• Computational Structural Engineering
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• v.7 no.2
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• pp.77-87
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• 1994

Vibrational analysis of slab tracks for HSR(High Speed Rail) is performed in order to find dynamic characteristics and to control noise and vibration for the tracks. Wheel-rail interactive force is included in the analysis by modelling the vehicle and track as an unsprung mass and elastically-supported-double-beam respectively, and both are assumed to be connected by the Hertzian spring. From this study, it has been found that vibration in the track and the force transmitted to the infrastructure could be reduced by controlling elasticity, mass and stiffness of the track supporting system appropriately.

• Journal of the Korean Geotechnical Society
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• v.16 no.4
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• pp.71-82
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• 2000

Ground vibration analysis methods for Light Rail Transit(LRT) on bridges are studied. LRT loads acting on the piers are evaluated considering interactions between trains and a bridge. Two dimensional in-plane and axisymmetric wave propagations are used in ground vibration analyses, and then the results of them are compared one another. A modified axisymmetric method is presented, which can consider the effect of the train loadings on a series of piers as the train moves. Parametric studies are carried out for various train speeds, bridge types and geotechnical conditions to investigate the characteristics of ground vibrations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.459-462
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• 2005

The KHST(Korean High Speed Train) which had been developed by through 'G7-R&D project' has succeeded trial running test up to 350km/h on the Kyoung-Bu High Speed Track in December 16th, 2004. In order to evaluate the function and characteristics of KHST, various experimental conditions have been considered and conducted. In this paper, measured current collection characteristics and dynamic behaviors of KHST's pantograph are analysed over 300 to 350km/h in running speed of KHST. A measuring system developed and installed on the KHST for measuring the performance and mechanical characteristics of the KHST's pantograph was used for this trial running test and eventually, we proofed that KHST has a remarkable and stable current collection characteristics as it had been designed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.7
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• pp.253-260
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• 2001

A Study of interior noise reduction in the magelv train is presented. Tarin speed of interest is low such that aero-dynamic noise is negligible and power supply system is a dominant noise source. Based on the measurements of interior noise and acceleration levels during running and zero speed conditions, dominant noise sources are identified. After spectra characteristics of noise sources are investigated several noise reducing methods are studied such as STL increasement of floor panels. sealing. and absorption treatment It is found that the most important noise sources are VVVF inverter and SLM in running condition, whereas air conditioner and DC/DC converter are dominant in zero speed. Sine the major noise sources are under the floor complete sealing and high STL of the floor panel are shown to be the most crucial factors in noise reduction After sound absorbing material, which is polyurethan foam of 50 mm thickness, is thickness, is attached to the downward side of the floor in addition to sealing treatment, the interior noise is reduced by 3~4 dB.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.3
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• pp.253-260
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• 2014

conducted. In-situ measurements were conducted to investigate the noise characteristics in high-speed trains such as KTX and KTX-Sancheon. Binaural microphones and spherical microphone were adopted to record and evaluate the spectral characteristics and noise incidence characteristics at the seats in the passenger cars. Environmental elements were also recorded during the noise measurements using a camcorder and GPS application. In addition, auditory tests were conducted to investigate annoyance of interior noise of high-speed trains. Based on the objective measure and subjective responses on interior noise, statistical analysis such as correlation and regression analyses were carried out. From the results perception models for evaluating the interior noise of high-speed train were derived.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.147-152
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• 2012

An instantaneous environmental noise simulation method emitted by a moving high-speed train by quasi-stationary analysis is proposed in this study. In the method, the propagation attenuations from stationary point sources on segmented railways to a receiver are calculated using a general purpose environmental noise prediction program ENPro based on the ISO 9613-2 method. Then, the instantaneous environmental noise at a receiver due to a moving high-speed train considering convection effect is evaluated with the information on the propagation attenuations from the instantaneous train location to the receiver and the sound power levels and directivity of stationary point sources evaluated by German Schall 03 (2006). To demonstrate the validity of proposed method, simulated and measured time history of instantaneous noise for KTX-I and KTX-II on running are compared and the results show that the method can be utilized for the train noise source identification as well as the simulation of instantaneous environmental noise emitted by a high-speed train.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1152-1160
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• 2007

In this paper we deal with a design of integral sliding mode controller to reject the disturbance force acting on the suspension system in the magnetically levitated system which is propelled by the linear induction motor. The control scheme comprises an integral controller which is designed for achieving zero steady-state error under step disturbances, and a sliding mode controller which is designed for enhancing robustness under plant uncertainties. A proper continuous design signal is introduced to overcome the chattering problem. The disturbance force produced by the linear motor is formularized by using a curve fitting of the experimental raw data. Computer simulations show the effectiveness of the designed integral sliding mode controller to reject the disturbance force.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.157-164
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• 2005

Urban conditions such as underground facilities and ambient noises due to cultural activity restrict the application of conventional geophysical techniques in general. We used the refraction microtremor (REMI) technique as an alternative way to get the geotechnical information, in particular shear-wave (S-wave) velocity information, at a site along an existing rail road. The REMI method uses ambient noises recorded using standard refraction equipment to derived shear-wave velocity information at a site. It does a wavefield transformation on the recorded wavefield to produce Rayleigh wave dispersion curve, which are then picked and modeled to get the shear-wave velocity structure. At this site the vibrations from the running trains provided strong noise sources that allowed REMI to be very effective. REMI was performed along the planned new underground rail tunnel. In addition, Suspension PS logging (SPS) were carried out at selected boreholes along the profile in order to draw out the quantitative relation between the shear wave velocity from the PS logging and the rock mass rating (RMR) determined from the inspection of the cores recovered from the same boreholes, These correlations were then used to relate the shear-wave velocity derived from REMI to RMR along the entire profile. The correlation between shear wave velocity and RMR was very good and so it was possible to estimate the RMR of the total zone of interest for the design of underground tunnel,

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.532-542
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• 2018

Because maglev trains have a propulsion and absorption force without contact with the rails, they can drive safely at high-speed with little oscillation. Recently, test model of a maglev propulsion train was produced and operated, and has since been chosen as a national growth industry in South Korea; there have been many studies and considerable investment in these fields. This study examined the dynamic responses due to bridge-maglev train interaction and basic material to design bridges for maglev trains travelling at high-speed. Depending on the major factors affecting the dynamic effects, the scope of this study was restricted to the relationship between dynamic responses. A concrete box girder was chosen as a bridge model and injured train and rail types in domestic production were selected as the moving train load and guideway analysis model, respectively. From the analysis results, the natural frequency of a bridge for a maglev train, which has a deflection limit L/2000, was higher than those of bridges for general trains. The dynamic responses of the girder of the bridge for a maglev train showed a substantial increase in proportion to the velocities of the moving train like other general bridge cases. Maximum dynamic response of the girder is shown at a moving velocity of 240km/h and increased with increasing moving velocity of train. These results can be used to design a bridge for maglev propulsion trains and provide the basic data to confirm the validity and verification of the design code.

• Journal of the Korean Society for Railway
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• v.13 no.1
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• pp.1-8
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• 2010

In domestic developing magnetically levitated (Maglev) vehicle, bogie frames install electromagnets which provide the vehicles to run with levitation and guidance forces; moreover, the linear motors used for traction are integrated into the same mechanical structure. This paper presents the process which predicts the evaluation of life cycle for bogie frame on various running conditions. Durability analysis considering vibration effect is simulated by using random loads resulted from dynamic simulation which takes into account the irregularities of guide rail. And it supports additional weak points which were not examined in static analysis.