• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.483-483
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• 2007

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1187-1190
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• 2009

CURVE SQUEAL NOISE IS THE INTENSE HIGH FREQUENCY TONAL THAT CAN OCCUR WHEN A RAILWAY VEHICLE TRAVERSES A CURVE OR A SWITCH. THE HIGH NOISE LEVEL CAUSES ANNOYANCE FOR PEOPLE WHO LIVE IN THE NEIGHBOURHOOD OF THE SQUEALING RAILWAY TRACK AS WELL AS FOR THE PASSENGERS IN CARS WITH CURVES. THIS PAPER EXAMINES THE SPECTRAL SOUND DISTRIBUTION IN CURVES FOR KTX TRAIN. THE FREQUENCY RANGE IS FROM AROUND 4,000 TO ALMOST 16,000Hz, WITH NOISE LEVELS UP TO 92dB IN CURVE R400.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.291-298
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• 1998

The object of this study is to investigate the effect of elastic wheel from the viewpoint of noise and vibration of railway vehicle. The vibration reduction was predicted from the FRF difference between elastic wheel and solid wheel by FEM simulation. The elastic wheel and solid wheel were compared in viewpoint of carbody vibration and car interior noise level. The effect of elastic wheel on the noise and vibration of subway vehicle was obtained. But, the application of elastic wheel must be reviewed in some aspect.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.577-583
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• 2002

We have made known the study of shape development of interference device for vehicle noise control. It's primary object greatly attenuate the noise due to transport vehicle by small products installed on the noise barrier edge. Also, it is able to improve the insertion loss of a noise barrier without increasing the height of noise barrier. The present time, we set up a newly manufactured products on the noise barrier edge and testify to it's the performance use of an experiment and evaluation for the reduction of railway noise. In this paper the frequency characteristic of interference device of noise barriers with attached newly developed products in terms of shape, absorptive material and split panel, are examined using field test around of railroad.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.114-119
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• 2003

Passengers are much interested in ineroir noise caused speed-up and mass reduction of railway vehicles. Generally, the major noise source for passenger cars are rolling noise and aerodynamic noise. The purpose of this paper is to evaluate the noise level and to analyze the noise sources for domestic and KTX trains. We also measured the interior noise and the rolling noise for passenger cars. In result, the noise level is below 65dBA for Seamaeul coachs, and below 66dBA for KTX coachs.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.618-626
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• 2011

Recent development of related technologies and efficient utilization of the entire country for the purpose of railway construction, and plans are being accelerated. the railway noise has been improved by increasing the high speed railway station, and accelerating the existing trains. Nord2000 which is an overseas noise prediction equation could not be applied directly to the domestic railway vehicles. So the specific vehicles in the Nordic countries which is a similar specification to domestic trains should be selected. Nord2000's accuracy was compared to Schall03, CRN's. Prediction of Ground impedance and Roughness class were carried out at different. In this paper, the result of selected vehicles for Nord2000 was as follows. S-1aX2 was for express trains, N-$^*2c$-3b was for Mugunghwa, S-Pass/wood was for Saemaul, N-4a was for freight trains, N-3a was for subway, the calculation time for Nord2000 took longer than others, in addition, Ground absorption was indispensable to calculate a noise map for Nord2000. As a result, CRN's prediction noise levels at Wonju-si was closest to the measurements. However, the predicted noise levels of Nord2000 was the most accurate.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.4
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• pp.531-536
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• 2003

In order to control the railway noise. we should know the radiation characteristic of the noise during the train passage Generally, the railway noise sources for conventional trains are classified by the rolling noise and power unit noise in tangent track. In this Paper. we describe on a train model that is considered to be a row of point sources to calculate the radiation characteristic The calculation results are compared with short distance measurement of three kinds of trains (EMU, Mookungwha, Saemaul). It is shown that the radiation characteristic of the rolling noise that is major noise source of electric multiple unit is dipole type. We know that characteristic of the engine noise is radiated as the cosine type.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.9
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• pp.1329-1334
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• 2013

A electric railway is unique system that electric trains consumed huge electric power are travelled and is much interested with EMC. There were several problems exceeding the standard in the frequency range of 9kHz to 150kHz because the radiation noises were moved the higher frequency range according to developing the power electronic technology. It is studied the experimental confirmation of main noise source on the electric train and the analytic simulation for reducing the noise level in this paper.

• Journal of the Korean Society for Railway
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• v.2 no.1
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• pp.28-37
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• 1999

Many residential areas are situated near to railroad tracks so that a railroad noise has been one of the major environmental issues. In this paper two important aspects have been investigated in order to properly evaluate the railroad vehicle noise : sound power levels for different types and sound propagation characteristics of the railroad vehicles. For noise source characteristics of railroad vehicles, sound power values for various types of trains that are in active service have been measured. In this paper, domestic railroad vehicles are measured and compared with high speed train(TGV). Based on sound power information of railway vehicles, prediction on the sound pressure level and equivalent noise level near to railway areas have been evaluated.

• Smart Structures and Systems
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• v.23 no.4
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• pp.347-357
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• 2019

A new methodology for mitigation of the wheel squealing is proposed and investigated based on the dithering control. The idea can be applied in railway lines particularly in urban areas. The idea is clearly presented, and applied to a validated model. A full-scale model including the vehicle, curved track and wheel/rail contact is developed in the time domain to analyze the possibility and level of wheel squeal noise. Comparing the numerical results with a field test, the model is validated in different levels namely i) occurrence, ii) squealing frequency and iii) noise level. Two different approaches are proposed a) dithering of the wheel with piezoelectric patches and b) dithering of the rail with piezoelectric stacks. The noise level as well as the wheel responses is compared after applying the control strategy. A parametric study is carried out and effect of the dithering voltage and frequency on the squealing noise is investigated. It is found that both the strategies perform quite effectively within the saturating threshold of piezoelectric actuators.