• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.90-93
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• 2005

Power Flow Boundary Element Method(PFBEM) has been used as a promising tool for radiation problems in the midium-to-high frequency. PFBEM is the numerical method that applies boundary element technique to Power Flow Analysis (PFA). Indirect PFBEM is developed for acoustic scattering problems in the open field and in various frequency. To verify the analytic results of indirect PFBEM for acoustic scattering problems are compared with those of SYSNOISE, and the results using two analytic methods show a good agreement.

• 한국음향학회지
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• 제20권7호
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• pp.21-30
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• 2001

중고주파수 대역에서 구조물의 진동해석에 사용되는 새로운 기법인 파워흐름유한요소법과 음향방사문제를 해결하는데 사용되는 음향경계요소법을 이용하여 구조물의 진동해석에서 방사소음해석까지 일련의 과정이 순차적으로 이루어지는 해석시스템을 구축하였다. 평판으로 이루어진 임의의 형상 구조물의 진동해석을 수행하고, 이 때 얻어지는 표면에서의 에너지밀도를 음향해석을 위한 속도경계조건으로 활용하여 진동-소음해석을 수행하였다. 개발된 진동-소음해석 시스템의 검증을 위해 간단한 형상의 구조물을 모델링하여 상용화 패키지(SYSNOISE)의 해석결과와 비교하였으며 또한 여러 다양한 형상의 구조물에 대해서도 본 해석시스템을 적용하여 진동-소음해석을 수행하였다.

• 한국소음진동공학회논문집
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• 제21권10호
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• pp.967-974
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• 2011

The direct and indirect PFBEM(power flow boundary element method) for the treatment of the 3 dimensional multi-domain problems are proposed to predict the acoustic energy density in medium to high frequency ranges. In the proposed method, the equation is derived in a matrix form by considering coupled relationships of the power flow at the interface of given domains. The proposed method can successfully obtain the analytical solutions for the problems of coupled cubes and the small-scale reverberant chamber. Then the experiment is carried out to obtain STL(sound transmission loss) by using small-scale reverberant chamber and the results are compared with analysis results.

• 한국해양공학회지
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• 제26권4호
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• pp.30-36
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• 2012

Recently, the underwater radiated noises generated from large commercial ships have become a globally important issue. Countries with large ports and environmental protection organizations demand strict safety guidelines in relation to underwater radiated noise. In this paper, the coupled PFFE/PFBE method is used to investigate the vibration and underwater radiated noise of a commercial ship. PFFEM is employed to analyze the vibrational responses of the commercial ship, and PFBEM is applied to analyze the underwater radiation noise. The vibrational energy of the structure is treated as an acoustic intensity boundary condition of PFBEM to calculate the underwater radiation noise. Numerical simulations are presented for the commercial ship under various frequencies, and reliable results are obtained.

• 한국소음진동공학회논문집
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• 제22권11호
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• pp.1033-1041
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• 2012

Power flow analysis(PFA) is introduced for solving the noise and vibration analysis of system structures in medium-to-high frequency ranges. The vibration analysis software, $PFADS_{C++}$ R4 based on power flow finite element method(PFFEM) and the noise prediction software, $NASPFA_{C++}$ R1 based on power flow boundary element method(PFBEM) are developed. In this paper, the coupled PFFE/PFBE method is used to investigate the vibration and radiated noise of the rotary compressor. PFFEM is employed to analyze the vibrational responses of the rotary compressor, and PFBEM is applied to analyze the radiation noise around rotary compressor. The vibrational energy of the structure is used as an acoustic intensity boundary condition of PFBEM. Numerical simulations are presented for the rotary compressor, and reliable results have been obtained.

• 대한조선학회논문집
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• 제49권5호
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• pp.384-390
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• 2012

Power Flow Analysis (PFA) is introduced for solving the noise and vibration analysis of structures in medium-to-high frequency ranges. The vibration analysis software, $PFADS_{C{+}{+}}$ R4 based on Power Flow Finite Element Method (PFFEM) and the noise prediction software, $NASPFA_{C{+}{+}}$ R1 based on Power Flow Boundary Element Method (PFBEM) are developed. In this paper, the coupling equation which represents relation between structural energy and acoustic energy is developed for vibro-acoustic coupling analysis. And vibro-acoustic coupling analysis software based on PFA and coupling equation is developed. Developed software is composed of translator, cavity-finder, solver and post-processor over all. Translator can translate FE model into PFADS FE model and cavity-finder can automatically make NASPFA BE model from PFADS FE model for noise analysis. The solver module calculates the structural energy density, intensity of structures, the fictitious source on the boundary and the acoustic energy density at the field in acoustic cavities. Some applications of vibro-acoustic coupling analysis software to various structures and cruise ship are shown with reliable results.

• 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.

• 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.