• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.488-492
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• 2007

Since Equipment-Noises occurring in machine room penetrate wall-body and travel to the adjacent room in the form of air-borne sound and structure-borne sound, it is appearing as the main factor that injures a peaceful residential environment, and due to this, such noise-damage is currently increasing rapidly. Consequently, despite the measures for sound-insulation and soundproof against the equipment-noise penetrated wall-body is urgently required, but as the subjective evaluation considered for psychological response about the equipment-noise was not practiced, many dissatisfactions are still raising even after some measure was taken. On such point of view, this Research, at the spot, has actually measured the equipment-noise that had permeated various wall-bodies, and examined its physical characteristics, thence based upon this, has conducted Psycho-Acoustics Experiment and investigated the interrelation between the physical evaluation value and psychological reaction value. It is considered that such study result could be utilized as the useful material at the time of establishment of the Grading Standard for the insulation performance against the Architectural Plumbing Noise, in the future.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.882-887
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• 2001

This paper deals with the effect of mass-spring-mass resonance that is a characteristics of the multi-layered panels in order to enhance sound insulation performance. From theoretical and experimental investigation, it is evident that tuning mass-spring-mass resonance by controlling elastic modulus of the core materials is very important to improve the STC value without increasing the weight of panels, resulting in enhancing STC value more than 10 dB.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.942-945
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• 2006

In order to measure the sound transmission loss(STL) of a test specimen such as windows, which is smaller than the test opening, a special partition is built into the test opening and the specimen is placed in that partition. This paper discusses how the measured STL is changed by the partition when a small-size window of high sound insulation is mounted. Theoretical and experimental investigations are carried out to quantify the effect of the filler wall. The results reveal that the smaller the window size is, the higher sound insulation performance of the filler wall is required in order to measure the accurate STL of the specimen. It is found that the insufficient sound insulation of the filler wall leads to the lower measured value of the window's STL.

• KIEAE Journal
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• v.9 no.1
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• pp.99-106
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• 2009

This study aims to survey the acoustical environment in the region around airport where there are various transportation noises such as aircraft noise, railway noise and traffic noise, and to analyze the subjective response on the noise to the people who live in house or work in office nearby airport. Measurement and subjective response evaluation were carried out at the same time and outdoor noise level was measured all day long to calculate one day results such as average Leq or one day WECPNL etc. The results showed that the military aircraft produces very high level comparing with commercial aircraft, for instance the sound level of commercial outdoor was lower than that of military aircraft indoor. Double and triple window were more effective for controlling the noise than single window, which showed the possibility of sound insulation treatment by installing windows having higher sound insulation performance. Finally the subjective response was resulted that the most annoying noise is from aircraft and counterplan they hope is 'airport moving out'. Leq 65 dB(A), the criteria value of sound insulation treatment, was corresponding to the subjective response of median annoyance '4' out of 7th scale.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.1
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• pp.139-146
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• 2011

In present study, it aims to compare the noise and vibration characteristics between magnesium alloy and steel hood panel. The AZ31 magnesium hood panel was fabricated through warm forming process, and the noise and vibration characteristics between both hood panels was compared through the measurement of engine radiation noise and transmission loss, as well as FRF on modal analysis. The sound insulation performance of magnesium alloy was wholly superior to that of steel hood panel, even though the transmission loss of magnesium alloy is lower than that of steel due to mass effect primarily. The FRF characteristics on modal analysis indicates that the resonance frequency of magnesium hood panel is remarkably increased to higher value than that of steel hood panel. The radiation and interior noise of magnesium panel even without acoustic hood insulation were remarkably lower than those of steel hood panel with acoustic insulation, in particular, at a range below 4,000 rpm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.153-158
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• 2007

Sound insulation performance of the flush door in the apartment unit was recently decreased due to the door for the purpose of barrier free. To evaluate sound insulation, the test for 13 kinds of flush doors was performed as aperture conditions under the flush door. and the measured value was compared with the predicted values of theoretical sound transmission. The results were summarized follow; First, in case of doors with aperture by barrier free, the single number quantities ($D_{pw}$) were evaluated $21{\sim}23dB$. Whereas, in case of existing door with frame, $D_{pw}$ was evaluated $28{\sim}31dB$. And in case of sealed doors, $D_{pw}$ was evaluated $31{\sim}34dB$. Second, the measured $D_{pw}$ was good agreement with the predicted $D_{pw}$ in condition of small aperture.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.177-182
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• 2000

This study aims to provide an effective method to reduce construction noise generated by breakers. To reduce the breaker's noise level, a sound encloser was developed; the sound insulation's performance was tested in the field. From the field test, the following results were obtained. The sound insertion loss was about 6.5dB(A), even though part of the sound encloser for the breaker was left unclosed. This is equal to the reduction value which can be obtained by using more expensive low noise breakers, proving that there are more effective measures for sound insulation at lower cost. The characteristic of frequency was evaluated to show an even reduction through all frequency bands, except 630Hz.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.483-484
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• 2010

Unit cabin means room, which is installed in the high value ship such as drill ship and FPSO, after pre-assembled. In order to develop the noise control design for a unit cabin, a variety of acoustic tests such as sound absorption, transmission, and radiated noise measurements were carried out by using the mock-up of living quarter. From the tests, it was found out that the combined noise level of a unit cabin could be dominated by the radiated noise from wall panel in low frequency range and the design guidelines for the noise control of unit cabin were fully established, such as the improvement of sound transmission loss between the cabin and corridor, and radiated cabin noise reduction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1083-1087
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• 2001

The purpose of this study is to obtain the basic data of existing light-weight Drywall through the evaluation and analysis of the light-weight drywall in reverberation chamber and to improve sound insulation performance of drywalls. Sound transmission loss of the total 11 types were analyzed in each frequency a-third octave band and evaluated sound insulation performance for each frequency. From data by analysis and calculation, STC value plotted on STC contour. We found that the improved light-weight drywall specimens ⓑ, ⓒ and ⓖ were satisfied with the domestic standard of sound transmission loss.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.12
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• pp.1210-1215
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• 2010

Unit cabin means room, which is installed in the high value-added vessel such as drill ship, offshore platform and FPSO, after pre-assembled. In order to develop the noise control design for a unit cabin, a variety of acoustic tests such as sound absorption, transmission and radiation measurements were carried out by using the deckhouse mock-up. From the tests, it was found out that the sound transmission loss between cabin and corridor was 13 dB below than FPSO standard and the combined noise level of the unit cabin was dominated by the radiated noise from wall panel in low frequency range. Based on the test results, design guidelines for the noise control of the unit cabin were fully established, such as the improvement of sound transmission loss between the cabin and corridor, and radiated cabin noise reduction.