• The Journal of the Acoustical Society of Korea
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• 제11권2호
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• pp.38-49
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• 1992

The structure borne sound is one of the most important factor in building acoustics. Nevertheless, there is not yet sufficient knowledge to predict its behavior in preparing the acoustical design of a building. We are concerned with the concrete floating floor construction, which is one of the most promising ways to control floor impact sound. This study is to develop floating screeds isolated from the conventional concrete floor structures, to improve the concrete floor systems for the purpose of the good sound insulation performance which protects the propagation of the structure borne sound. Floor impact sound in many apartment house buildings and developed floating floors was measured, and we can save many floor impact sound data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 1993년도 춘계학술대회논문집; 한국과학연구소, 21 May 1993
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• pp.147-147
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• 1993

All types of dynamic excitation, periodical, pulse or transient in vertical, horizontal or all three directions can be effectively reduced by vibration isolation systems. Typical elements for vibration isolation control are spring units consisting of a group of helical compression springs. In all cases of shock, transient or random excitation energy absorbing dampers have to be added to the spring units in order to reduce system response in the frequency range near the natural frequency of the isolation system. The same isolation system of spring units and viscos-dampers has been used since 1979 for passive protection of buildings and structures has been proved to by very advantageous for vibration and structure borne noise control. Not only because of high vertical flexibility of the spring units, compared for example with typical rubber or neoprene mounts out also because of the horizontal of flexibility, which can be adapted by modifying the spring dimensions to nearly every requirement. It is just normal to use the same basic elements for passive isolation as for active isolation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.974-979
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• 2008

A design process for the structure-borne noise in a passenger vehicle is presented. The proposed process is improved from the previous one. The major difference between the current and last ones is that most of the countermeasures should be developed before fixing a tool for structural parts. This is requested for QCDP(Quality, Cost, Delivery and Productivity) by the design engineers. The proposed one consists of 4 steps: Problem definition, Cause analysis, Development of counter-measure and Validation. Based on the general rule: divide and conquer, the complex problem can be simplified into a few critical sub-systems through the first step: Problem definition. Secondly, the critical causes can be identified for the critical sub-systems through the second step: Cause analysis. Thirdly, effective countermeasures are investigated and produced through the third step: Countermeasure development. The proposed countermeasures are finally validated in the forth step: Validation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제15권2호
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• pp.161-168
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• 2005

The absorbing material is mostly used to changing the acoustic energy to the heat energy in the passive control, and that consists of the porous media. That controls an air borne noise while the stiffened plates, damping material and additional mass control a structure borne noise. The additional mass can decrease the sound by mass effect and shift of natural frequency, and damping material can decrease the sound by damping effect. The passive acoustic control using these kinds of control materials has an advantage that is possible to control the acoustic in the wide frequency band and the whole space at a price as compared with the active control using the various electronic circuit and actuator. But the space efficiency decreased and the control ability isn't up to the active control. So it is necessary to maximize the control ability in the specific frequency to raise the capacity of passive control minimizing the diminution of space efficiency such an active control. Therefore, the characteristics of control materials and the optimum layout of control materials that attached to the boundary of structure-acoustic coupled cavity were studied using sequential optimization on this study.

• Explosives and Blasting
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• 제31권1호
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• pp.23-32
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• 2013

Construction vibration such as explosive blast, hydraulic breaker, vibratory roller, pile driving noise and so on, injuries in areas around the construction sites. In particular, underwater sound caused by ground vibration is propagation such as structure borne noise. Vibration and underwater sound due to construction activities may cause injury to river, sea or land fish farms near construction sites. The purpose of present study is to measure the sound pressure level and frequency analysis of the underwater noise generated by ground vibration(Blasting, hydraulic crawler drill, hydraulic breaker, vibratory roller). Underwater noise were monitoring by a hydrophone (TC 4013) and recorded, analysis were made using a by software (Prosig).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.830-833
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• 2004

An indoor package air-conditioner (PAC) has complex noise sources such as motor noise and fluid noise caused by the fan motor, heat transfer and shroud. Sound intensity techniques and ODS(Operational deflection shape) techniques are applied to identify the noise characteristics of an indoor air-conditioner's cabinet. The sound intensity is used to visualize the noise source locations. and the ODS to visualize the vibration pattern and to obtain the dynamic characteristics of the noise source. Acoustic intensity and operational deflection distribution are obtained in space domains as well as frequency domains. Using the visual information of source locations and its dynamic characteristics, the damping patch is applied to reduce structure borne noise in the cabinet. As a result, the noise emitted by the cabinet is reduced by 5dB.

• Journal of KSNVE
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• 제11권2호
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• pp.187-195
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• 2001

승용차 실내소음은 소음의 전달 방법에 따라 구조기인소음(structure-borne noise)과 공기기인소음(air-borne noise)으로 구별된다. 구조기인 소음은 차체에 전달된 외력이 차체를 통하여 전달되고 전달된 차체의 진통이 최종적으로 차실을 이루는 패널의 진동을 일으켜 승객에 전달되는 소음이며 공기기인소음은 발생한 소읍이 공기를 타고 전파되어 차실을 투과하여 승객의 귀에 전달되는 소음을 말한다. 구조기인소음을 일으키는 기진력으로 엔진의 관성 및 폭발력, 노면의 입력, 구동계 진동, 풍력 등이 있다. 발생된 기진력은 엔진 마운트, 서스펜션 등을 통하여 차체에 전달되고 최종적으로 대쉬, 루프 등의 패널을 떨게 만들며 이러한 진동은 50∼500Hz 대역에서 차실 공간의 음향 특성에 따라 가감되어 저주파 실내 소음을 발생시킨다. 500Hz 이상 대역의 실내소음은 일반적으로 공기기인 소음이 대부분을 차치하게 된다.(중략)

• Journal of the Korean Society for Railway
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• 제2권3호
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• pp.18-25
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• 1999

A high speed train named Korean High Speed Train (KHST) with its maximum operating speed 350 km/h is now under development. For the successful design of a quiet and comfortable high speed train, it is important to understand the general features of the noise and vibration characteristics of high speed train. This paper reviews extensively collected materials on the noise and vibration characteristics of existing high speed trains. Based on the noise and vibration characteristics of TGV systems, a simple indoor-noise prediction rule is proposed for the TGV-type high speed trains such as KHST The indoor-noise of KHST at 350km/h is expected to be larger than at least 71 dBA. Some important researches conducted for designing KHST during last two years under the G-7 project are also briefly introduced at the last part of this paper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.1081-1085
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• 2002

A modeling is developed to predict the isolation performance of sound barrier systems under the sound pressure radiated from excited by point impact. The predicted results are compared with the measured results obtained by using APAMAT II. This instrument provides a combination of structure-borne noise and air-borne noise, which corresponds to rolling noise, by applying the excitation system projected steel balls against the steel sheet.

• Journal of KSNVE
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• 제7권2호
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• pp.293-300
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• 1997

Noise and vibration induced by subway operation is one of the major problem for the residents living nearby railway tracks. Many scientists and engineers have been working on proposing the more accurate prediction equation of noise and vibration to provide the better residential environment. Some predictiction equations were determined to compare the measurement value of a noise obtained from the inside of a residential area. It was observed that the condition of a soil type is one of the major parameter which should be considered to obtain the more accurate prediction value of a noise.