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목진용;김영국;박춘수;김기환
- Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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- 2004.05a
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- pp.200-205
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- 2004
The pantograph for Korean High Speed Train was developed and had been evaluating by through 'G7-R&D project for home grown high speed train technology' In this study, in mechanical aspect, the variation trend of contact force between pantograph and catenary according to the train running speed and driving pattern is conducted. A measuring system for current collecting performance and mechanical characteristics is used for this study, developed and installed on the prototype Korean High Speed Train, and physical characteristics were measured while the KHST runs on the test track. Through this study, remarkable trends of variation are found and analyzed from measured acceleration and vertical contact force between the pan head in pantograph and contact wire in catenary system according to the driving pattern and the train raised a running speed up to 300km/h.
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Gu, Dong-Sik;Kim, Jae-Gu;Choi, Byeong-Keun
- Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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- 2011.04a
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- pp.582-587
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- 2011
Acoustic Emission(AE) is widely used for early detection of faults for rotating machinery in these days because of its high sensitivity. AE signal has to need for transferring to low frequency range for the spectrum analysis included the fault mechanism. In transferring process, we lose a lot of fault information caused by unusable signal processing method. Discrete Wavelet Transform(DWT) is a method of signal processing for AE signatures, but the pattern of its mother function is not optimized with AE signals. So, we can lose the fault information when we want to use the DWT for AE signal. Therefore, in this paper, we will propose a novel pattern for DWT mother function, which is optimized with AE signals. And it will be applied to compare the results of DWT by daubechie and novel pattern.
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Heo, So-Jung;Kim, Min-Seong;Han, Hyung-Suk;Jeong, Weui-Bong
- Transactions of the Korean Society for Noise and Vibration Engineering
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- v.21 no.10
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- pp.916-923
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- 2011
The refrigerant after the expansion valve interchanges the heat at the evaporator. At this moment, the state of gas and liquid becomes two-phase flow and causes irregular noise. In order to avoid the noise, the two-phase flow pattern should be predicted. In this paper, the procedure to predict the two-phase flow patterns such as churn flow and annular flow was suggested using the CFD software. The experiments using refrigerant-supplying equipment was carried out and the noise levels according to the flow pattern were measured. The flow patterns predicted by this procedure showed good agreement with those by experiments. The churn flow is noisier than annular flow pattern.
https://doi.org/10.5050/KSNVE.2011.21.10.916 인용 PDF KSCI

Hwang, S.W.;Bang, M.J.;Rho, G.H.;Cho, C.T.
- Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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- 2006.05a
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- pp.340-343
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- 2006
As the needs of consumer on ride comforts increase and the reduction of road traffic noise tightened step by step, the power unit noise emitted by cars has been reduced. It has been found that tire noise dominates noise produced by the power-train when vehicles are driven at high speeds. Therefore, in these days, tire/pavement noise is concerned. Tire/pavement noise is affected by pavement type and vehicle???s transmission loss. Tire noise mechanism is produced by several mechanisms. The sound of tire can propagate either through the air or through the structure of vehicle. Pattern noise is the result of pressure variations through the air to the interior side of vehicle. Especially, on smooth asphalt the periodicity of tread design, pitch sequence is important factor, which have an influence on the reduction of tire noise.
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