• Title, Summary, Keyword: 레일 음향조도

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Effect of Design variables of Rail Surface Measuring Device on Acoustic Roughness and Spectral Analysis (레일표면 측정장치의 설계변수가 음향조도 스펙트럼 분석에 미치는 영향)

  • Jeong, Wootae;Jeon, Seungwoo;Jeong, Dahae;Choi, Han Shin
    • Journal of the Korean Society for Railway
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    • v.20 no.4
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    • pp.440-447
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    • 2017
  • Spectrum level for the acoustic roughness of wheels and rail surface should be periodically maintained under the limitation of ISO to reduce rolling noise of railway vehicles. Thus, in maintaining railway track, displacement sensor-based measuring devices are broadly used to measure the surface roughness and to perform spectral analysis. However, these measuring devices cause unexpected measuring errors since the displacement sensors are fixed at moving platforms and the main frame produces pitching motion during measurement. To increase the accuracy of the measured values, this paper has investigated the effects of design variables such as wheel base, additional wheels, and elastic deformation of wheels on the surface roughness and acoustic roughness spectrum.

Measuring Technique For Acoustic Roughness of Rail Surface With Homogeneous Displacement Sensors (동일 변위센서를 사용한 레일표면 음향조도의 측정방법)

  • Jeong, Wootae;Jang, Seungho;Kho, Hyo-In
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.11
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    • pp.7941-7948
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    • 2015
  • Rolling noises during train operation are caused by vibration excited from irregularities of surface roughness between wheel and rail. Therefore, a proper measurement and analysis techniques of acoustic roughness between wheel and rail surface are required for transmission, prediction, and analysis of the train rolling noise. However, since current measuring devices and methods use trolley-based manual handling devices, the measurements induce unstable measuring speed and vibrational interface that increases errors and disturbances. In this paper, a new automatic rail surface exploring platform with a speed controller has been developed for improving measurement accuracy and reducing inconsistency of measurements. In addition, we propose a data integration method of the rail surface roughness with multiple homogeneous displacement sensors and verified the accuracy of the integrated data through standard test-bed railway track investigation.

Study on the Rolling Noise Model Using an Analysis of Wheel and Rail Vibration Characteristics (철도 차륜 및 레일 진동 특성 해석을 통한 전동 소음 모델 연구)

  • Jang, Seungho;Ryue, Jungsoo
    • Journal of the Korean Society for Railway
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    • v.16 no.3
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    • pp.175-182
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    • 2013
  • Rolling noise is an important source of noise from railways; it is caused by wheel and rail vibrations induced by acoustic roughness at the wheel/rail contact. To reduce rolling noise, it is necessary to have a reliable prediction model that can be used to investigate the effects of various parameters related to the rolling noise. This paper deals with modeling rolling noise from wheel and rail vibrations. In this study, the track is modeled as a discretely supported beam by regarding concrete slab tracks, and the wheel vibration is simulated by using the finite element method. The vertical and lateral wheel/rail contact forces are modeled using the linearized Hertzian contact theory, and then the vibration responses of the wheel and rail are calculated to predict the radiated noise. To validate the proposed model, a field measurement was carried out for a test vehicle. It was found that the predicted result agrees well with the measured one, showing similar behavior in the frequency range between 200 and 4000 Hz where the rolling noise is prominent.

Effect of Design Factors on the Vibration of the Steering Wheel of a Passenger Car (승용차 조향계 진동에 미치는 제인자)

  • 박철희;홍성철;송상기
    • The Journal of the Acoustical Society of Korea
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    • v.10 no.5
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    • pp.37-45
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    • 1991
  • 일반 소형 승용차의 고속 주행시 발생하는 진동 중 조향휠의 원주방향의 진동인 shimmy 현상을 연구하였다. Shimmy 현상은 쾌적한 차량 설계단계에서 예측할 수 있고 그 원인을 추정할 수 있도록 조 향계의 모델링 및 이론해석을 하였으며 실험결과치와의 비교검토를 통하여 모델링에 대한 타당성을 검 증하였다. 검증된 모델링을 이용하여 조향계를 구성하는 각 부재의 감쇠, 강성, 타이어의 트레일 및 stabilizer bar 의 강성등의 변화가 조향휠 진동에 미치는 영향을 고찰하였다. 특히 shimmy 현상이 타이 어의 편마모등에 의한 unbalance mass에 얼마나 민감한가를 실험 및 이론적인 해석을 통하여 고찰하였다.

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