• Title, Summary, Keyword: Interior noise

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Comparison of Interior Noise for High Speed Trains in Korea (국내 고속철도 차량의 실내소음 특성 비교)

  • Kim, Jae-Chul;Lee, Chan-Woo;Jeong, Soon-Chul
    • Proceedings of the KSR Conference
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    • pp.90-94
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    • 2007
  • There are the high-speed train of two types in Korea, KTX and KHST(Korean High Speed Train). The characteristics of interior noise appear differently because the car bodies of the trains are designed with the different materials. In this study, we measure the interior noise for KTX and KHST. The experimental results show that the interior noise of KTX is equal to KHST in open territory and tunnel and interior noise in tunnel with concreted track increase about $3{\sim}4dB(A)$ compared to tunnel with ballasted track. We also know that interior noise level of KHST is higher then KTX in range of high frequency (above 630Hz).

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A Study of Response Characteristics for the Interior Impulse Noise based on Interpreted Models (해석 모델 기반의 실내 충격소음 응답특성에 관한 연구)

  • Song, Kee-Hyeok;Chung, Sung-Hak
    • Journal of the Korean Society of Safety
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    • v.29 no.5
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    • pp.22-28
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    • 2014
  • This study is compare to model-based analysis and experimental data of the response characteristic of interior impulse noise. Interior impulse noise and the pressure response characteristics of the building structure on its analysis are presented the impulse pressure acting on the rear wall 90 N-sec. The force acting on the wall $CFD^{{+}{+}}$ which are compared measurement and simulation analysis. Results of simulation and measurement data were shown. In this study, a high dimension of the degree of virtual space in the numerical space of the lesser degree in order to calculate folding method was applied. The results of this study contribute safety evaluation and model development for the interior impulse noise that affects the basic data for the interior impulse noise model validate for the physical quantity prediction.

A Study Interior Noise Reduction of a Maglev Train at Low Speed (저속 주행시 자기부상열차의 실내소음저감에 관한 연구)

  • 김현실;김재승;강현주;김봉기;김상렬
    • 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.

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Simulation on the Reduction of Interior Noise using the Transfer Path Analysis of the Active Engine Mount (엔진마운트의 전달경로해석을 통한 실내소음저감 시뮬레이션)

  • Lee, Choong-Hwi;Kim, Young-Ho;Choy, Hyun-Joon;Won, Jong-Sik
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.166-170
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    • 2008
  • In this study, it proved that transfer path analysis is a proper technique to estimate the interior noise from comparing measured interior noise in case of 3 point supported engine mount system. And the simulation of the vibration isolation for active engine mount using FXLMS algorithm is performed. Also, it verified that reduction of estimated interior noise from transfer path analysis and simulation of the vibration isolation.

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What are measures to reduce interior noise for KTX in tunnel with concrete track? (콘크리트 궤도 터널 주행 시 KTX차량의 실내소음 저감방안은 무엇인가?)

  • Kim J.C.;Koh H.I.;Lee C.W.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.29-30
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    • 2006
  • The interior noise of KTX in tunnel has become an issue since the commercial operating in April 2004. The analysis of the interior noise of KTX in tunnel with concrete track shows sharply increased noise level in the range of 80Hz that is the natural frequency of the KTX carbody. We know that the booming noise inside KTX in tunnel with concrete track is generated by noise outside gangway and rolling noise at the carbody natural frequency. In this Study noise reduction methods are discussed on the basis of the comparison of the KTX and KHST noise characteristics. Alternatively, the effect of the modified mud-flap on the interior noise is introduced.

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Analysis of Interior Noise of High-Speed Train via SEA (고속철도 차량의 실내소음 해석: SEA 응용)

  • Kim, Tae-Min;Kim, Jung-Tae;Kim, Jung-Soo
    • Proceedings of the KSR Conference
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    • pp.447-453
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    • 2009
  • The interior noise of the High Speed Train(HST) is analyzed by applying the statistical energy analysis (SEA) method. The interior of each vehicle is divided lengthwise into nine cavities. Since the rolling noise and aerodynamics noise are expected to be dominant noise sources, they are treated as the noise sources in the model. To further simplify the model, curtains and seats are excluded. The simulation runs involving one-car, three-car and five-car trains are conducted. The maximum predicted noise level is 98.4dB. The results also show that the predicted noise levels are within 0.23% of each other. The results imply that it is not necessary to estimate the interior noise of the train by constructing multiple-car train models. The noise estimate based on just one-car train can be optimal with respect to the computational effort and modeling time.

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A Study on Influence of High Pressure Hose On Automotive Power Steering Interior Noise Using frequency Analysis (유압식 자동차 동력조향장치 실내소음에 고압호스가 미치는 영향의 주파수 분석을 통한 연구)

  • Jeon, S.G.;Shin, J.Y.;Hwang, H.J.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.51-56
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    • 2002
  • High pressure hose having tuning cables, called 'Resonator hose' is frequently used to attenuate pressure ripple generated by the pump for reducing the vehicle interior noise. A number of studies have been conducted on the resonator hose and its analytical models. However, there are few studies which deal with the influence of resonator hose on vehicle interior noise because the most of studies focused on transmission loss of the resonator hose. This paper presents NVH test results of power steering system and frequency analysis results. In the frequency analysis, both the relations between vibration, pressure ripple and vehicle interior noise and also the design parameters of high pressure hose influencing on vehicle interior noise were discussed. The test was done for various high pressure hose specimens in full turn condition.

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Prediction of Interior Noise by Excitation Force of Powertrain Based on Hybrid Transfer Path Analysis (Hybrid TPA를 이용한 파워트레인 구조기인 실내소음 예측)

  • Kim, Sung-Jong;Lee, Sang-Kwon
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.12
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    • pp.117-124
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    • 2008
  • In early design stage, the simulation of interior noise is useful for the enhancement of the noise, vibration and harshness (NVH) performance in a vehicle. The traditional transfer path analysis (TPA) technology cannot simulate the interior noise since it uses the experimental method. In order to solve this problem, in this paper, the hybrid TPA is developed as the novel approach. The hybrid TPA uses the simulated excitation force as the input force, which excites the flexible body of a car at the mount point, while the traditional TPA uses the measured force. This simulated force is obtained by numerical analysis for the FE (finite element) model of a powertrain. The interior noise is predicted by multiplying the simulated force by the vibro-acoustic transfer function (VATF) of the vehicle. The VATF is the acoustic response in the compartment of a car to the input force at the mount point of the powertrain in the flexible car body. The trend of the predicted interior noise based on the hybrid TPA very well corresponds to the measured interior noise, although there is some difference due to not only the experimental error and the simulation error but also the effect of the air-borne path.

Evaluation of Car Interior Noise by Using EEG (뇌파를 이용한 적정 자동차 내부소음의 평가)

  • 김정룡;박창순
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.24 no.65
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    • pp.65-73
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    • 2001
  • In this study, psychophysiological stress was quantitatively evaluated at various car interior noise levels by using Electroencephalogram(EEG). An experiment was performed to investigate the most comfortable range of noise level during simulated driving condition. Twelve healthy volunteers participated in the experiment. They were asked to operate the driving simulator while six levels of interior noise were given, such as 45dB(A), 50dB(A), 55dB(A), 60dB(A), 70dB(A), 80dB(A), and maximal subjective noise level. EEG signals were recorded for 60 seconds in each noise level. The power spectral analysis was performed to analyze EEG signal. At the same time, psychological stress was also measured subjectively by using a magnitude estimation method. The results showed that subjective stress and EEG spectrum indicated a statistically significant difference between noise levels. In particular, high level noise produced an increase in beta power at temporal(T3, T4) areas. It was also found that beta activity was highly correlated with subjective perception of discomfort, and subjects responded to car interior noise as arousing or negative stimuli. Moreover, beta power remained stable above 70dB(A), whereas subjective discomfort continued to increase even above 70dB(A) We concluded that brain waves could provide psychophysiological information of drivers emotional reaction to car interior noise. Thus, EEG parameters could be a new measure to determine optimal noise level in ergonomic workplace design after further verification in various experimental conditions.

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An interior noise analysis of KTX vehicles on various operating conditions (한국형 고속철도 차량의 운행조건에 따른 차내 소음 분석)

  • Choi Sunghoon;Kim Jae-Chul;Lee Chan-Woo;Moon Kyung-Ho
    • Proceedings of the KSR Conference
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    • pp.138-142
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    • 2003
  • The conditions for measurement of the interior noise should meet the international standards. However, due to the limitations in test conditions the possible errors in measurement equipment, reliability of the measurement results has been questioned. Hence, the test procedure for the interior noise measurement of KTX vehicles are reviewed and investigated with the reference of international standards. Furthermore, the acceptable tolerance is inspected through the analysis of the factors that influence the interior noise of the KTX vehicle.

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