• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2003년도 추계학술대회 논문집(III)
• /
• pp.114-119
• /
• 2003

Passengers are much interested in ineroir noise caused speed-up and mass reduction of railway vehicles. Generally, the major noise source for passenger cars are rolling noise and aerodynamic noise. The purpose of this paper is to evaluate the noise level and to analyze the noise sources for domestic and KTX trains. We also measured the interior noise and the rolling noise for passenger cars. In result, the noise level is below 65dBA for Seamaeul coachs, and below 66dBA for KTX coachs.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 추계학술대회 논문집
• /
• pp.170-175
• /
• 2005

In this study, experimental and theoretical methods were applied to understand brake squeal noise VVVF rolling stock on tracks. Trailer cars needed to payed a particular attention, because they were the major source of brake noise. VVVF rolling stocks for lines no 1 of the subway system in Seoul were used for experimental analyses. In order to study brake squeal noise, a dynamometer test at the S&T Brake, Co., which was a manufacturer of brake pads had performed. For measuring vibration and noise, vibration tests of brake parts (brake lining, brake lining head, back plates, etc.) at the SNUT were executed. Also, vibration tests of disc assembly and lining block at the heavy maintenance shop of the Gunja depot were performed. The modal analyses by using an ANSYS which was one of the CAE commercial program were simulated to know the relationship to the mechanism of brake noise. On the based of the tests and the simulations it was found that specific frequencies of the brake parts affected squeal noise, and improvements for reducing squeal noise were proposed.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 1999년도 춘계학술대회 논문집
• /
• pp.200-207
• /
• 1999

The purpose of this research is to setup the design procedure of low noise rolling stocks. Noise sources are identified at a field test, and the contribution of noise sources to each part of car interior is ensured by sound intensity measurement technique. Added material to each section of the carbody makes it possible to identify absorption or reflection performance of each part to the anterior random noise. Such experimental tests to the exterior noise intruding through the floor represent that the best countermeasure on the floor is to implement reflecting material which can properly interfere noise. Design procedure of low noise rolling stocks is set through several experiments.

• 한국소음진동공학회논문집
• /
• 제17권11호
• /
• pp.1037-1042
• /
• 2007

KTX trains show a high interior noise level in tunnel with concreted track at 300 km/h. Generally, the concreted track has higher sound emissions compared with ballasted track due to the reduced absorption and the major sources of interior noise for KTX are known as the aerodynamic noise and rolling noise. Therefore, It is necessary to find out noise source and noise components to affect interior noise in tunnel with concreted track. In this study, we measure the noise and vibration inside KTX in tunnel in order to find the cause of the interior noise of KTX. The analysis results show that the interior noise of KTX in tunnel with concreted track is increased sharply by a low frequency below 80 Hz. We know that the low frequency noise inside KTX in tunnel with concreted track is generated at the natural frequency of carbody by aerodynamic noise outside gangway and rolling noise. In order to reduce the noise level at 80 Hz, modification of mud-flap length between carbodys is suggested and the effect of noise reduction is examined in tunnel with concreted track.

• 한국철도학회논문집
• /
• 제16권2호
• /
• pp.85-92
• /
• 2013

철도 전동 소음은 철도에서 발생하는 대표적인 소음으로서 차륜과 레일의 음향 조도에 의해 유기된다. 철도 전동 소음의 주요 소음원으로는 침목, 레일 그리고 차륜을 들 수 있다. 따라서 철도의 전동 소음을 해석하기 위해서는 차륜의 진동 특성과 함께 궤도의 진동을 해석하고 그 특성을 이해하는 작업이 수행되어야 한다. 본 논문에서는 전동 소음의 관점에서 레일의 진동을 해석하기 위한 이론적 궤도 모델링에 대해 기술하고, 국내의 대표적인 세 가지 철도 궤도에 대해 진동 해석을 수행하였다. 해석에 사용한 궤도로는 기존선 자갈 도상 궤도, KTX 자갈 도상 궤도, KTX 콘크리트 궤도를 선정하였으며, 각 궤도 별로 레일을 따라 진행하는 파동의 전파 특성을 해석하고 그 결과를 비교하였다. 해석 시 궤도는 이산 지지를 가진 Timoshenko 보로 모델링하였으며, 레일의 평균 진동 속도를 이용해 세 궤도 레일의 방사 소음 특성을 간접 비교하였다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2003년도 추계학술대회 논문집(III)
• /
• pp.628-633
• /
• 2003

Recently, the electronic circuit with microprocessor based control system instead of conventional analog circuit is widely used for rolling stock, and also these circuits are widely adopted for train control and monitoring in modem rapid transit system. Noise, distortion and attenuation are always present in electronic equipments and strictly limit performance. The purpose of this paper is to propose noise reduction technology for electronic equipments in rolling stock.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문집
• /
• pp.323-327
• /
• 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. It is shown that the radiation characteristic of the rolling noise is dipole type. The noise generated by the power unit is radiated as the cosine type. The noise level at an observer is increased in the direction of motion and reduced in the direction opposite to the motion with increasing of the train speed. The calculation results including the moving effect of the noise source at 300km/h show in good agreement.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 춘계학술대회논문집
• /
• pp.542-548
• /
• 2003

This paper describes an overall Noise Assurance Plan(NAP) in the project for developing a new rolling stock. In this paper, the procedure for implementing noise control activities for each development stage on the basis of the NAP is also described. The NAP was developed by KITECH(Korea Institute of Industrial Technology) and ODS(${\Phi}$degaard ＆ Danneskiold-Samsoe in DENMARK). Generally, the main objective of NAP is that noise assurance plan applies to the establishment of organization and personnel's roles and responsibilities, set-up of overall procedure and internal audit program. Here, a few comments are made to the deviations of the actual procedure(G7 Project) relative to the suggested NAP presented. The major difference between the suggested NAP and the actual procedure was the late involvement of the noise consultant resulting in suggestions for design improvements could not be implemented due to the advanced stage of the design. Similarly, the important task of preparing sub-supplier specifications was performed. The proposed NAP will be an efficient tool for noise management in the R＆D project for new rolling stock. Specially, in case that several companies and institutes are involoved in the R＆D team

• International Journal of Railway
• /
• 제4권2호
• /
• pp.42-49
• /
• 2011

Today, rolling stock has become a fast and convenient mode of transportation and has witnessed increased demand. But the speed improvement has resulted in increased aerodynamic noise and therefore residential districts near the railroad tracks are exposed to ever increasing noise level. A study on methodologies for measuring and appraising rolling stock's environmental noise has therefore become an important area of endeavor. In the case of the environmental noise, there are no changes in tone so prediction can be made by reducing areas around the railway. The present study explores estimation of the noise around the railway using scale model, and the source of the noise has been investigated as well. The scale model of rolling stock will have to be able to measure high frequency noise and it is required to be generated in a short amount of time. Since popping a balloon or firing a gun fits this requirement the present study analyzed the characteristics of these two different noise sources. Measurement was made in a large vacant lot and the reflection due to the ground was also examined. The method proposed here can be used in the future for predicting the environmental noise of railway vehicles.

• 한국철도학회논문집
• /
• 제14권3호
• /
• pp.211-215
• /
• 2011

일반적으로 음향파워는 소음원으로부터 방사되는 소음의 예측 및 평가를 위한 가장 중요한 요소 중에 하나이다. 그러나 철도차량 주행 시 이 음향파워를 직접 측정하는 것은 불가능하기 때문에 많은 연구자가 소음 레벨을 이용해서 음향파워를 계산하는 간접적인 방법을 개발하였다. 본 연구에서는 철도차량에서 방사되는 음향파워를 전동소음과 동력소음으로 분리하여 추정하는 방법을 제안하였으며, 이 추정방법의 타당성을 검증하였다. 또한 본 연구에서 제안한 방법을 이용하여 현재 국내에서 운행되는 차량(전동차, 무궁화호, KTX)의 음향파워를 계산하여 분석하였다.