• Title/Summary/Keyword: 경계요소법

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Analysis of Residual Stresses Induced during Adhesion Process of Chip and Leadframe (칩과 리드페임의 접착과정에서 발생하는 잔류 응력 해석)

  • 이상순
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.13 no.1
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    • pp.97-103
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    • 2000
  • This paper deals with residual stresses induced at the viscoelastic adhesive layer between the semiconductor chip and the leadframe during adhesion process. The adhesive layer has been assumed to be“thermorheologically simple”. The time-domain boundary element method(BEM) has been employed to investigate the behavior of interface stresses. Numerical results show that very large stress gradients are present at the interface corner and such singularity might lead to local yielding or edge delamination.

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Analysis of Ultrasonic Scattering Fields by 2-D Boundary Element Method and Its Application (2차원 경계요소법에 의한 초음파 산란음장의 해석과 응용)

  • Jeong, Hyunjo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.11 s.242
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    • pp.1439-1444
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    • 2005
  • A two-dimensional boundary element method was used for the scattering analysis of side-drilled hole(SDH). The far-field scattering amplitude was calculated for shear vertical(SV) wave, and their frequency and time-domain results were presented. The time-domain scattering amplitude showed the directly reflected wave from the SDH leading edge as well as the creeping wave. In an immersion, pulse-echo testing, two measurement models were introduced to predict the response from SDHs. The 2-D boundary element scattering amplitude was converted to the 3-D amplitude to be used in the measurement model. The receiver voltage was calculated fer SV wave incidence at 45$^{\circ}C$ on the 1 m diameter SDH, and the result was compared with experiment.

The Analysis of P-, and SV-Wave Response in the Homogeneous Half-Space Having Alluvial Deposit Arbitrary Shape (임의 형상의 퇴적층을 갖는 균일 반무한 영역내에서 P파와 SV파 응답해석)

  • 권영록;손영호
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.1
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    • pp.1-6
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    • 2001
  • P파와 SV파와 입사할 때 비균질 퇴적층에서의 지진응답을 유한요소법과 경계여소법을 조합하여 해석하였다. 유한요소법을 사용하여 불규칙한 기하형상과 비균질 재료 특성을 모델링하였고, 경계요소법을 사용하여 인위적인 경계로부터 불필요한 파의 반사를 없앨수 있게 반무한 영역을 모델링하였다. 경계요소의 기본해는 반무한 영역문제에서 반드시 고려해야하는 방사조건을 자동적으로 만족시킨다. 따라서 외부영역과 내부영역의 접촉면에서 표면력의 평행조건과 변위의 연속조건을 사용하여 P파와 SV파에 의한 지진응답을 해석하였다.

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The Analysis of SH-Wavw Response in the Homogeneous Half-Space Having Alluvial Deposit of Arbitrary Shape (임의 형상의 퇴적층을 갖는 균일 반무한 영역내에서 SH파 응답 해석)

  • 권영록;손영호
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.1
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    • pp.7-12
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    • 2001
  • 본 노문은 임의형상의 퇴적층을 갖는 반부한 영역내에서 SH하가 경사지게 입사할 때의 지진응답을 연구하였다. 그리고 비균질 퇴적층인 반무한 영역에서 파의 증폭을 다루었다. 사용한 수치해석 방법으로는 유한요소법과 경계요소법을 결합하여 수치해석하였다. 반무한 영역에서 자유장 응답과 정해를 비교 분석한 결과 잘 일치하여 검증되었다. 불규칙한 형상의 비균질 퇴적층을 갖는 부지에서의 지진응답 해석은 본 연구에서 개발한 수치해석 방법으로 가능하다. 따라서 임의 층상구조를 갖는 연약층에서의 SH파 증폭과 임의 각도와 입사하는 SH파에 대한 지진응답을 해석하였다.

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A Study on the Improvement of Vibration Environment by Wave Barrier (방진벽에 의한 진동 환경 개선 연구)

  • Huh, Young
    • Journal of the Earthquake Engineering Society of Korea
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    • v.4 no.4
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    • pp.63-71
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    • 2000
  • 대부분의 경우 지반을 통해 전달되는 진동을 줄이기 위해 사용되는 방진벽의 차진효율은 지반 위 한 점에서의 진폭저감계수로 표현되고 있다. 그러나 한 점에서의 진동차단 효율은 일정 지역의 평균값과 많은 차이를 보이고 있어, 일정 단지의 진동환경 개선에 요구되는 경우, 한 점에서의 값만으로 차진효율을 표현하는 것은 적합하지 않다. 이를 위해 본 논문에서는 단지 내 진동환경 개선의 판단방법을 제시하고, 방진벽의 기하학적 규모가 방진벽의 진동차단 효율에 미치는 영향을 경계요소법을 이용하여 구하였다. 해석결과에 의하면 강성 방진벽의 경우, 단면적인 방진벽의 차진성능에 큰 영향을 미치는 것으로 나타났다.

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Analyses of Stress Singularities on Bonded Interfaces in the IC Package by Using Boundary Element method (경계요소법을 이용한 반도체 패키지의 응력특이성 해석)

  • Park, Cheol-Hee;Chung, Nam-Yong
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.6
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    • pp.94-102
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    • 2007
  • Applications of bonded dissimilar materials such as large scale integration (LSI) 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 LSI. In order to investigate stress singularities on the bonded interface edges and delamination of die pad and resin in the IC package. In this paper, stress singularity factors(${\Gamma}_i$) and stress intensity factors($K_i$) considering thermal stress in the IC package were analyzed by using the 2-dimensional elastic boundary element method(BEM).

Viscoelastic Analysis for Behavior of Edge Cracks at the Bonding Interface of Semiconductor Chip (반도체 칩 접착 계면에 존재하는 모서리 균열 거동에 대한 점탄성 해석)

  • 이상순
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.14 no.3
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    • pp.309-315
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    • 2001
  • The Stress intensity factors for edge cracks located at the bonding interface between the elastic semiconductor chip and the viscoelastic adhesive layer have been investigated. Such cracks might be generated due to stress singularity in the vicinity of the free surface. The domain boundary element method(BEM) has been employed to investigate the behavior of interface stresses. The overall stress intensity factor for the case of a small interfacial edge crack has been computed. The magnitude of stress intensity factors decrease with time due to viscoelastic relaxation.

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Bragg Reflection of Obliquely Incident Waves (비스듬히 입사하는 파랑의 Bragg반사)

  • Jo, Yong-Sik;An, Yeong-Chang
    • Journal of Korea Water Resources Association
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    • v.35 no.1
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    • pp.91-96
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    • 2002
  • The present research describes the Bragg reflection of obliquely incident waves propagating over sinusoidally varying topographies. A numerical model based on the boundary element method is employed. Wave numbers providing Bragg reflection are calculated and compared to theoretical predictions. The reflection coefficients obtained from this model are also compared with those of the eigenfunction expansion method. A very good agreement is observed.

Shape Design Sensitivity Analysis of Two-Dimensional Thermal Conducting Solids with Multiple Domains Using the Boundary Element Method (경계요소법을 이용한 2 차원 복수 영역 열전도 고체의 형상 설계 민감도 해석)

  • 이부윤;임문혁
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.8
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    • pp.175-184
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    • 2003
  • A method of the shape design sensitivity analysis based on the boundary integral equation formulation is presented for two-dimensional inhomogeneous thermal conducting solids with multiple domains. Shape variation of the external and interface boundary is considered. A sensitivity formula of a general performance functional is derived by taking the material derivative to the boundary integral identity and by introducing an adjoint system. In numerical analysis, state variables of the primal and adjoint systems are solved by the boundary element method using quadratic elements. Two numerical examples of a compound cylinder and a thermal diffuser are taken to show implementation of the shape design sensitivity analysis. Accuracy of the present method is verified by comparing analyzed sensitivities with those by the finite difference. As application to the shape optimization, an optimal shape of the thermal diffuser is found by incorporating the sensitivity analysis algorithm in an optimization program.

Heat Conduction Analysis of the Cylinder Head in Turbocharged Gasoline Engine by Boundary Element Method (경계요소법에 의한 터보과급 가솔린기관 실린더헤드에 대한 열전도 해석)

  • 최영돈;홍진관
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.4
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    • pp.739-752
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    • 1989
  • The temperature distribution and heat flux of the inner wall of the cylinder of turbocharged gasoline engine were calculated by the 3-dimensional heat conduction analysis employing boundary element method. Overall mean effective heat transfer coefficient and thermal resistance ratio and equivalent thickness of the cylinder wall were calculated. the numerical results were discussed with respect to the engine speed, equivalence ratio, spark and boost pressure.