• 한국소음진동공학회논문집
• /
• 제23권7호
• /
• pp.605-616
• /
• 2013

An important source of noise from railways is rolling noise caused by wheel and rail vibrations induced by acoustic roughness at the wheel-rail contact. In the present paper, characteristics of rail vibration and radiated sound power from concrete slab tracks for domestic high speed train(KTX) is investigated by means of a numerical method. The waveguide finite element and boundary element are combined and applied for this analysis. The concrete slab track is modelled simply with a rail and rail pad regarding the concrete slab as a rigid ground. The wave types which contribute significantly to the rail vibration and radiated noise are identified in terms of the mobility and decay rates. In addition, the effect of the rail pad stiffness on the radiated power is examined for two different rail pad stiffnesses.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.1010-1015
• /
• 2009

Rail-pad is an important and readily replaceable component of a railway track, as it is the elastic layer between the rail and the sleeper. Characteristics and useful lifetime prediction of rail-pad was very important in design procedure to assure the safety and reliability. In order to investigate the useful lifetime, the accelerate test were carried out. Accelerated test results changes as the threshold are used for assessment of the useful life and time to threshold value were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the acceleration test, several useful lifetime prediction for rail-pads were proposed.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2004년도 추계학술대회 논문집
• /
• pp.516-521
• /
• 2004

TEEE(Thermoplastic ether-ester elastomer) is expected to reduce the noise and vibration from railway because its unique properties such as porosity. in this study, after building TEEE rail pad at established rail, we conducted practical test and vibration test to inquire the field application and endurance of TEEE material. The test results showed that TEEE material was lower vibration than EVA material, therefore, TEEE material was effective from a vibration reduction point of view.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2002년도 추계학술대회 논문집(I)
• /
• pp.654-659
• /
• 2002

Continuous Welded rail(C.W.R.) tracks has many advantages over the conventional jointed rail track. Due to the elimination of rail joints for thermal expantion, however it many cause the track to be suddenly bucklled by thermal loads. The present study investigates the influences of Pad-fastner on the Thermal buckling behavior of C.W.R. Parametric studies are performed to evaluate the effects of the individual parameters on the upper and lower critical bucklig temperature.

• Elastomers and Composites
• /
• 제53권4호
• /
• pp.220-225
• /
• 2018

Resilient pads play a major role in reducing the impact of loads on a rail in a rail-fastening system, which is essentially used for a concrete track. Although a compression set test is commonly used to measure the durability of a resilient pad, the static spring constant is often observed to be different from the fatigue test. In this study, a modified compression set test method was proposed to monitor the variations in the compression set and static spring constant of a resilient pad with respect to temperature and time. In addition, the life of the resilient pad was predicted by performing an acceleration test based on the Arrhenius equation.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2005년도 추계학술대회 논문집
• /
• pp.247-252
• /
• 2005

쐐기형 레일클램프는 작은 초기 압착력으로 레일을 압착한 후 풍속이 증가함에 따라 쐐기작용에 의해 압착력이 증가하여 레일을 강하게 압착하는 구조를 가지고 있다. 쐐기형 레일클램프를 설계하기 위해서는 쐐기작용을 위한 적정 쐐기각과 초기압착력 발휘를 위한 적정 Locker의 물림각을 결정해야 한다. 적정 쐐기각에 관한 연구는 이미 수행되었으며, 본 연구에서는 Locker의 적정 물림각을 설정하기 위하여 이전 연구를 바탕으로 $10^{\circ}$의 쐐기각을 갖는 레일클램프에서 Locker의 물림각과 Jaw pad의 압착력 사이의 상관관계를 실험적 분석을 통해 살펴보았다. 레일클램프의 초기 압착력은 Locker의 물림각에 의해 결정되므로 3, 4, 5, $6^{\circ}$의 4가지 Locker의 물림각에 따른 Locker의 물림력을 압력게이지를 이용하여 측정한 후 Jaw pad의 압착력을 산출하여 유한요소해석결과와 비교하였다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.91-98
• /
• 2009

For maintaining railroad, accumulated passing tonnage is a determinant factor of appropriate rail replacement time. Recently, Seoul Metro's rail maintaining system and technology is being improved from previous years, which increasing a standard of rail replacement. Thus, this brings importance of estimating and managing for accumulated passing tonnage. In case of light weighted train such as subway, current method of calculating accumulated passing tonnage has defaults of misrepresenting accumulated passing tonnage data. Because current method is based on the weight of passengers and train., and operation data. In addition, currently there is no mechanical and electronic system that could represent and support the accurate data between heavy and non-heavy traffic area, and accumulated passing tonnage is calculated inaccurately by estimating average value each line. The current method of calculating accumulated passing tonnage misleads to unpredictable data that represent inappropriate rail replacement period, which leads to under or over analyzed replacement period. If accumulated passing tonnage is over estimated, rail replacement leads to waste of budget. Hence, it is necessary to construct reliable actual measurement system to manage rail's life safely and efficiently, and in this study the accumulated passing tonnage measurement device is installed with using rail pad of optical fiber sensors and its effect is analyzed.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2007년도 추계학술대회 논문집
• /
• pp.432-441
• /
• 2007

Any track system needs major changes of its components during its life. The most economical solution is, if possible, to make all components reach their life limit during the major track rehabilitation operation. Usually, the rail does a role as the driving component for the objective: its life-time is equivalent to around 500 million tons of traffic on high speed lines. On the KTX line with 110 trains per day, this would correspond to around 16 years, which is probably too long for the elastic pads of a concrete slab track. The most economical solution should be to change them at an intermediate step of 8 years, without changing the rail, and then to change both the rail and elastic pad at 16 years intervals (some rail changes on the South East TGV line in France began 15 years after service opening at 260 km/h, but recent rails have better characteristics).

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집A
• /
• pp.407-412
• /
• 2000

In this study, a research for process design in bending of structural frame of AA6061-T6 with rubber pad was conducted. In this process, the conventional lower die made of metal is replaced with a polyurethane pad, resulting in high flexibility during bending. Vulcanized polyurethane rubber with shore A hardness of 60 was used for the pad. Experiments on a newly developed bending machine were carried out by controlling the stroke of the roller and horizontal movement of roller pad lower die. From this, the relation between roller path and geometry of the materials bent was obtained for the process design of producing roof rail part of a passenger car and the experimental result was compared with the target profile. For more accurate process design, it is required to control the roller path interactively. Based on the experience in developing the prototype bending machine, it is construed that a fully automated bending system with rubber pad to produce various light-weight components for automotive body frames can be successfully developed.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2001년도 춘계학술대회 논문집
• /
• pp.369-374
• /
• 2001

It was estimated that the anti-vibration measures at the source location of railroad are the most active and effective ones. Among CWR(Continuously Welded Rail), elastic rail fastener, floating slab, ballast mat, under sleeper pad, etc. like these various kinds of measures in the source, under sleeper pad as an anti-vibration measure was constructed at the railroad track supporting structures in the Jeon-la Line. In this study, through the field measurement of vibration at the railroad track supporting structures and nearby the ground, the vibration reduction effect of under sleeper pad were evaluated by insertion loss. As a result, vibration reduction effects were 5.0∼12.5㏈ on the concrete slab of the bridge, 3.9∼7.5㏈ on the ground nearby the bridge respectively.