• 제목/요약/키워드: Multi-domain BEM(Boundary Element Method)

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PFBEM을 이용한 자동차 실내외 다영역 공간의 소음해석 (Car Interior and Exterior Multi-domain Noise Analysis using Power Flow Boundary Element Method)

  • 김종도;홍석윤;이호원;권현웅
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 춘계학술대회논문집
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    • pp.489-493
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    • 2007
  • Mmulti-domain noise analysis method using Power Flow Boundary Element Method(PFBEM) has been developed successfully. Some applications are introduced. several examples. PFBEM is a numerical analysis method formulated by applying Boundary Element Method(BEM) to Power Flow Analysis(PFA). PFBEM is very powerful in predicting noise level in medium-to-high frequency ranges. However there are restrictions in analyzing the coupled structures and multi-media. In this paper, an analysis method for multi-domain acoustic problems in the diverse acoustic fields is suggested. And the developed method is applied to the car interior and exterior multi-domain noise analysis.

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Multi-Domain Structural-Acoustic Coupling Analysis Using the Finite Element and Boundary Element Techniques

  • Ju, Hyeon-Don;Lee, Shi-Bok
    • Journal of Mechanical Science and Technology
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    • 제15권5호
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    • pp.555-561
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    • 2001
  • A new approach to analyze the multi-domain acoustic system divided and enclosed by flexible structures is presented in this paper. The boundary element formulation of the Helmholtz integral equation is used for the internal fields and the finite element formulation for the structures surrounding the fields. We developed a numerical analysis program for the structural-acoustic coupling problems of the multi-domain system, in which boundary conditions such as the continuity of normal particle velocity and sound pressure in the structural interfaces between Field 1 and Field 2 are not needed. The validity of the numerical analysis program is verified by comparing the numerical results with the experimental ones. Example problems are included to investigate the characteristics of the coupled multi-domain system.

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Transmission Loss Estimation of Three Dimensional Silencers with Perforated Internal Structures Using Multi-domain BEM

  • Ju Hyeon-Don;Lee Shi-Bok
    • Journal of Mechanical Science and Technology
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    • 제19권8호
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    • pp.1568-1575
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    • 2005
  • The calculation of the transmission loss of the silencers with complicated internal structures by the conventional BEM combined with the transfer matrix method is incorrect at best or impossible for 3-dimensional silencers due to its inherent plane wave assumption. On this consideration, we propose an efficient practical means to formulate algebraic overall condensed acoustic equations for the whole acoustic structure, where particle velocities on the domain interface boundaries are unknowns, and the solutions are used later to compute the overall transfer matrix elements, based on the multi-domain BEM data. The transmission loss estimation by the proposed method is tested by comparison with the experimental one on an air suction silencer with perforated internal structures installed in air compressors. The method shows its viability by presenting the reasonably consistent anticipation of the experimental result.

DDM과 경계요쇼법을 이용한 동탄성 해석 (Transient Elastodynamic Analysis By BEM Using DDM)

  • 신동훈;박한규;박경호
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2009년도 정기 학술대회
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    • pp.534-535
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    • 2009
  • This paper deals with BEM analysis of transient elastodynamic problems using domain decomposition method and particular integrals. The particular method is used to approximate the acceleration term in the governing equation. The domain decomposition method is examined to consider multi-region problems. The domain of the original problem is subdivided into sub-regions, which are modeled by the particular integral BEM. The iterative coupling employing Schwarz algorithm is used for the successive update of the interface boundary conditions until convergence is achieved. The numerical results, compared with those by ABAQUS, demonstrate the validity of the present formulation.

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

  • 김태규;조상봉;최선호
    • 대한기계학회논문집
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    • 제18권5호
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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.

FEM-BEM iterative coupling procedures to analyze interacting wave propagation models: fluid-fluid, solid-solid and fluid-solid analyses

  • Soares, Delfim Jr.
    • Coupled systems mechanics
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    • 제1권1호
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    • pp.19-37
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    • 2012
  • In this work, the iterative coupling of finite element and boundary element methods for the investigation of coupled fluid-fluid, solid-solid and fluid-solid wave propagation models is reviewed. In order to perform the coupling of the two numerical methods, a successive renewal of the variables on the common interface between the two sub-domains is performed through an iterative procedure until convergence is achieved. In the case of local nonlinearities within the finite element sub-domain, it is straightforward to perform the iterative coupling together with the iterations needed to solve the nonlinear system. In particular, a more efficient and stable performance of the coupling procedure is achieved by a special formulation that allows to use different time steps in each sub-domain. Optimized relaxation parameters are also considered in the analyses, in order to speed up and/or to ensure the convergence of the iterative process.

A novel 3D BE formulation for general multi-zone domains under body force loading

  • Ghiasian, Mohammad;Ahmadi, Mohammad Taghi
    • Structural Engineering and Mechanics
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    • 제48권6호
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    • pp.775-789
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    • 2013
  • The current paper proposes a boundary element formulation, applicable to 2-D and 3-D elastostatics problems using a unified approach for transformations of the domain integrals into boundary integrals. The method is applicable to linear problems encompassing both finite and infinite multi-region domains allowing non-vanishing body forces. Numerical results agree quite well with the analytical solutions; while the present method offers easy formulation with less numerical efforts in comparison to FEM or some BEM which need interior points to treat arbitrary body forces. It is demonstrated that the method has the potential to have profound impact on engineering design, notably in dam-foundation interaction.

수중 프로펠러의 소음 예측에 관한 연구(Part 1. 비공동 소음) (Numerical Analysis of Underwater Propeller Noise(Part 1. Non-Cavitating Noise))

  • 설한신;이수갑;표상우;서정천
    • 대한조선학회논문집
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    • 제41권2호
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    • pp.21-32
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    • 2004
  • The non-cavitating noise of underwater propeller is considered numerically in this study. The main purpose is to analyze non-cavitating noise from underwater propellers in various operating conditions with different configurations. Noise is predicted by using time-domain acoustic analogy, boundary element method, and computational hydro-acoustics. The flow field is analyzed with potential-based panel method, and then time-dependant pressure data are used as the input for Focus Williams-Hawkings formulation to predict far field acoustics. Furthermore, boundary element method and computational hydro-acoustics are also considered to investigate duct propeller and ducted multi-stage propeller to consider the reflection and diffraction of sound waves. With this methodology, noise intensity and directivity of each noise sources could be well analyzed.

파워흐름경계요소법을 이용한 중고주파 소음해석 소프트웨어 'NASPFA' 개발 (Development of Noise Analysis Software-'NASPFA' in Medium-to-high Frequency Ranges using Power Flow Boundary Element Method)

  • 이호원;홍석윤;권현웅
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.949-953
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    • 2004
  • In this paper, Power Flow Boundary Element Method(PFBEM) is studied as the numerical method for the vibration and sound predictions of complex structures in medium-to-high frequency ranges. NASPFA, the sound analysis software based on PFBEM, is developed and is used for the vibro-acoustic analysis. And also the developed software is used for the prediction of interior and exterior sound fields of vibrating structures and for the analysis of the multi-domain problems. To verify the accuracy, NASPFA is applied to the prediction of the energy distribution in the simple structures, and its results are compared with exact PFA solutions. And various practical vehicle systems are modeled and the distributions of the acoustical energy density are successfully predicted.

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집적회로상의 선간 정전용량 계산을 위한 시뮬레이션에 관한 연구 (A Study on the Simulation of Interconnection Capacitance Calculation for VLSI)

  • 박화식;유동화;송영진;황호정
    • 전자공학회논문지A
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    • 제29A권1호
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    • pp.25-32
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    • 1992
  • In this paper, a method for the calculation of 2-dimensional interconnection capacitance for a multi-interconnection signal line in a dielectric region is presented. The numbers of dielectric layers and signal lines are arbitrary. To calculate the capacitance parameter, Boundary Element Method is used, and the dielectric interface and the surface of lines are divided into subsections. The advantages of BEM are small CPU-time and more exact solution due to the directly calculated values of capacitance only at the boundary of domain.It is adopted that the surface capacitance of each subsection assumed constant. The solution of surface charge density and capacitance parameter are calculated in a given domain.

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