• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.675-679
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• 2006

Today, the interior noise perceived by the occupants is an important factor in the design of automotive interior assemblies. Buzz, Squeak and Rattle Noises in a Seats are one of the major concerns mentioned above. In this study, the terms 'Buzz, squeak and rattle' were defined as the noise originating from structural vibrations in an assembly. And, the BSR noise of vehicle seat was investigated and the improvement of BSR noise level was confirmed though the structural treatment based on the structural analysis results from the modal and sound intensity of seat.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.380-383
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• 2006

This study examines the influence factor of flanking transmission in the wall. Generally, there is the difference of airborne sound isolation between laboratory and field test. The purpose of this study is examing the cause of droping sound insulation performance in the field and searching the method of improving sound insulation performance. First, we measured the sound isolation in the wall at the lab. Then, we measured it in the field and compared them. At the base of these datum, we measured the flanking transmission and solid transmission. For the flanking transmission am the wall, we used intensive method. So, we found the influence of solid transmission.

• 소음진동
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• 제8권2호
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• pp.289-296
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• 1998

To predict the noise propagation from an elevated railway, sound radiation characteristics of elevated structure are measured by using the sound intensity method. In the base of the results, we propose the source model of elevated structure noise and the calculation model for elevated railway noise. Acoustic model of the former is modeled a row of single sources with directivity cos .theta. positioned in the center of a bogie and arranged in the lower side of slabs. Also prediction model is presented with rolling noise and elevated structure noise calculated by considering the power level of a source for one-third octave band, ground absorption and barrier deflection. Noise level unit patterns of a passing train is calculated based on this model and the results are compared with available field data.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.956-959
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• 2007

The extension of a road system result from construction of the builling near the noise source as the roads, railroads. Many people who have a living space near the road are damaged by the noise generated the road system. Therefore, the damage will be reduced by the appropriate measure like putting some distance between receiver and source. The windows are weak among the building materials. But mainly we uses the windows as building exterior materials. So the sound insulation of the balcony windows was measured and compared.

• 대한조선학회논문집
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• 제40권1호
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• pp.36-46
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• 2003

To investigate the affection of lumped mass and spring on the vibration power flow of cross-stiffened plate experiencing bending vibration, structural intensity analysis is done using the modal analysis based on assumed mode method. The numerical analysis is carried out varying the mass and spring constant and their attached positions. The results show that both the spring and the mass may cause to large variation of not only vibratory displacement but also vibratory power flow patterns in case of little change of natural frequencies, and the attachments near to excitation location can effectively reduce the magnitude of maximum structural intensity.

• The Journal of the Acoustical Society of Korea
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• 제11권1E호
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• pp.50-55
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• 1992

팬의 익면 통과 주파수 소음은 총괄 소음 스펙트럼중에서 가장 명백한 성분이다. 그 소리는 일 반적으로 가장 불쾌한 성분이므로 저감이 요구된다. 따라서 그 소음치를 저감시키기 위해서는 정확한 축류형 팬의 소음원과 소음 방사 특성 규명이 요구된다. 본 연구에서는 푹류형 팬의 소음원과 소음 방 사 특성을 정의하였다. 음압 및 음향인텐시티를 이용한 음원 해석에서, 광센서를 이용한 축류형 팬의 동 기화가 수행되었고, 팬 날개에서의정확한 소음원의 위치를 결정하기 위해 Recording time의 결정이 제 안되었다. 팬 회전시, 소음원의 위치는 각 날개의 후단과 그 다음 날개의 선단사이에 각각 존재한다. 지 향성을 통하여 축류형 팬의 소음 방사 형태를 결정하였고, 벡터 에너지 흐름도로 음의 흐름을 가시화하 였다. 팬 익면에서의 회전 진동특성을 스트레인 게이지에 의하여 규명하였고, 또한 구조진동음의 음으로 의 기여도를 측정하였다. 또한 압전필름에 의한 팬 익면에서의 정압측정 가능성이 제시되었다.

• 소음진동
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• 제6권6호
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• pp.843-849
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• 1996

Locations and emission characteristics of noise source of motor vehicles are great important factors to control the road traffic noise in effective ways. From results of this study on emission characteristics of engine and exhaust noise, we could find that every noise emission of different kind of vehicles has smilar pattern. The main emission locations of engine noise for the front of vehicle became the space between the road surface and bottom of the body and radiator grill, and for the side of vehicle became the space between the road surface and bottom nearby the front wheel. In case of exhaust noise of passenger-car and light truck, all the highest sound intensity level located near surface of road. But it is hard to conclude the height of noise source of driving vehicles with only results of this study. So further studies are needed to check the emission characteristics of noise.

• 소음진동
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• 제6권6호
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• pp.692-700
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• 1996

소음원의 특성을 규명하는 방법론들을 각각 맵핑의 개념으로 통합하여 살펴 보았다. 방위각 추정 방법론에 근간을 둔 소음원 위치 탐지 방법과 같이 소음원의 등가 단극음원 크기 및 위치들을 추정하는 기본적인 방법들로 부터 보다 많은 계측 기기 및 탐촉자와 함께 상당히 정교한 데이터 처리를 수행하여야 하는 인텐시티를 이용한 음장 맵핑(mapping) 홀로그래피를 이용한 관심음장 전체의 3차원 맵핑 등 실로 다양한 방법을 관찰하였다. 결국은 가장 많은 탐촉자를 사용하는 측정 시스템이 보다 많은 음장의 정보를 제공하므로서 가장 탁월한 방법론이라 할 수 있다는 지극히 자연 스러운 결론을 낼 수 있다. 이것은 특히 탐촉자 자체의 가격이 저렴해져 가는 추세인 점과 소형화하는 추세를 감안하여 봄과 동시에 공간상의 물리적인 의미 즉 파수영역에 대한 보다 폭 넓은 이해를 통한 시간, 공간, 주파수, 파수영역 즉 확대된 차원에서의 음장, 소음에 대한 이해를 갖을 수 있다는 면에서 또다른 가치를 부여할 수 있는 것이다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.333.1-333
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• 2002

This paper suggests the noise reduction method of the engine cooling fan. It was estimated the fannoise contribution at the engine room and identified the noise source at the rotating fan by sound intensity method, first. And it has been developed the program for predicting the noise spectrum of axial flow fan. The radiated acoustic pressure is expressed the discrete frequency noise peaks at BPF and its harmonics and the line spectrum at the broad band by the noise generation mechanisms. In this paper it is shown that the comparison of the measuted and calculaed noise spectra of fn for the validation of the noise predictiong program. And this paper presents the characteristics of a fan noise due to modify the design parameters. Accordingly, it was obtained the design parameter values for noise reduction of fan.

• 한국소음진동공학회논문집
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• 제17권11호
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• pp.1013-1020
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• 2007

In this paper, the predictions and measurements of sound transmission loss(STL) are discussed for various types of acoustical materials and carpets. Random incidence sound transmission losses are measured by the sound intensity method. The in-house software HONUS2005 is used to predict TL and estimate the various physical properties such as the flow resistivity, the structure factor, the porosity, the Possion's ratio, and etc. After this estimation, various multi-layered materials with a steel plate are measured and predicted. In particular, Carpets are assumed to be membranes to predict acoustical performance. To confirm this assumption, double and triple-layered cases are also observed including two different kinds of carpets.