Derailment and Dynamic Analysis of Tilting Railway Vehicles Moving Over Irregular Tracks Under Environment Forces

2017 ◽  
Vol 17 (09) ◽  
pp. 1750098 ◽  
Author(s):  
Yung-Chang Cheng ◽  
Chern-Hwa Chen ◽  
Chin-Te Hsu
Keyword(s):  
Degrees Of Freedom ◽  
Creep Model ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Railway Vehicles ◽  
Running Safety ◽  
Car Model ◽  
Vertical Roll ◽  
Rail Irregularities ◽  
Creep Models

Utilizing a nonlinear creep model, the dynamic behavior of tilting railway vehicles moving over curved tracks with rail irregularities and under earthquakes and wind loads is studied. The car model adopted consists of 28 degrees of freedom, capable of simulating the lateral, vertical, roll and yaw motions for the wheelsets, truck frames and car body. The derailment quotient is investigated to analyze the running safety of a tilting railway vehicle using the linear and nonlinear creep models, while considering the rail irregularities and environmental forces for various tilting angles. Generally, the derailment risk of the tilting railway vehicle is higher than that of non-tilting railway vehicle with or without rail irregularities and environmental forces. The derailment quotients calculated by the linear creep model are underestimated for a tilting railway vehicle. In addition, the derailment quotients evaluated for rough rails and under environmental forces are higher than those obtained for smooth rails with no environmental forces. It is confirmed that rail irregularities and each type of environmental forces have decisive effects on derailment quotients. They are compared and ranked according to their significance.

Running Safety and Comfort Analysis of Railway Vehicles Moving on Curved Tracks

2014 ◽  
Vol 14 (04) ◽  
pp. 1450004 ◽  
Author(s):  
Yung-Chang Cheng ◽  
Chin-Te Hsu
Keyword(s):  
Degrees Of Freedom ◽  
Lateral Displacement ◽  
Equations Of Motion ◽  
Creep Model ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Running Safety ◽  
Comfort Index ◽  
Vertical Displacements ◽  
Index Formulas

Using a heuristic linear creep model, this study derives the governing differential equations of motion for the railway vehicle traveling on curved tracks. The railway vehicle is modeled as a car system with 27 degrees-of-freedom (DOFs), taking into account the lateral and vertical displacements, roll and yaw angles of the wheelsets and truck frames, as well as the lateral displacement, roll and yaw angles of the car body. The effects of railway vehicle speeds on the derailment quotients and offload factors related to running safety are evaluated by both the linear and nonlinear creep models for various radii of curved tracks. Using the Sperling and modified Sperling index formulas, the effects of railway vehicle speeds on lateral riding quality and comfort are illustrated for the two models with various radii of curved tracks. Furthermore, the effects of railway vehicle speeds on the lateral Sperling comfort index of the 27-DOF car model are presented and compared for various suspension parameters. Finally, the acceptable region for riding quality and comfort are drawn.

Hunting Stability Analysis of a New High-Speed Railway Vehicle Model Moving on Curved Tracks

2007 ◽  
Author(s):  
Yung-Chang Cheng ◽  
Sen-Yung Lee
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Lateral Displacement ◽  
Creep Model ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Car Body ◽  
Suspension Parameters ◽  
Virtual Boundary ◽  
Hunting Stability

A new dynamic model of railway vehicle moving on curved tracks is proposed. In this new model, the motion of the car body is considered and the motion of the tuck frame is not restricted by a virtual boundary. Based on the heuristic nonlinear creep model, the nonlinear coupled differential equations of the motion of a fourteen degrees of freedom car system, considering the lateral displacement and the yaw angle of the each wheelset, the truck frame and the car body, moving on curved tracks are derived in completeness. To illustrate the accuracy of the analysis, the limiting cases are examined. In addition, the influences of the suspension parameters on the critical hunting speeds evaluated via the linear and the nonlinear creep models respectively are studied. Furthermore, the influences of the suspension parameters on the critical hunting speeds evaluated via the fourteen degrees of freedom car system and the six degrees of freedom truck system, which the motion of the tuck frame is restricted by a virtual boundary, are compared.

Parametric Analysis of Ride Comfort for Tilting Railway Vehicles Running on Irregular Curved Tracks

2016 ◽  
Vol 16 (09) ◽  
pp. 1550056 ◽  
Author(s):  
Yung-Chang Cheng ◽  
Chin-Te Hsu
Keyword(s):  
Ride Comfort ◽  
Lateral Displacement ◽  
Equations Of Motion ◽  
Roll Angle ◽  
Creep Model ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
Nonlinear Creep ◽  
Rail Irregularities ◽  
Yaw Angle

The ride comfort of a tilting railway vehicle moving on curved tracks with rail irregularities is studied. Using the nonlinear creep model and Kalker's linear theory, the governing differential equations of motion for a tilting railway vehicle running on irregular tracks are first derived. The tilting railway vehicle is modeled by a 27 degree-of-freedom (DOF) car system, considering the lateral displacement, vertical displacement, roll angle and yaw angle of both the wheelsets and bogie frames, as well as the lateral displacement, roll angle and yaw angle of the car body. Based on the international standard ISO 2631-1, the effect of vehicle speed on the ride comfort index of the tilting vehicle is investigated for various tilting angles, using both linear and nonlinear creep models, and various radii of curved tracks, as well as for various suspension parameters. Finally, the ride comfort indices computed with rail irregularities are found to be higher than those with no rail irregularities, indicating that the effect of rail irregularities on the ride comfort of a tilting vehicle cannot be disregarded in practice.

DERAILMENT RISK ANALYSIS OF A TILTING RAILWAY VEHICLE MOVING OVER IRREGULAR TRACKS UNDER WIND LOADS

2013 ◽  
Vol 13 (08) ◽  
pp. 1350038 ◽  
Author(s):  
YUNG-CHANG CHENG ◽  
CHENG-HAO HUANG ◽  
CHEN-MING KUO ◽  
CHERN-HWA CHEN
Keyword(s):  
Equations Of Motion ◽  
Wind Loads ◽  
Creep Model ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Lateral Direction ◽  
Bogie Frame ◽  
Car Body ◽  
Tilting Angle ◽  
Rail Irregularities

Based on the nonlinear creep model and Kalker's linear theory, this paper studies the governing differential equations of motion for a tilting railway vehicle moving over irregular curved tracks under wind loads. The tilting vehicle is modeled by a 24-degree-of-freedom (24-DOF) car system, considering the lateral, roll and yaw motions of each wheelset, the lateral, vertical, roll and yaw motions of each bogie frame and the car body. The derailment quotients of the tilting railway vehicle with the wheelsets moving over irregular rails in the lateral direction and the car body acted upon by the wind loads are investigated for various tilting angles. The analysis results show that in general, the derailment quotient of the wheelset increases as the tilting angle of the railway vehicle increases. When the railway vehicle moves at low speeds, the derailment quotient calculated for the case with rail irregularities is greater than that for the case with no rail irregularities. Moreover, the derailment quotient of a wheelset moving over curved tracks of various radii is presented. Finally, the derailment quotient computed for the case under wind loads is greater than that free of wind loads. As a result, the influence of rail irregularities and wind loads on the derailment risk of a tilting vehicle cannot be ignored.

A New Dynamic Model of High-Speed Railway Vehicle Moving on Curved Tracks

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Sen-Yung Lee ◽  
Yung-Chang Cheng
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Lateral Displacement ◽  
Creep Model ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Six Degrees Of Freedom ◽  
Car Body ◽  
Yaw Angle

A new dynamic model of railway vehicle moving on curved tracks is proposed. In the new model, the motion of the car body is considered and the motion of the truck frame is not restricted by a virtual boundary. Based on the heuristic nonlinear creep model, the nonlinear coupled differential equations of the motion of an eight degrees of freedom car system—considering the lateral displacement and the yaw angle of each wheelset, the truck frame, and the half car body—moving on curved tracks are derived completely. To illustrate the accuracy of the analysis, the limiting cases are examined. It is shown that the influence of the gyroscopic moment of the wheelsets on the critical hunting speed is negligible. In addition, the influences of the suspension parameters, including those losing in the six degrees of freedom system, on the critical hunting speeds evaluated via the linear and the nonlinear creep models are studied and compared.

scholarly journals Influence of suspension parameter for derailment analysis of a full railway vehicle model cruising on a curved track

2021 ◽  
Author(s):  
Yamika Patel ◽  
◽  
Vikas Rastogi ◽  
Wolfgang Borutzky ◽  
◽  
...  
Keyword(s):  
High Speed ◽  
Research Work ◽  
Creep Model ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
Nonlinear Creep ◽  
Pitch Motion ◽  
Proposed Model ◽  
Curved Track ◽  
Creep Models

The main intention of this research work is to study the derailment response of high speed railway vehicle (HSRV) cruising on a curved track. In previous research work, lower degree of freedom (DOF) has been considered for the derailment analysis which may not give more accurate results. Hence, a 31 DOF bondgraph model of HSRV has been developed which consist of carbody, two truck frames and two selfsame wheelsets for each truck frame. Vertical, lateral, roll, yaw and pitch motion are considered for carbody and bogie and except pitch motion all the other motion are considered for wheelsets. Non-linearities in terms of heuristic nonlinear creep model and flange contact has been employed to simulate the derailment response at high speed. The effect of vehicle speed running on a curved track was investigated for derailment quotient. The main aim of present research work to evaluate derailment quotient at the speed range of 150 kmph to 600 kmph for hard and soft suspension parameter. Derailment quotient has been calculated for both linear and nonlinear creep models and it is seen that DQ for linear model has a lower value compare to non linear creep. The major advantages of the proposed model are that, the presented model can actively predict the derailment of a railway vehicle, and also precisely determine the nonlinear critical hunting speeds.

Wheel nominal rolling radius difference on hunting stability of railway vehicle system under a speed-dependent nonlinear creep model

2017 ◽  
Vol 24 (14) ◽  
pp. 3107-3123
Author(s):  
Yung-Chang Cheng ◽  
Po-Hsien Wu
Keyword(s):  
Degrees Of Freedom ◽  
Creep Model ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
Nonlinear Creep ◽  
Original Design ◽  
Vehicle System ◽  
Wheel Radius ◽  
Hunting Stability ◽  
Stiffness And Damping

This study presents the hunting stability of a railway vehicle system in a speed-dependent nonlinear creep model with varying wheel conicity and nominal rolling radius. Integrating Kalker’s linear theory, Hertz contact theory, and the heuristic nonlinear creep model, the speed-dependent nonlinear creep model, including the semi-axis lengths and nonconstant creep coefficients with the varying vehicle speed, is investigated. Modeling and dynamic analysis are performed in the 28 degrees-of-freedom railway vehicle system. Lyapunov’s indirect method is used to calculate critical hunting speed of a railway vehicle system. The effects of suspension system parameters, various wheel conicities, and nominal rolling radii on the hunting stability are illustrated and compared. Critical hunting speeds calculated for the original design wheel are consistently better than those obtained from worn wheels with differences in wheel conicity and wheel rolling radius. Notably, critical hunting speeds calculated for a softer stiffness and damping decrease as wheel nominal rolling radius difference increases. Furthermore, the critical hunting speed calculated by the harder stiffness and damping increase as wheel nominal rolling radius difference increases. Analysis of hunting stability further shows that vehicle running speed must be considered when the wheel nominal rolling radius is less than the origin design wheel radius. Therefore, the effects of various wheel nominal rolling radius differences on hunting stability is an important research issue.

Hunting stability analysis of a railway vehicle system using a novel non-linear creep model

2012 ◽  
Vol 226 (6) ◽  
pp. 612-629 ◽  
Author(s):  
Yung-Chang Cheng
Keyword(s):  
Degrees Of Freedom ◽  
Lateral Displacement ◽  
Creep Model ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
System Parameters ◽  
Proposed Model ◽  
Linear Creep ◽  
Non Linear ◽  
Six Dof

A non-linear creep model that considers non-constant creep coefficients that vary as a function of vehicle speed is derived using Hertz contact theory, Kalker’s linear theory and a heuristic non-linear creep model. The proposed model is created by modifying the heuristic non-linear creep model by adding a linear creep moment and the semi-axis lengths in the non-linearity of the saturation constant. In this paper, the vehicle is modeled by a system with 28 degrees of freedom, taking into consideration the lateral displacement, vertical displacement, roll angle and yaw angle of each wheelset, the truck frames and car body. To analyze the respective effects of the major system parameters on the vehicle dynamics, the 28 degree-of-freedom (DOF) system is reduced to a 25-DOF model, by excluding designated subsets of the system parameters. The accuracy of the present analysis is verified by comparing a six-DOF system and the current numerical results with results in the literature. The effects of suspension parameters of a vehicle on the critical hunting speeds evaluated by the currently proposed model, the traditional non-linear creep model and the linear creep model are illustrated. In most cases, the obtained results show that the critical hunting speed evaluated using the new non-linear creep model is greater than that derived using the traditional non-linear creep model. Additionally, the critical hunting speed evaluated using the linear creep model is higher than that evaluated using the currently proposed non-linear creep model.

Derailment Analysis of High-Speed Railway Vehicle Bogies

2011 ◽  
Vol 110-116 ◽  
pp. 186-195 ◽  
Author(s):  
Yung Chang Cheng ◽  
Chern Hwa Chen ◽  
Che Jung Yang
Keyword(s):  
High Speed ◽  
Lateral Displacement ◽  
Vertical Displacement ◽  
Creep Model ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
Nonlinear Creep ◽  
Bogie Frame ◽  
Suspension Parameters ◽  
Yaw Angle

Based on the heuristic nonlinear creep model, the nonlinear coupled differential equations of the motion of a 12 degree-of-freedom (12-DOF) bogie system which takes account of the lateral displacement, vertical displacement, the roll angle and the yaw angle of the each wheelset and the bogie frame, moving on curved tracks are derived. The nonlinear creep forces and moments are constructed via the saturation constant of the nonlinear creep model in completeness. The effect of the suspension parameters of a bogie system on the derailment quotient is investigated. Results obtained in this study show that the derailment quotient of a bogie system increases as the vehicle speed increases. In addition, the derailment quotient of a bogie system is generally decreased with the increasing values of suspension parameters.

scholarly journals Prediction of Theoretical Derailments Caused by Cross-Winds with Frequency

2021 ◽  
Vol 11 (7) ◽  
pp. 2947
Author(s):  
JunWoo Kim ◽  
InHo Song ◽  
JeongSeo Koo
Keyword(s):  
High Speed ◽  
Technical Specification ◽  
Design Stage ◽  
Railway Vehicle ◽  
International Union ◽  
Running Safety ◽  
Wind Speeds ◽  
Rail Irregularities ◽  
Wind Frequency ◽  
Theoretical Results

In this paper, theoretical derailment equations for cross-wind with frequency were derived to assess running safety. For a KTX (Korean high-speed train) unit, the wheel unloading ratios, which are the criteria for evaluating derailments in UIC (International union of railways) and TSI (Technical Specification for Interoperability) regulations, were calculated through the formula under the driving regulations according to cross-wind speeds, and the theoretical results were compared and evaluated through a multibody dynamics (MBD) simulation. In addition, the wheel unloading ratios were calculated for various frequencies of cross-winds. As a result of the formula and MBD, the wheel unloading ratios were shown to increase rapidly regardless of the dampers in suspension when the cross-wind frequency and the natural frequency of a vehicle were in agreement. Finally, we calculated the changes of wheel unloading ratio for different track gauges and found that these theoretical equations could calculate more accurate results than the existing Kunieda’s formula. The formula derived in this study has the advantage of considering various variables, such as fluctuant cross-winds, rail irregularities, and derailment behaviors, which were not considered in previous studies or Kunieda’s formula. It could be used for setting suspensions or railway vehicle specifications in the initial design stage.

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