• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.333-337
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• 2003

The use of reactive shearing structural intensity to place small patches of constrained layer damping material in order to achieve the largest reduction in the radiated sound power of Air-conditioner outdoor unit is described. The normal surface velocity of each panel was measured using a laser doppler vibrometer. Experimental results indicated that patches of constrained layer damping material placed over areas of high reactive structural intensity reduced the radiated sound power significantly more than patches of the same area placed over areas of low reactive structural intensity

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.116-122
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• 1995

본 논문에서는 컴프레서 쉘의 구조해석을 수행하기 위하여, 범용 구조 해석 패키지인 MSC/NASTRAN을 이용하여 컴프레서 쉘 전체의 동특성 해석을 수행하였으며, MSC/NASTRAN의 Superelement 모듈인 부분구조합성법을 이용하여 구조물 전체의 동특성해석을 수행하였다. 그리고, 각 분계의 변형 및 운동 에너지를 산출하여 전체 구조물의 고유모드에 대한 분계의 기여도를 평가하였으며, 각각의 에너지에 기여가 높은 분계의 형상을 변경하여 구조물 전체가 원하는 동특성을 얻도록 하였다.

• The Journal of the Acoustical Society of Korea
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• v.33 no.2
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• pp.111-117
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• 2014

In this paper, the structure-borne noise reduction on electrical equipment is discussed by the experimental analysis. The water cooling system in electrical equipment is the only noise source, so the mock-up was made to measure noise characteristics. Effects of power supply, stiffness, isolation of noise source and natural frequency determined by resilient mounts are investigated using the mock-up. The console prototype was made referring to noise reduction technique by the mock-up. The structure-borne noise level of a console prototype was measured and some experiments to reduce the noise was undertaken. The $1^{st}$ and $4^{th}$ harmonics of operating frequency of cooling fans causes highest structure-borne noise levels. The control of operating speeds of several DC cooling fan groups was tried. Also types and installation layouts of resilient mounts were investigated. To reduce structure-borne noise, followings can be applied: increase of stiffness, isolation of source, decrease of natural frequency of mount, combination of operating speed of fans, selection of mounts, and so on.

• Journal of the korean Society of Automotive Engineers
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• v.17 no.1
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• pp.20-30
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• 1995

제1부에서는 소음기를 구성하는 각종 기본요소의 구조에 따른 음향성능의 특성을 간략히 살펴보았고, 제2부에서는 소음기의 음향특성을 해석할 때 쓰이는 각종 성능지수의 정의와 계산상 처리방법에 관하여 토론을 하였다. 본 3부에서는 선형음향해석시에 관련된 각 요소당 관련변수에 대해 알아보고, 소음계 설계에 있어서 기본적으로 염두에 두어야 할 사항들에 대해 논의하고자 한다. 최근에는 컴퓨터 원용설계가 일반적으로 적극 수용되고 있으며 여기서는 이를 이해하기 위한 음향해석의 기본원리를 토론하고, 개념설계시에 사용되는 기본요소들의 기초적 특성에 대하여 언급하고자 한다. 1. 선형 음향해석. 1.1 일반적 가정. 1.2 선형모델에 포함된 소음계 요소의 기하학적 변수. 1.3 각 소음계 요소의 전달 매트릭스. 2. 가장 기초적인 일반 설계 지침.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.30 no.5
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• pp.51-55
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• 2001

일본의 도시바는 세계 최초로 독자적인 나선형 압축기구의 채용으로 밸브 없이 연속적인 압축이 가능한 헬리컬 압축기를 개발하였다. 이 압축기는 저소음, 저진동, 우수한 에너지 절약성, 콤펙트한 구조가 특징이다. 여기서는 상품개발 배경과 헬리컬 압축기의 구조, 특징등을 소개하고자 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.245-246
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.121-122
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• 2008

In this paper, computational analysis on the steady-state and transient behaviors of the valve system is discussed. Fluid-structure interaction (FSI) is taken into account using ADINA software. The computational results are experimentally validated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.411-412
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• 2012

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.336-342
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• 2018

Noise reduction is an important issue in auxiliary power unit(APU) of tracking equipments for using military. In this study, we designed and tested reduction methods of structure borne noise and airborne source noise at the auxiliary power unit. From the bench test results, it is found that the effect of noise reduction is about 22 dB(A) if the silencer is redesigned, which is the rescue structure. However, the influence of noise reduction by air is insufficient. In addition, it is confirmed that the effect of noise reduction is excellent when structure borne noise reduction is applied to the vehicle. We expected that the test results of this study are used as basic data to reduce the noise of other tracking equipment developed later.

• The Journal of the Acoustical Society of Korea
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• v.43 no.3
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• pp.277-284
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• 2024

This study proposes a method to predict noise reduction based on noise-reduction measures, using harmonic response analysis, for transformer design. The dynamic elastic coefficients of the components comprising the actual transformer were determined by manufacturing the materials of the transformer components into simple-shaped specimens, followed by a comparison of the modes between the experiments and the analyses. A finite element model of the transformer was implemented, and harmonic response analysis was performed by deriving the exciting force of the transformer. Subsequently, the theoretical sound power level of the transformer was derived from the results of the harmonic response analysis. Finally, noise reduction measures were established, and the noise reduction amounts were compared between the experiments and the analyses, before and after applying the measures. Through the comparison and analyses of the noise reduction measures, it was confirmed that the trends in the experiments and analyses matched.