• 한국소음진동공학회논문집
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• 제23권4호
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• pp.315-323
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• 2013

Tire noise is divided into a road noise(structure-borne noise) and a pattern noise(air-borne noise). Whilst the road noise is caused by the structural vibration of the components on the transfer path from tire to car body, the pattern noise is generated by the air-pumping between tire and road. In this paper, a practical method to estimate the pattern noise inside a passenger car is proposed. The method is developed based on the sound intensity and airborne source quantification. Sound intensity is used for identifying the noise sources of tire. Airborne source quantification is used for estimating the sound pressure level generated by each noise source of a tire. In order to apply the airborne source quantification to the estimation of the sound pressure, the volume velocity of each source should be obtained. It is obtained by using metrics inverse method. The proposed method is successfully applied to the evaluation of the interior noises generated by four types of tires with different pattern each other.

• 한국자동차공학회논문집
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• 제6권1호
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• pp.182-195
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• 1998

The relation between the vibration induced from machinery and the radiated sound is complicated. Acoustic intensity method is widely used to obtain the accuracy of noise identification. In this study, as groundwork, the complex acoustic intensity method is performed to identify noise source and transmission path on different free space point source fields. From the numerical analysis for these simple fields, it is possible to predict the sound field characteristics which noise sources are related with each other, and certificate the validity of complex acoustic intensity. As an industrial application, the complex acoustic intensity method is applied a diesel engine to identify sound radiation characteristics in the near field.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.1053-1056
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• 2007

The acoustical performance of noise reducing devices installed on the top of a noise barrier were tested by small-scale outdoor tests. Noise measurements before and after installation of the devices were carried out using sound intensity methods. It is well known that the sound intensity method can specify the strength and directivity of sound, and it is convenient to consider the feature of sound around a noise barrier. The noise reduction effect of each edge device was evaluated using the difference between the input and output sound power levels calculated from sound intensities. It was investigated that each device had different efficiency in the shadow zone, while there was no significant difference between edge devices in the illuminated zone.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.171-171
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• 1997

Sound intensity distributions and energy flow in the near field of dipole source system and flat plate were investigated. First, the effectiveness of complex acoustic intensity was proved by using mathmatical and experimental methods in order to indentify noise sources and transmission paths of dipole field which is effected by the presence of neighbouring coherent sources. Next, analytical complex acoustic intensity method was discussed and the characteristics and energy flow of sound induced from the plate are clarified. The velocity of plate obtained from Finite Element Method was used for calculation of complex acoustic intensity in the near field. Finally experimental complex acoustic intensity method was applied to a passenger car. It can be seen that complex acoustic intensity method using both of active and reactive intensity is vital in devising a strategy for the identification and the reduction of vibration and noise.

• 한국음향학회지
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• 제6권3호
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• pp.17-22
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• 1987

새로운 차음성능 측정방법인 표면인텐시티법을 이용하여 실제 건축물의 현장에서 각부위별 차음성능 평가하고. 이를 종래의 음압측정방법과 은향인텐시티법 및 이론계산에 의한 결과 치 와 비교 . 검토하였다. 표면인텐시티법에 의한 건물부위의 차음성능 측정결과치는 음향인 텐시티법 및 이론계산에 의한 결과치와 잘 일치하였으며, 표면 인텐시티법은 음향인텐시티 법과 더불어 종래의 음압측정방법에 비해 측정시 주위 암소음 및 flanking transmission의 영향을 적게 받는 것으로 나타났다.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.159-171
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• 1997

Sound intensity distributions and energy flow in the near field of dipole source system and flat plate were investigated. First, the effectiveness of complex acoustic intensity was proved by using mathmatical and experimental methods in order to inden- tify noise sources and transmission paths of dipole field which is effected by the presence of neighbouring coherent sources. Next, analytical complex acoustic intensity method was discussed and the characteristics and energy flow of sound induced from the plate are clarified. The velocity of plate obtained from Finite Element Method was used for calculation of complex acoustic intensity in the near field. Finally experimental complex acoustic intensity method using both of active and reactive intensity is vital in devising a strategy for the identification and the reduction of vibration and noise.

• 대한기계학회논문집
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• 제10권5호
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• pp.601-610
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• 1986

본 연구에서는 음향학적 고찰로써 최근 디지를 처리기술의 발달에 따른 근접 한 2점의 음압으로 부터 테니스 라켓의 공기입자속도를 근사적으로 구하기 위하여 두 개의 마이크로폰을 이용하여 계산된 음향인텐시티는 구물의 오무드 해석법에 의해 구 해진 테니스 라켓의 동적 특성과 비교 검토함으로써 진동과 음의 발생기구를 구명하고 측정계의 비접촉에 의한 테니스 라켓의 동적 거동을 규명하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 춘계학술대회 논문집
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• pp.197-200
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• 2010

In some cases it is important to be able to measure not only the total sound intensity on a panel surface in a vehicle cabin, but also the components of that intensity due to sound radiation and due to absorption from the incident field. For example, these intensity components may be needed for calibration of energy flow models of the cabin noise. A robust method based on surface absorption coefficient measurement is presented in his paper.

• 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.

• 오토저널
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• 제8권4호
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• pp.43-55
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• 1986

소음저감에 대한 연구에서 소음언을 규명하기 위해서 소음의 발생 메카니즘을 안다는 것은 중요 하다. 구조물의 진동과 이로 인해서 발생되는 방사음과의 관계는 상당히 복잡하기 때문에 본 연 구에서는 음향인텐시티의 측정을 위하여 간단한 방사 모델을 대해 연구하였다. 소음원 규명의 첫 단계로서 본 연구에서는 음압측정에 의한 소음평가에 대해 알아 보았다. 두 번째 단계로서 음향 인텐시티법을 이용하여 음향 방사 모우드 패턴을 결정하였으며 음향인텐시티법이 소음원 검출에 유효함을 입증하였다. 또한 본 연구에서는 방진재 부착에 따른 음의 방사특성을 예측하고 방 진재 부착위치를 결정할 수 있었다.