• Title/Summary/Keyword: 경계요소법

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Maximum Run-Up Height of Single Waves (단일파의 최대 처오름높이)

  • Jo, Yong-Sik;Lee, Bong-Hui
    • Journal of Korea Water Resources Association
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    • v.30 no.5
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    • pp.487-493
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    • 1997
  • The maximum run-up heights of single waves are investigated in this study. A boundary intergral equation model is used to calculate the maximum urn-up heights of both solitary and N-waves. The effect of the bottom friction is considered in the model through a boundary layer theory. The calculated run-up heights are compared with available laboratory measurements, and other numerical and approximate analytical solutions. They are in good agreement.

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A Study for Mutual Interference Between Circular Inclusion and Crack in Finite-Width Plate by Boundary Element Method (경계요소법에 의한 유한폭 판재내의 원형 함유물과 균열의 상호간섭에 대한 연구)

  • 박성완
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.6
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    • pp.1474-1482
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    • 1994
  • In order to study the influence of a circular inclusion on a stress field neat a crack tip, mutual interference of a crack and the circular inclusion is analyzed by using the two dimensional boundary element method program made for the analysis of a bimaterial inclusion. The stress intensity factor of an inclusion which has small stiffness is a little greater than that of large stiffness in the near-by crack tip, and similar values tends to appear for distant crack tips. A line crack shows the repetition phenomena which caused by stress mutual interference depending on the radius and stiffness of an inclusion, and the repetition phenomena becoms weak in the inclusion which has large stiffness. Stress mutual interference shows repetition phenomena after extension of a line crack by the length of the radius of the inclusion which has small stiffness.

Direct Differentiation Method for Shape Design Sensitivity Analysis of Axisymmetric Elastic Solids by the BEM and Shape Optimization of Turbin Disc (경계요소법에 의한 축대칭 탄성체의 형상설계 민감도해석을 위한 직접미분법과 터빈 디스크의 형상최적설계)

  • Lee, Bu-Yun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.5
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    • pp.1458-1467
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    • 1996
  • A direct differentiationmethod is presented for the shape design sensitivity analysis of axisymmeetric elastic solids. Based on the exisymmetric boundary integralequaiton formulation, a new boundary ntegral equatio for sensitivity analysis is derived by taking meterial derivative to the same integral identity that was used in the adjoint variable melthod. Numerical implementation is performed to show the applicaiton of the theoretical formulation. For a simple example with analytic solution, the sensitivities by present method are compared with analytic sensitivities. As an application to the shape optimization, an optimal shape of a gas turbine disc toinimize the weight under stress constraints is found by incorporating the sensitivity analysis algorithm in an optimizatio program.

Treatment of Numerical Integration for Boundary Element Method (경계요소법에 있어서 수치적분에 관한 고찰)

  • Park, Sung-Oan;Kwak, Chang-Sup;Koo, Young-Duk
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.2
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    • pp.185-193
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    • 1996
  • Errors included in solutions obtained by the boundary element method are generally larger than those by the finite element method in the case that the number of discreted elements is small. One of the reasons is supposed to be attributed to the error which will be produced in the numerical integration of the singular functions in two dimensional elastic problem. Then, treatment of analytical integration to reduce computing time and to decrease errors of boundary element method are proposed.

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A Study on the Effect of Micro Defect on Stress Intensity Factor of Through-Crack by Boundary Element Method (경계요소법을 이용한 관통균열의 응력확대계수에 미치는 미소결함의 영향에 관한 연구)

  • Seong, Gi-Deuk;Yang, Won-Ho;Jo, Myeong-Rae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.3 s.174
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    • pp.560-566
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    • 2000
  • Many researchers have dealt with the problems of fracture mechanics. Generally, these researches are concerned with crack in isotropic material without other micro defects. Actual structure, however, may contain micro defects as well as crack in manufacture processing or operation. If it contains mi defects near a crack, some different characteristics will be appear in fracture behaviors of the crack. This study examines the effect of the micro defect on stress intensity factor of center slant crack rectangular plate subjected to uniform uniaxial tensile stress. In this study, boundary element method(BEM) is used for analysis in stress intensity factor(SIF).

Calculation of Effective Material Property for Multi-Grain Orthotropic Material by BEM (경계요소법에 의한 다결정 직교 이방성 재료의 유효 재료 상수의 계산)

  • Kim, Dong-Eun;Lee, Sang-Hun;Jeong, Il-Jung;Lee, Seok-Soon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.9
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    • pp.713-719
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    • 2008
  • Most of the MEMS parts are made of multi-grain silicon wafer, which is the orthotropic material and its material direction is arbitrary. The reliability of the parts must be guaranteed in order to use for the commercial usage. The need of the structural analysis of its parts emerges an important factor. The material properties of the MEMS parts are calculated by the numerical method in order to reduce a material test. In this study, the effective elastic modulus and its Poisson's ratio are calculated by the boundary element method(BEM) and are compared with the results by the finite element method(FEM).

Design of Interference Type Noise Barrier Using The BEM (경계요소법을 미용한 간섭형 방음벽의 설계)

  • Lee, Seung-Young;Lee, Sang-Kwon;Cho, Sung-Hwan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.374.2-374
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    • 2002
  • This paper investigates the insertion loss of nosie barrier with a intereference device. The efficiency of the conventional intereference-type noise barrier depends on specific frequency. Thus this study is performed to improve the efficiency of the rosie barrier in the range of broadband frequency, by changing the shape of intereference device and adding the channel with various depths. The boundary element method (BEM) is used to predict the insertion loss of noise barrier. (omitted)

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The Sound Field Reconstruction of a Korean Bell Using an Error Minimization Scheme in the BEM-Based Acoustical Holography (경계요소법에 기초한 음향 홀로그래피에서 오차 최소화 과정에 의한 한국 종의 음장 재구성)

  • 김철희;이장무;강연준
    • Journal of KSNVE
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    • v.9 no.1
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    • pp.131-140
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    • 1999
  • A method to reconstruct the sound field around a Korean bell is developed. The sound radiation problem is formulated based on the boundary element method by using the algorithm of the acoustical holography. Sound pressures at the hologram surface are measured and used as input data for the analysis program that was developed in this study. An error minimization scheme is presented to overcome difficulties that arise in the backward reconstruction of the BEM-based acoustical holography In the model fictitious source surfaces were also introduced to reduce the complexity stemmed from the source shape. The sound field associated with the (4.0) vibrational mode of the Korean bell was visualized and verified experimentally.

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Analysis of Mixed Mode Surface Crack in Finite-Width Plate Subjected to Uniform Shearing by Boundary Element Method (경계요소법에 의한 포물선형 인장과 비틀림을 받는 유한폭 판재의 혼합 Mode 표면균열에 대한 해석)

  • Park, Seong-Wan;Hong, Jae-Hak
    • Journal of the Korean Society for Precision Engineering
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    • v.7 no.4
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    • pp.103-116
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    • 1990
  • The mixed mode surface crack in finite-width plate subjected to uniform shearing has been analyzed in 3-D problem by using boundary element method. The calculations were carried out for the surface crack angles (${\alpha}$) of $0^{\circ}, 15^{\circ}, 30^{\circ}, 45^{\circ}, 60^{\circ}, and 75^{\circ}, $ and for the aspect ratio(a/c) of 0.2, 0.4, 0.6 and 1.0 to get stress intensity factors at the boundary points of the surface crack. For the aspect ratio of 1.0 and the surface crack angles, finite element method was used to check the results in this in this study. Comparison of the results from both method showed good agreement.

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Analysis of Mixed Mode Surface Crack in Finite-Width Plate Subjected to Uniform Shearing by Boundary Element Method (경계요소법에 의한 포물선형 인장과 비틀림을 받는 유한폭 판재의 혼합 Mode 표면균열에 대한 해석)

  • Park, Seong-Wan;Hong, Jae-Hak
    • Journal of the Korean Society for Precision Engineering
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    • v.7 no.4
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    • pp.117-129
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    • 1990
  • The mixed mode surface crack in finite-width plate subjected to uniform shearing has been analyzed in 3-D problem by using boundary element method. The calculations were carried out for the surface crack angles (${\alpha}$) of $0^{\circ}, 15^{\circ}, 30^{\circ}, 45^{\circ}, 60^{\circ}, and 75^{\circ}, $ and for the aspect ratio(a/c) of 0.2, 0.4, 0.6 and 1.0 to get stress intensity factors at the boundary points of the surface crack. For the aspect ratio of 1.0 and the surface crack angles, finite element method was used to check the results in this in this study. Comparison of the results from both method showed good agreement.

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