• Wind and Structures
• /
• 제20권2호
• /
• pp.143-168
• /
• 2015

A numerical model for analyzing air-train-track interaction is proposed to investigate the dynamic behavior of a high-speed train running on a track in crosswinds. The model is composed of a train-track interaction model and a train-air interaction model. The train-track interaction model is built on the basis of the vehicle-track coupled dynamics theory. The train-air interaction model is developed based on the train aerodynamics, in which the Arbitrary Lagrangian-Eulerian (ALE) method is employed to deal with the dynamic boundary between the train and the air. Based on the air-train-track model, characteristics of flow structure around a high-speed train are described and the dynamic behavior of the high-speed train running on track in crosswinds is investigated. Results show that the dynamic indices of the head car are larger than those of other cars in crosswinds. From the viewpoint of dynamic safety evaluation, the running safety of the train in crosswinds is basically controlled by the head car. Compared with the generally used assessment indices of running safety such as the derailment coefficient and the wheel-load reduction ratio, the overturning coefficient will overestimate the running safety of a train on a track under crosswind condition. It is suggested to use the wheel-load reduction ratio and the lateral wheel-rail force as the dominant safety assessment indices when high-speed trains run in crosswinds.

• 대한교통학회지
• /
• 제9권2호
• /
• pp.75-86
• /
• 1991

A conventional track structure system of rails ties ballast subballast and subgrade. An adequate engineering analysis require consideration of all major components of track system. This paper briefly reviews existing methods of track analysis and presents a new model based of the examination of the Tallbot Model. The new model has been validated by comparision with settlements from other model.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.2400-2404
• /
• 2011

Power spectral density (PSD) model of irregularities for the maglev test track is presented. Track irregularities (gauge, cant, twist and vertical) were calculated from the survey data of sleepers on the test track. PSD model was constructed from the estimated PSDs of each track irregularities. Versine (gauge, cant, twist, vertical and lateral) of the track is obtained and their PSDs were estimated, too. Presented PSD model can be used for the analysis of levitation stability and ride quality of the maglev system.

• Structural Engineering and Mechanics
• /
• 제74권5호
• /
• pp.589-600
• /
• 2020

The bonding interface of the concrete slab track and cement-asphalt mortar layer plays an important role in transferring load and restraining the track slab's deformation for slab track structures without concrete bollards in high-speed railway. However, the interfacial bond-slip behavior is seldom considered in the structural analysis; no credible constitutive model has been presented until now. Elaborating the field tests of concrete to cement-asphalt mortar interface subjected to longitudinal and transverse shear loads, this paper revealed its bond capacity and failure characteristics. Interfacial fractures all happen on the contact surface of the concrete track slab and mortar-layer in the experiments. Aiming at this failure mechanism, an interfacial mechanical model that employed the bilinear local bond-slip law was established. Then, the interfacial shear stresses of different loading stages and the load-displacement response were derived. By ensuring that the theoretical load-displacement curve is consistent with the experiment result, an interfacial bond-slip constitutive model including its the corresponding parameters was proposed in this paper. Additionally, a finite element model was used to validate this constitutive model further. The constitutive model presented in this paper can be used to describe the real interfacial bonding effect of slab track structures with similar materials under shear loads.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.66-72
• /
• 2009

In order to forecast the progress of the track irregularity, we should observe the long-term track quality and divide a track into some separated divisions which have homogeneous property. For this, we define the division of track which has homogeneous property as a 'Segment' and manage the 'TQI(Track Quality Index)' using track induction data based on each segment. In this study, we introduce some methods of estimating track quality and figure out the TQIs of sample section using new FRA TQI method. In addition, we conducted a basic study of the forecasting model for the progress of track irregularity by analyzing track maintenance data.

• Communications for Statistical Applications and Methods
• /
• 제22권3호
• /
• pp.241-253
• /
• 2015

In this paper we predict the track of typhoons using a Bayesian principal component regression model based on wind field data. Data is obtained at each time point and we applied the Bayesian principal component regression model to conduct the track prediction based on the time point. Based on regression model, we applied to variable selection prior and two kinds of prior distribution; normal and Laplace distribution. We show prediction results based on Bayesian Model Averaging (BMA) estimator and Median Probability Model (MPM) estimator. We analysis 8 typhoons in 2006 using data obtained from previous 6 years (2000-2005). We compare our prediction results with a moving-nest typhoon model (MTM) proposed by the Korea Meteorological Administration. We posit that is possible to predict the track of a typhoon accurately using only a statistical model and without a dynamical model.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.55-65
• /
• 2009

This study is objected by analyzing whether it is applied to the analysis model considering the track stiffness or not when the railway bridge is designed or reviewed for the dynamic stability. It is performed that the analysis model is verified by comparing the field test result with the analysis result. Also, The dynamic response of railway bridge through the existing analysis model is compared with the analysis model considered the track stiffness. In addition, it is performed by analyzing the model considering the stiffness of concrete track. Therefore, this study is suggested that the design of railway bridge apply to the existing analysis model considering the mass of track and the dynamic stability review of railway bridge apply to it considered the stiffness & mass of track. Also, it is suggested that the stiffness of concrete slab on the bridge must consider when it is designed or checked over the dynamic stability.

• 한국지반신소재학회논문집
• /
• 제9권3호
• /
• pp.1-8
• /
• 2010

국내에 적용하고 있는 궤도시스템은 크게 자갈궤도와 콘크리트궤도로 구분할 수 있다. 본 논문에서는 콘크리트궤도와 자갈궤도의 노반 거동현상을 실험적으로 비교하였다. 실 대형 실험결과 하중 분산은 자갈궤도의 경우 연성포장구조, 콘크리트궤도는 강성포장구조의 형태로 하중이 분산되었으며 하중배분율은 약 30%:20%:15%로 자갈궤도보다 폭 넓게 분산되었다. 열차하중에 대한 노반에서 발생된 토압은 약 30kPa 이내로 기존 실차주행시험결과와 유사한 결과이며 자갈궤도에 비해 약 4배 정도 작게 발생하였다. 또한 반복하중에 대한 콘크리트궤도의 지중입자속도는 약 0.3cm/sec 이내로 자갈궤도보다 8배 정도 작게 측정되었다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2007년도 추계학술대회 논문집
• /
• pp.1077-1092
• /
• 2007

The structural analysis model for estimate of load carrying capacity of railway bridge on service line is important to determine safety of bridges in service, we need to take response of bridge exactly, applying analysis model similar to the real railway bridge most. Track structure which is to distribute loads and decrease vibrations occurred from running train is constructed on the railway bridges. And it is important factor which should be considered to understand exact dynamic and static responses of bridge. But track structure is currently classified as a none structural members in the structural analysis model for estimating load carrying capacity of railway bridge and not considered in analysis model. That's the reason it is difficult to understand exact behavior of bridges. Therefore, the major objective of this study is to develop an analytical track-bridge model which is similar to real railway bridges considering track structure for safety assessment of railway bridge on service line to be effectively done.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 추계학술대회 논문집
• /
• pp.261-264
• /
• 1997

In case of high speed and high mobility multibody tracked vehicle, it is hard to develop the realtime simulation model for track tension control because of the hundreds of highly nonlinear equations. In order to design more trustworthy realtime simulator for track tension control, it is necessary to use off-line tracked vehicle model. In this study, a step by step procedure is presented to develop realtime simulation model based on off-line tracked vehicle model. Simulation results show that modified off-line multibody tracked vehicle model can be used for real time simulation to control the track tension.