• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.7
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• pp.539-547
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• 2003

The prototype of Korean high speed train(KHST), composed of two power cars, two motorized cais and three trailer cars, has been designed, fabricated and tested. In this paper. the body vibration has been reviewed from the viewpoint of the vehicle's safety, the ride comfort and the vibration limits for components and sub-assemblies mounted on the car-body using by analytical method and experimental method. The on-line test of KHST has been tarried out up to 260 ㎞/h in the KTX line and the results of the on-line test show that KHST has no problems in the vehicle's safety. the comfort ride and the vibration limits at this speed. And the characteristics of body vibrations has been Predicted at 300 ㎞/h and 350 ㎞/h by fitting curve about the measured acceleration signals.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.3
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• pp.267-273
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• 2013

Recently, turbine-generators have been replaced for the integrity reinforcement and the efficiency improvement, also, the blade's failures of LP turbines due to torsional vibration have been reported. Excessive torsional vibrations can result in failures of components. The severity of torsional oscillations and stress depends upon the separation margin between the excitation frequencies and torsional natural frequencies. Therefore it is needed to measure the torsional natural frequencies after replacement of the components to conform the separation margin of torsional natural frequencies. In this study torsional vibration measurements were performed after LP turbine and generator replacement and the torsional natural frequencies for the turbine-generator train were calculated to evaluate the effects of generator replacement on torsional natural frequencies of turbine-generator train. It is expected that these evaluation results will be used effectively to identify the root causes of torsional vibration problems.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.4
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• pp.301-307
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• 2013

MRU(motor reduction unit) for KTX is a assembled complex structure that is equipped with a lot of parts at the express train KTX and that is the core power source operating variable speeds. This study is recorded the dynamic characteristics analysis results tested by EMA which is done through the parts and assembly test, transient analysis and stoped train test in order to design the online monitoring system for KTX MRU. And the mode shapes result from critical vibration frequency explain the relation with variable speeds of express train over 250 km/hr. Also these variable speeds make variable operational frequencies at pinion, axle gear mesh frequency and normal bearing fault frequencies. As the specified speed can make resonance with natural frequencies of the MRU, for the train operating stability, this study also presents the MRU's critical speeds calculated by the each train speed.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.167-175
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• 1999

This study was performed to evaluate the whole-vibration of the subway drivers. Measurement, evaluation and assessment were based on the ISO 2631. When the vibration levels of the drivers are compared with the health guidance caution zones of the ISO 2631, those of the drivers of the rail maintenance train and the number 3 subway line exceed the limit of the health guidance zones, while those of the drivers of other subway lines drivers are below the limit. This indicates that the rail maintenance train drivers are exposed to potential health risks.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.221-232
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• 1998

This paper introduces the outline of the ongoing G-7 project for the development of vibration and noise analysis and reduction technology for the Korea High Speed Train which will run at 350km/h. Extensively collected materials and data on the vibration and noise characteristics of high speed trains are summarized herein to reduce the research direction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.11
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• pp.1447-1453
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• 2012

For an electromagnetic suspension (EMS)-type urban Maglev train using U-shaped electromagnets, both the vertical and the lateral air gaps for levitation are maintained only by the electromagnet. The train can run over curved rails without active lateral air gap control because the U-shaped electromagnet simultaneously produces both a levitation force and a guidance force, which is dependent on the levitation force. Owing to the passive control of the lateral air gap, the lateral vibration could exceed the limits of the lateral air gap and acceleration. In this study, dynamic analysis of a Maglev train is carried out, and the effectiveness of a lateral damper for vibration reduction is investigated. To more accurately predict the lateral vibration, a Maglev vehicle multibody model including air-sparing, guideway irregularities, electromagnets, and their controls is developed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.4
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• pp.289-298
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• 2014

Pass-by noises of various trains were recorded by binaural recorder. The measured noises were evaluated using a sound pressure level and psychoacoustic metrics objectively. To analyze a binaural effect on annoyance that can be caused by train noise, auditory experiments were performed. Through the experiments, the annoyance differences between monaural and binaural train noises, the annoyance differences due to measurement angle and the annoyance differences due to kinds of train and measurement distance were determined. A correlation analysis was conducted to determine which index can affect the annoyance more strongly. As the result, a maximum rate of change of sharpness difference between left and right channels was proposed to predict the annoyance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1015-1021
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• 2001

This paper represents the results carried out to determine the dynamic response characteristics of Korea High Speed Rail(KHSR) bridges. The responses of the KHSR bridges subjected to the moving train loading are obtained through the simplified method for the 2-dimensional train/track/bridge interaction analysis in which the eccentricity of axle loads and the effect of the torsional forces acting on the bridge are included for the more accurate train/track/bridge interaction analysis. The results of the analyses are compared with the field test data to verify the performance of the 2-dimensional train/track/bridge interaction analysis method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.337.1-337
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• 2002

In order to control the railway noise, the radiation characteristic of the noise during the train passage should be analyzed. Generally, the major noise sources for Korean Train Express are the rolling noise and power unit noise up to 300km/h. 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. (omitted)

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.73-80
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• 2007

In this paper, the characteristics of noise and vibration of high speed train is analyzed depending on its speed. The speed is a very important parameter because it can affect the interaction between the train and the environment as well as the characteristics of the train itself. To measure its characteristics, we analyzed the signals from microphones and accelerometers which were attached to the passenger car of the high speed train. The signals from each sensor were stored in the recorder, and then analyzed by using the signal processing program. The data from each sensor are analyzed with the spectrogram. From the spectrogram, we found some distinct characteristics of the passenger car. Also, the characteristics of the noise propagation were inferred from the spectrogram.