• Proceedings of the KSR Conference
• /
• 2003.05a
• /
• pp.734-739
• /
• 2003

When a train moves on rails, wheel and rail vibrate to produce contact noise and contact force. The former results in airborne noise and the latter transmits through bogie and excites carbody to generate structure borne noise. In this paper, wheel vibration is studied by theoretical and experimental approaches. Theoretical analysis is performed by finite element method and experimental analysis is performed by impact test. Using modal analysis and model tunning, we could have good agreement between the two approaches.

• Journal of the Society of Naval Architects of Korea
• /
• v.45 no.6
• /
• pp.719-725
• /
• 2008

In this paper, noise and vibration reduction for floating-floored ship cabin is studied. A mock-up is built by using 6 mm steel plate, and two identical cabins are made for simulation of ship cabins. When a speaker is used as a sound and vibration sources, it is shown that floating floor is more effective in isolating sound than bare deck by 2-5 dB. It is also shown that structure-borne noise of the bare deck is greater than that of floating-floored deck by 3-10 dB. For tapping machine excitation, it is found that the effect of floating floor in airborne noise and structure-borne noise reduction reaches up to 40-50 dB for high frequency ranges.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.17 no.5 s.122
• /
• pp.437-447
• /
• 2007

A series of research to seek for the relationship between subjective responses and noise level for transportation noise have been proceeded, and their results showed similar for some cases and different for some other cases as well, which is considered due to the various conditions such as the way of survey, different scale applied, and country etc. This study aimed to analyze the relationship between sound level and subjective response for the different kinds of transportation noise. The noises recorded in real situation were played to thirty subjects with fourty nine adjectives. The percentage of people annoyed(% PA) and the percentage of people highly annoyed(% HA) were calculated from the subjective results and compared how many percent of people are annoyed and highly annoyed for the same sound level. As a result of calculating the average, the aircraft noise was highest and the white noise lowest. The relationship between window TL and average point was well correlated except the aircraft noise which was scattered because of high sound level at specific frequency and low TL at corresponding frequency. This means that appropriate rating method for airborne sound transmission should be sought for to evaluate outdoor noise which has different frequency characteristics. The Boltzmann equation for % PA and % HA was applied to predict the sound level corresponding to the percentage. It is concluded that the aircraft noise and road traffic noise have almost same response and the railway noise was same with white noise, used for the reference noise, annoyed lower than other noises about by 3 dB.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.12
• /
• pp.1096-1102
• /
• 2013

The useful practical land shall be reserved when an artificial land covers the railway and road. However, the problem is that since the artificial land places directly on the top of noise sources likely on the railway and road there will arise the weak points, noise and vibration. On this study based on creating the artificial land on the top of a railway vehicle base and placing a tenement on that land, it was comprehended the noise influence from the railway car through the simulation. In order to secure the input value for the simulation, at first measured the noise condition of the railway station building and the railway vehicle base. The output value for the railway station building (place A) was around (53.6~57.6) dB(A), the equivalent continuous sound level for an hour, and for the railway station building (place B) it was around (63.7~68.9) dB. The maximum outdoor noise of the tenement on the artificial land was measured as 64.1 dB(A) under the fixed condition on the simulation modeling. The built purpose of placing the artificial land to prevent the noise influence from the railway met the expectation to be less influenced on the tenement. Rather, because of placing the artificial land the noise level on the lower space could be increased so there requires having a noise control.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2004.07a
• /
• pp.322-322
• /
• 2004

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.11a
• /
• pp.380-383
• /
• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11b
• /
• pp.956-960
• /
• 2002

Offices and other multipurpose buildings commonly have suspended ceilings installed over room dividing wall. But Korean Standards don't include any code on test methods and test facility of the suspended ceiling system. Therefore, test methods and test facility from ISO and ASTM have been used for evaluating sound performance in domestic so fu. In this study, Korean Standards draft on test methods and test facility of suspended ceiling system and materials is proposed on the basis of ISO and ASTM.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.65-69
• /
• 2007

Recently, the method of the apartment building design is changing from wall type to moment structure. Because of this reason, dry wall systems are used plentifully. This study examines the sound insulation performance of the light weight concrete panel using bottom ash. There is the difference of airborne sound isolation between laboratory and field test. For the purpose of searching deviation, we use the prediction tool(Insul 6.0). First, we calculated the prediction data and 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 difference.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.10a
• /
• pp.1-1
• /
• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.10a
• /
• pp.296-297
• /
• 2013

We have investigated correlation between airtightness measured by blower door and airborne sound insulation measured in the upper and lower units. We consist of two cases : all windows sealed(CASE 1) and not sealed(CASE 2). As a result, CASE 1 is tighter than CASE 2 in airtightness, but CASE 1 is lower than CASE 2 in sound level difference. This is because of big wind on measuring CASE 1. Thus we are going to measure them at another fields considering this factor. Finally we ought to find out the correlation between airtightness and sound insulation.