• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.883-888
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• 2004

One of commercial rapid transits produces peculiar booming sound when passing through the slab-track tunnel. In order to analyze that tympanic membrane-pressing noise systematically, typical source-transfer path-response analysis was carried out. Considering the octave band of booming noise, work scope was confined to structure-borne noise analysis, especially the dynamic behaviour of railway tracks. Experimental modal analysis of railway tracks, composed of rail, rubber pad, sleeper, ballast, and ground were performed. The results shows that transversal bending modes of the rail are suspicious for the cause of the low band booming noise. Finite element analysis are made use of to match preceding experimental results, and plausible dynamic properties of track components are produced.

• International Journal of Railway
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• v.6 no.3
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• pp.95-106
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• 2013

Earthborne vibrations are induced by construction operation such as pile driving, roadbed compaction, and blasting and also by transit activities such as truck and trains. The earthborne vibration creates the stress waves traveling outward from the source and can structurally damage nearby buildings and structures in the forms of direct damage to structure and damage due to dynamic settlement. The wave propagation characteristics depends on impact or vibration energy, distance from the source, and soil characteristics. The aim of this paper is to provide a comprehensive review on the mechanistic of earthborne vibration and the current practice of vibration control and mitigation measures. The paper describes the state of knowledge in the areas of: (1) mechanics of earthborne vibration, (2) damage mechanism by earthborne vibration, (3) calculation, prediction of ground vibration, (4) the criteria of vibration limits, (5) vibration mitigation measures and their performance, and (6) the current practice of vibration control and mitigation measures.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.7
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• pp.470-480
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• 2015

As the railway noise guideline of the Ministry of Environment after 2017 is strictly enforced, the noise level at stationary condition of urban railway is demanding the reduction about 2 dB(A). And the noise level at running condition is reduced by 6 dB(A) at 80 km/h. Therefore, the devices that causes noise shall arrange for the improvement plan of noise reduction for each device. In this paper, we carried out a technical review of the driving gear used to drive the vehicle from a variety of noise-induced equipment of a urban railway. Analyze the causes of the current noise levels and noise cause about the driving gear used in current urban railway and this study analyzes the noise level and noise cause the drive gear being used in the current urban railway. Finally, in this paper proposes a scheme for reducing the noise that can be designed to reduce the noise with considering the noise cause analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.843-848
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• 2011

Planning and construction of railway for high speed trains up to 400 km/h are recently driven in Korea. High speed train is one of the environment-friendly fastest mass transportation means but its noise generated by rolling, traction and aerodynamic mechanism can cause public complaints of residents nearby railways. To cost-effectively prevent the troublesome noise in a railway planning stage, the rational railway noise prediction method considering the characteristics of trains as well as railway structures should be required but it is difficult to find authentic methods for Korean high speed trains such as KTX and KTX-II. In this study, we propose a framework of our own railway noise prediction model emitted by Korean high speed trains over 250 km/h based on the recent research results carried out in EU countries. The model considers railway sound power level using several point sources distributed in heights as well as tracks, whose detail speed- and frequency-dependent emission characteristics of Korean high speed trains should be determined in near future by measurement or numerical analysis. The attenuation during propagation outdoors is calculated by the well-known ISO 9613-2 and auxiliary methods to consider undulated terrain and wind effect.

• Structural Engineering and Mechanics
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• v.75 no.4
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• pp.507-518
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• 2020

With the rapid development of rail transit, rail transit noise needs to be paid more and more attention. In order to accurately and effectively analyze the characteristics of low-frequency noise, a prediction model of vibration of box girder was established based on the hybrid FE-SEA method. When the train speed is 140 km/h, 200 km/h and 250 km/h, the vibration and noise of the box girder induced by the vertical wheel-rail interaction in the frequency range of 20-500 Hz are analyzed. Detailed analysis of the energy level, sound pressure contribution, modal analysis and vibration loss power of each slab at the operating speed of 140 km /h. The results show that: (1) When the train runs at a speed of 140km/h, the roof contributes more to the sound pressure at the far sound field point. Analyzing the frequency range from 20 to 500 Hz: The top plate plays a very important role in controlling sound pressure, contributing up to 70% of the sound pressure at peak frequencies. (2) When the train is traveling at various speeds, the maximum amplitude of structural vibration and noise generated by the viaduct occurs at 50 Hz. The vibration acceleration of the box beam at the far field point and near field point is mainly concentrated in the frequency range of 31.5-100 Hz, which is consistent with the dominant frequency band of wheel-rail force. Therefore, the main frequency of reducing the vibration and noise of the box beam is 31.5-100 Hz. (3) The vibration energy level and sound pressure level of the box bridge at different speeds are basically the same. The laws of vibration energy and sound pressure follow the rules below: web

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.53-59
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• 2019

To reduce the vibrations and shocks during the cargo transportation of high value-added goods, the vibration history was measured on the truck transportation section (Asan-Uiwang) and the freight train transportation section (Uiwang-Pusan). The internal vibrations of the container were obtained by attaching acceleration sensors in three axis directions (longitudinal, lateral. and vertical directions) on the front and rear bogies. The rail vibration profile (0.29Grms) proposed in ASTM D-4169 was approximately 50% higher than the truck vibration profile (0.54Grms). The overall vibration was 16% and 33 % lower in the longitudinal and transverse directions, respectively, compared to the ASTM truck transport vibration profile. On the other hand, the vertical vibration measurement history partially exceeded the ASTM truck transport vibration profile over the range, 4 - 15Hz, and over 60Hz. The vibration measurement history of the cargo train was similar to that of the road. The longitudinal and lateral vibration history was lower than the ASTM D-4169 rail vibration profile, while the vertical history was over 30Hz.

• Journal of the Korean Society for Railway
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• v.16 no.4
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• pp.246-252
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• 2013

The vibration characteristics of railway vehicles are very complex because they are not only dependent on vehicle and track conditions but also on operating conditions. Vibration can cause the failure of rolling stock equipment. To verify that the quality of rolling stock equipment is acceptable, it should be able to withstand vibration tests of reasonable magnitude and duration. There are many standards for vibration and shock tests of equipment in Korea. In this paper, we have reviewed and compared the standards (KS R 9144, R 9146 and IEC 61373) for vibration and shock tests.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3557-3566
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• 2015

In the case of elevated railway station in which railway is connected with superstructure of station, vibration and noise level is relatively higher than those of general structure type station due to structural characteristic which transmits vibration directly. Therefore, characteristic understanding of structural vibration and accompanying structure cause noise and establishment of reduction plan through the results are in need. Test and analysis are performed in this research to consider correlativity between structural vibration and accompanying structure cause noise when external forces are applied on standard slab and floating slab which is able to isolate vibration. By producing and loading on standard and floating slab, vibration and noise response are measured while simulation using numerical analysis, finite element method and SEA method is performed. The results about structural dynamic behavior of slab, correlativity between structural vibration and noise, reduction performance of floating slab is deduced through the analysis of tests.

• Structural Engineering and Mechanics
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• v.77 no.5
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• pp.601-612
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• 2021

To study the vibration characteristics of a high-speed railway continuous girder bridge-track coupling system (HSRCBT), a coupling vibration analysis model of an m-span continuous girder bridge-subgrade-track system with n-span approach bridge was established. The model was based on the energy and its variational method, where both the interlaminar slip and shear deformation effects were considered. In addition, the free vibration equations and natural boundary conditions of the HSRCBT were derived. Further, according to the coordination principle of deformation and mechanics, an analytical method for calculating the natural vibration frequencies of the HSRCBT was obtained. Three typical bridge-subgrade-track coupling systems of high-speed railway were taken and the results of finite element analysis were compared to those of the analytical method. The errors between the simulation results and calculated values of the analytical method were less than 3%, thus verifying the analytical method proposed in this paper. Finally, the analytical method was used to investigate the influence of the number of the approach bridge spans and the interlaminar stiffness on the natural vibration characteristics of the HSRCBT based on the degree of sensitivity. The results suggest the approach bridges have a critical number of spans and in general, the precision requirements of the analysis could be met by using 6-span approach bridges. The interlaminar vertical compressive stiffness has very little influence on the low-order natural vibration frequency of HSRCBT, but does have a significant influence on higher-order natural vibration frequency. As the interlaminar vertical compressive stiffness increases, the degree of sensitivity to interlaminar stiffness of each of the HSRCBT natural vibration characteristics decrease and gradually approach zero.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2263-2268
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• 2011

THE VIBRATION MODE OF RAILWAY VEHICLE IS DIFFICULT TO FIND OUT THE CHARACTERISTICS OF MOTION DURING THE OPERATION ON THE TRACK BECAUSE THESE HAPPEN TO INDEPENDENCE OR DUPLICATION MOTION CAUSED BY VEHICLE, WHEEL/RAIL INTERACTION, TRACK IRREGULARITY AND FAILURE OF THE SUSPENSION & POWER TRANSMISSION DEVICE ETC. IT IS NAMED AN ABNORMAL VIBRATION THAT THE VIBRATION, WHICH WAS PASSED THE PRIMARY AND SECONDARY SUSPENSION, IS AFFECTED TO THE PASSENGER OR DRIVER WITHOUT DAMPING. THIS PAPER DESCRIBES AN EXPERIENCE EVALUATION TO FIND OUT THE CAUSE OF AN ABNORMAL VIBRATION WHICH WAS HAPPEN AT THE CAB OF POWER CAR IN KTX-SANCHEON TRAINSET WHEN ON RUNNING AT HIGH SPEED ZONE.