• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.97-100
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• 2007

This study deals with the sound insulation performance of the damping sheet, which is widely used in a train. The wall of train is assumed to be a plate made of steel and two damping sheets. In case of damping sheet only, the sound transmission loss follows the mass law. If a steel plate is attached to damping sheet, the transmission loss is found to be higher than single of only steel plate, as we can anticipated, about $3{\sim}5$ dB. This is very well known consequence that is because the density of area increases. However, the increase of the transmission loss is not higher than what we can expect by the mass law. That's because the steel is perfectly blocked from the transmission of the air ; There is no defect in that material.

• 소음진동
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• 제8권6호
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• pp.1078-1085
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• 1998

This study is carried out to investigate the characteristics of sound insulation performances for masonry walls. PC walls and ALC walls. For these purposes. 17 types of masonry walls were selected and tested in accordance with KS F 2808 at reverberation room The sound insulation performance of 8" cement block walls are graded with D-45 ∼ D-55 which are to be evaluated very favorable grade. 4" cement block walls are D-30 ∼ D-40. 1 B cement brick walls are D-40∼D-50 favorable grade. 0.5 B brick walls are D-30∼D-45. 150 mm PC wall is D-50. and ALC walls(150 mm, 200 mm) are D-30∼D-45.

• KIEAE Journal
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• 제6권1호
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• pp.11-16
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• 2006

This paper deals with the experimental for manufacturing the lightweight buildng materials with portland cement, fly ash, slag, lime, gypsum, and aluminum powder system. Aluminum powder was added an aerating agent. Specific gravity range of lightweight concrete specimens were 0.6~0.9g/cm3. These specimens properties studied by means of specific gravity, compressive strength, absorption coefficient, transmission loss and scanning electron microscopy. Cellular concrete with maximum compressive strength was 41kgf/cm2 by obtained Al=0.05wt.%. Moreover, the aeration lightweight concrete showed excellent sound absorption properties.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.779-782
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• 2002

We examine the problem in which porous/viscoelastic compliant thin plates are subject to pressure fluctuations under transitional or turbulent boundary layer. Measurements are presented of the frequency spectra of the near-field pressure and radiated sound by compliant surface. A porous plate consisting of 5mm thick, open-cell foam with fabric covering and a viscoelastic painted plate of 1mm thick over an acoustic board of 4m thick were placed over a rigid surface in an anechoic wind tunnel. Streamwise velocity and wall pressure measurements were shown to highly attenuate the convective wall pressure energy when the convective wavenumber ($k_{ch}$) was 3.0 or more. The sound source localization on the compliant walls is applied to the measurement of radiated sound by using an acoustic mirror system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.1203-1209
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• 2001

Identification of noise sources, their locations and strengths, have been taken great attention. The method that can identify noise sources normally assumes that noise sources are located at a free field. However, the sound in a reverberant field consists of that coming directly from the source plus sound reflected or scattered by the walls or objects in the field. In contrast to the exterior sound field, reflections are added to sound field. Therefore, we have to consider the reverberation effect on the source identification method. The main objective of this paper is to identify noise source in the reverberant field. At fist, we try to identify noise sources in a rigid wall enclosure using the spherical beamforming method. In many case of practical interest, the wall has an admittance so that complex reflection process occurred. In this paper, we assumed the complex reverberant field in the enclosure to be the sum of plane waves with random incidence and magnitude. Then the effects of reverberant field at interior source identification have been studied theoretically as well as experimentally

• 한국소음진동공학회논문집
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• 제12권7호
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• pp.520-526
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• 2002

Identification of noose sources, their locations and strengths, has been taken great attention. The methods that can identify noise sources normally assume that noise sources are located in a free field. However, the sound in a reverberant field consists of that coming directly from the source plus sound reflected or scattered by the walls or objects in the field. In contrast to the exterior sound field. reflections are added to sound field. Therefore, we haute to consider the reverberation effect on the source identification method. The main objective of this paper is to identify noise source in the reverberant field. At fist, we try to identify noise sources in a rigid wall emc;psire using the beamforming method. In many cases of practical interest, the wall has admittance so that random reflections occur in an enclosure. In this paper, we assumed the complex reverberant field in the enclosure to be the sum of plane caves with random Incidence and magnitude. Then we try to explain effects of reverberant field at interior source identification.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.457-460
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• 2004

This study examines the sound insulation of the light-weight wall using light-weight concrete and offers the basic datum for enhancing it. The sound insulation of the light-weight wall is determinated by the density, installation method, absorption materials, air layers etc. Among the factors, the solution of outlet that is the major cause of reducing sound insulation should be made. If absorption materials are installed in the cavity walls, it enhances to 15dB in 500Hz.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.1044-1047
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• 2004

This aim of this study is is an experimental study to introduce the Reduction method of Floor Impact Sound in Apartment Houses by using Model Test, We are measured the floor impact sound in Rahamen and Apartment with Shear Wall and Post-tensioning. There is comparison between Rahmen Structure and Apartment with Shear Wall. The main results from this study are effective in reduction of heavt-weight The slab was constructed by rahamen structure. Heavy-weight can reduced by upgrading naturial frequency of floor impact sound in rahmen structure.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.1-1
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• 2014

Side scuttle in the shipboard windows is used in a smaller size in order to prevent damage to the glass. This shipboard windows should have high sound insulation performance (More than $R_w$ 53 dB) according to norsok standards. However, side scuttle having a small size and high sound insulation material is difficult to measure exact result without a suitable filler wall. In this study, the test was conducted according to the number of changes in the small window. As a result, before starting the test should be conducted to the selection of the suitable filler wall or secure a specimen area.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1383-1386
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• 2006

This study examines the difference of airborne sound isolation between laboratory and field test. The airborne sound isolation between adjacent dwellings in multi-family buildings is often much less than would be expected from the rated sound reduction index of the nominally-separating wall, due to structure-borne transmission of vibration at the junctions of wall. A variety of construction modifications to control such transmission have also been evaluated. This study presents a factor of the difference for flanking involving joint of wall, and shows the effect of some practical modifications that control the key flanking paths