• Title/Summary/Keyword: D-BEM

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Analysis on the Insertion Loss of a Noise Barrier by the Boundary Element Method (경계요소법을 이용한 방음벽의 삽입손실 해석)

  • 이우섭;정성수;황철호
    • Journal of KSNVE
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    • v.10 no.3
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    • pp.423-429
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    • 2000
  • This paper investigates the use of boundary element method(BEM) to analyze the insertion loss of a noise barrier. To begin with the validity of the BEm for the analysis of noise barrier insertion loss in checked by both Lam's theoretical method and the measurements in the anechoic chamber for the scale-down models. Through simulation it is shown that using 2D BEM model is sufficient to the analysis for the barrier with large ratio of length to height. By using 2D BEM model the insertion loses are predicted for the real noise barriers in several cases which are the case that they are built parallel on both roadsides the one that there are multiple sound sources and the one that there is a gap between a concrete structure and a barrier plate.

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Analysis and Propagation Behavior of Dissimilar Friction Welded Materials for Fatigue Crack in around Interface (이종마찰압접 계면근방에서의 피로균열의 전파거동 및 해석)

  • 오환섭
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1998.10a
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    • pp.140-145
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    • 1998
  • In this study, analysis for fatigue crack propagation behavior of interface and aroud interface under rotary bending stress. Though K values are nearly the same in around interface by BEM 2-D, fatigue crack propagated H.A.Z. Around Interface crack propagation speed is m=0.678 in H.A.Z by Paris' law. In this case(friction welded materials: STS304, SM15C), fatigue crack growth is considered SM15C metal microstructure and elastic flow from this result. Result is more metal microstructute dependence than stress dependence by analysis (BEM 3-D, BEM 2-D) and fatigue crack propagation

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An Analysis of the Sound Stopband in Periodically Corrugated 2-D Ducts (반복 주름을 갖는 이차원 덕트의 음파차단 해석)

  • Kim, Hyun-Sil;Kim, Jae-Seung;Kim, Bong-Ki;Kim, Sang-Ryul;Lee, Seong-Hyun
    • The Journal of the Acoustical Society of Korea
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    • v.31 no.1
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    • pp.11-18
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    • 2012
  • In this paper, the occurrence of a stopband phenomenon when an acoustic wave propagates through periodically corrugated ducts is discussed using theoretical and BEM analyses. A 2-D duct with sinusoidally corrugated upper and lower walls is considered. When the magnitude of the sinusoidal corrugation is sufficiently small compared to the duct's height, the wave equation is solved with the multiple scaling perturbation method. Then stopbands for Bragg and non-Bragg resonances are computed from the condition where frequency becomes a complex number. A 2-D BEM analysis is performed to compute insertion loss of the duct, and stopbands are confirmed as predicted by analytical analysis.

Tuning Fork Analysis using FEM and BEM (FEM과 BEM을 사용한 소리굽쇠 분석)

  • Jarng, Soon-Suck;Lee, Je-Hyeong;Park, Yeun-Young
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.401.2-401
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    • 2002
  • An unconstrained tuning fork with a 3-D model has been numerically analyzed by Finite Element Method (FEM) and Boundary Element Method (BEM). The first three natural frequencies were calculated by the FEM modal analysis. Then the change of the modal frequencies was examined with the variation of the tuning fork length and width. (omitted)

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The impact analysis of interface crack in dissimilar materials using the 2-D laplace transformed BEM (2차원 Laplace 변환 경계요소법에 의한 이종재료 접합면 균열의 충격해석)

  • 김태규;조상봉;최선호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.5
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    • pp.1158-1168
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    • 1994
  • For BEM analyses of the impact problems of dissimilar materials, the connected multi-region method using perfect bonded conditions on the interface boundaries was added to two-dimensional Laplace transformed-domain BEM program for a single region analysis. It was confirmed that the BEM results of impact problems of a single-region and multi-regions for a homogeneous isotropic material are agreed well. The two-dimensional Laplace transformed-domain BEM program combined with connected multi-region method was applied to analyse several impact problems of dissimilar materials. Also the feasibility of BEM impact analyses was investigated for dissimilar materials by the analysis of the BEM results for impact problems of dissimilar materials in terms of physical aspects. As for an application, the two-dimensional Laplace transformed BEM concerning impact problems of cracks at the interface of dissimilar materials and the determinating process of the dynamic stress intensity factors by extrapolation method are presented in this paper.

Tuning Fork Analysis using FEM and BEM (FEM과 BEM을 사용한 소리 굽쇠 분석)

  • Jang, Soon-Suck;Lee, Je-Hyeong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.1049-1053
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    • 2002
  • An unconstrained tuning fork with a 3-D model has been numerically analyzed by Finite Element Method (FEM) and Boundary Element Method (BEM). The first three natural frequencies were calculated by the FEM modal analysis. Then the change of the modal frequencies was examined with the variation of the tuning fork length and width. Analytical model equations were derived from the numerically relating results of the modal frequency-tuning fork length by approximating minimization. Finally the BEM was used for the sound pressure field calculation from the structural displacement data.

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A step-by-step approach in the time-domain BEM formulation for the scalar wave equation

  • Carrer, J.A.M.;Mansur, W.J.
    • Structural Engineering and Mechanics
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    • v.27 no.6
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    • pp.683-696
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    • 2007
  • This article is concerned with the presentation of a time-domain BEM approach applied to the solution of the scalar wave equation for 2D problems. The basic idea is quite simple: the basic variables of the problem at time $t_n$ (potential and flux) are computed with the results related to the potential and to its time derivative at time $t_{n-1}$ playing the role of "initial conditions". This time-marching scheme needs the computation of the potential and its time derivative at all boundary nodes and internal points, as well as the entire discretization of the domain. The convolution integrals of the standard time-domain BEM formulation, however, are not computed; the matrices assembled, only at the initial time interval, are those related to the potential, flux and to the potential time derivative. Two examples are presented and discussed at the end of the article, in order to verify the accuracy and potentialities of the proposed formulation.