical method and BEM (이론적 해 및 경계요소법에 의한 2차원 흡음형 소음기의 전달 손실치 예측 비교)

  • 김회전;이정권;정지훈
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1001-1004
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    • 2002
  • Accurate prediction of the transmission loss of dissipative silencers has been considered difficult due to the ambiguity and complexity in the physical properties of sound absorbing materials. Additional difficulty lies in the fact that the analytical calculation of the propagation constant is unknown yet. In this paper. as a first step toward obtaining the Propagation constant and thus predicting the transmission loss, an approximation equation stemming from the wave analysis in the lined interior has been derived. Such an analytical solution and numerical solution using the boundary element method are compared for a two-dimensional simple dissipative silencer under the assumption of the locally reacting sound absorbent.

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An Analysis of Acoustic Field for Turbo Chiller Discharge Duct by Using Boundary Element Method (경계요소법을 이용한 터보냉동기 덕트의 내부 음향장 해석)

  • 전완호;이준근;정필중
    • Journal of KSNVE
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    • v.10 no.6
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    • pp.963-970
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    • 2000
  • The turbo chiller uses centrifugal compressor, which operates at about 14,500 rpm. Due to the high rpm of the impeller, the noise of chiller males one of the serious problems. The possibility of the sound reduction by using absorbing material is studied in this paper. The generated sound propagates through the duct and then radiates to the outer field. So, the use of sound absorption material inside the duct is one of the effective methods. To study the effect of location of the material, we use Boundary Element Method to analyze the sound field inside the duct system. Numerical study shows the highest sound pressure region is near the elbow of curved duct. From the numerical study, it is also shown that appropriate use of sound absorbing material at this region makes 8dB reduction of the highest noise level.

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A Study on Stress Distribution Using Boundary Element Analysis Due to Surface Coating in Sliding Contact (경계요소법을 이용한 미끄럼 접촉을 받고 있는 코팅층의 응력분포에 관한 연구)

  • Lee, Gang-Yong;Gang, Jin-U
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.2
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    • pp.304-311
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    • 2001
  • The present work examines the influence of surface coating on the temperature and the thermo-mechanical stress field produced by friction due to sliding contact. A two-dimensional transient model of a layered medium submitted to a moving heat flux is prsented. A solution technique based on the boundary element method employing the multiregion technique is utilized. Results are presented showing the influence of coating thickness, thermal properties, Peclet number, and mechanical properties. It has been shown that the mechanical properties and thickness of coating have a significant influence on the stress field, even for low temperature increase. The effects of the ratios of shear modulus become more important for low temperature increase than the effects of the ratios of other mechanical properties.