Dynamic Model Of Railway Vehicle Research Articles

Vibration and Stress Response of High-Speed Train Gearboxes under Different Excitations

The vibration data of the gearbox on a high-speed train was measured, and the vibration characteristics were analyzed in this paper. The dynamic stress of the gearbox under the internal and external excitation was examined by a railway vehicle dynamic model with a flexible gearbox and a flexible wheelset. The ideal 20th polygonal wear was considered, and dynamic stresses of the gearbox under different polygonal wear amplitudes were calculated. The gear transmission model was established to study the dynamic stress of the gearbox under the influence of the time-varying stiffness of the gear meshing. Based on the rigid–flexible coupling model, and considering the influence of wheel polygonization, gear meshing time-varying stiffness, and wheelset elastic deformation, the dynamic stress of the gearbox was investigated with consideration of the measured polygonal wear and measured rail excitation. The results show that the dynamic stress of the gearbox is dominated by the wheel polygonization. Moreover, not only the wheel polygonization excites the resonance of the gearbox, but also the flexible deformation of the wheelset leads to the deformation of the gearbox, which also increases the dynamic stress of the gearbox. Within the resonant bandwidth of the frequency, the amplitude of the dynamic stresses in the gearbox will increase considerably compared with the normal case.

The effect of gear meshing on the high-speed vehicle dynamics

The gear transmission system is a key part to transmit power for the electrical multiple unit (EMU) and to move the train forward. Its dynamic vibrations affect the operation safety and the dynamic characteristics of the vehicle. Based on the parameters of a certain type of high-speed EMU in China, a rigid-flexible coupling dynamics model of railway vehicle is developed. A flexible gear meshing dynamics model is built and it is incorporated into the vehicle system dynamics model. With the numerical method, the effect of the gear transmission on the dynamics of the high-speed vehicle is investigated. A field experiment is carried out and the measured accelerations of the gearbox are employed to validate the simulation results. The investigation results reveal that the gear meshing forces get large as the operation speed of the vehicle increases. Gear meshing affects the operation safety indexes and the vibrations of the bogie frames, motors and gearboxes, but has negligible effect on the vibrations of the carbody. The difference between the results with the flexible gear meshing model and the results with the rigid gear meshing model is negligible. The simulation acceleration is slightly smaller than the field test result of the gearbox.

Analysis of Resonant Vibration of Railway Vehicle

A fully equipped railway vehicle dynamic model which considers the car body flexibility is established to analyze the fundamental reason of car body flexural resonance. Results show that it is the geometric filtering phenomenon rather than the natural vibration of bogie bounce that causes the car body resonant flexural vibration. The higher the vehicle running speed, the higher the first vertical bending frequency should be required.

Research on The Control of Out-of-Round Wheel Profiles of High-Speed Railway Derived From Numerical Simulations

Periodic non-roundness of railway wheels will cause a series of variety on vehicle/track coupling system dynamic responses. A coupling dynamics model of railway vehicle with out-of-round wheels and track was built based on ADAMS/Rail. The effect of periodic non-roundness of wheel on the dynamical behavior of the vehicle system was analyzed. The numerical results regarding the misalignments of the vehicle and wheelset, the vertical wheel/rail contact forces and the reduction in the wheelset loading are presented under the conditions in which the wheels are in out-of-round and the train speed is from 200 km/h to 350 km/h. The results show that the dynamical vertical wheel/rail interaction forces are much related to the wheel out-of-roundness status. The critical range of the wheel out-of-roundness is determined according to the traditional criterion of wheelset loading reduction for safely running estimation. Itâ??s pointed out that out-of-round railway wheels can be detected by wheel/rail interaction force real-time monitoring system to guarantee safety and to minimize costs for repair and maintenance.

Evaluation of odometry algorithm performances using a railway vehicle dynamic model

In modern railway Automatic Train Protection and Automatic Train Control systems, odometry is a safety relevant on-board subsystem which estimates the instantaneous speed and the travelled distance of the train; a high reliability of the odometry estimate is fundamental, since an error on the train position may lead to a potentially dangerous overestimation of the distance available for braking. To improve the odometry estimate accuracy, data fusion of different inputs coming from a redundant sensor layout may be used. Simplified two-dimensional models of railway vehicles have been usually used for Hardware in the Loop test rig testing of conventional odometry algorithms and of on-board safety relevant subsystems (like the Wheel Slide Protection braking system) in which the train speed is estimated from the measures of the wheel angular speed. Two-dimensional models are not suitable to develop solutions like the inertial type localisation algorithms (using 3D accelerometers and 3D gyroscopes) and the introduction of Global Positioning System (or similar) or the magnetometer. In order to test these algorithms correctly and increase odometry performances, a three-dimensional multibody model of a railway vehicle has been developed, using Matlab-Simulink™, including an efficient contact model which can simulate degraded adhesion conditions (the development and prototyping of odometry algorithms involve the simulation of realistic environmental conditions). In this paper, the authors show how a 3D railway vehicle model, able to simulate the complex interactions arising between different on-board subsystems, can be useful to evaluate the odometry algorithm and safety relevant to on-board subsystem performances.

Effect of Ovalization of High Speed Railway Wheels on Vehicle Dynamic Performance

A coupling dynamics model of railway vehicle with oval wheels and track is built and a corresponding numerical method is developed.The effect of ovalization of the wheels on the dynamical behavior of the vehicle system is analyzed in details.The numerical results regarding the misalignments of the vehicle and wheelset,the dynamical normal loads of the wheels and the rails and the reduction in the wheelset loading are presented under the conditions in which the wheels are in ovalization and the train speed is from 200 km/h to 350 km/h.The limit of the wheel ovalization is determined according to the traditional criterion of wheelset loading reduction for safely running estimation.The results show that the dynamical behavior of the vehicle are much related to the wheel ovalization status(the difference between the maximum diameter and the minimum diameter of the elliptical wheel),the phase between the elliptical shapes of the two side wheels and the train speed.The wheel ovalization under high speed greatly influences the vehicle behavior.The lateral motion ability and the running quality of the vehicle quickly reduce with an increasing in the wheel ovalization,and the dynamical normal load increases greatly.In such a situation,it is affirmed that the use lives of the parts of the vehicle and the track would be much reduced.And also the risk of derailment is increased largely.

Effect of a scratch on curved rail on initiation and evolution of plastic deformation induced rail corrugation

A calculation model is put forward to analyze the effect of a scratch on the running surface of a curved rail on initiation and growth of plastic deformation induced rail corrugation when a wheelset is steadily and repeatedly curving. The numerical method considers a combination of Carter’s two-dimensional contact theory, a two-dimensional elastic–plastic finite element model and a vertical dynamics model of railway vehicle coupled with a curved track. A concept of feedback between the corrugation development and the vertical coupling dynamics of the wheelset and track is involved. The cyclic ratchetting effect of the rail material under repeated contact loadings is taken into account. The numerical results indicate that when a vehicle runs on rails with a scratch the contact vibration between the wheel and rail occurs at large amplitude, and rail corrugation due to plastic deformation initiates and develops. The corrugation has a tendency to move along the running direction and its evolution rate decays as wheelset passages increase. The passing frequencies of the plastic deformation induced corrugation depend on the natural frequencies of the track. The residual stresses stabilize after a limited number of wheelset passages. The residual strains increase at a reduced rate with increasing wheelset passages.

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

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.

SEMI-ACTIVE CONTROL OF RAILWAY VEHICLE STRUCTURE VIBRATION BASED ON MR DAMPER

Based on the flex-rigid multi-body system dynamics model of railway vehicle, the first vertical bend structure modal and vertical and pitch rigid vibration of carbody which reduce the ride quality are controlled using independent modal space control (IMSC) and optimum control theory. A semi-active control strategy using MR damper is proposed to decease the vibration acceleration of the vehicle on the floor, to improve the ride quality of railway vehicle, and to save the energy consumed. The co-simulation of the full vehicle mechanical and semi-active control system is finished in ADAMS and Mat lab//Simulink~(?) environment. The simulation results show that this semi-active control method according to shyhook damper control model is effective, the first bend structure modal of carbody is restrained and the vehicle running behaviour is improved. This semi-active MR damper used in railway vehicle can be designed.

틸팅 차량용 시뮬레이터 개발을 위한 철도차량 모델링

This paper presents a dynamic model of railway vehicle for the development of a 6-axis tilting train simulator. The tilting train simulator will be used to verify the tilting electronics and tilting control algorithm that are to be applied to the Korean tilting train. The tilting train simulator is composed of 6 electric-driven actuators, a track generation system, a graphic user interface, and a visualization system with a 1600㎜-diameter dome screen. The each system shares the data by means of ethernet network in realtime. In this study, a train model of 9-DOF with a force generation system to tilt train body has been developed. The dynamic analysis for the straight track running and curve negotiation of a railway vehicle can be performed in the model. In this study, a verification study for the application of the model to the simulator has been conducted under curving situation on the track with different radii.

Effect of rail corrugation on vertical dynamics of railway vehicle coupled with a track

The effect of rail corrugation on the vertical dynamics of railway vehicle coupled with a curved track is investigated in detail with a numerical method when a wheelset is steadily curving. In the calculation of rail corrugation we consider the combination of Kalker’s rolling contact theory modified, a model of material loss on rail running surface, and a dynamics model of railway vehicle coupled with a curved track. In the establishment of the dynamic model, for simplicity, one fourth of the freight car without lateral motions, namely a wheelset and the equivalent one fourth freight car body above it, is considered. The Euler beam is used to model the rails and the track structure under the rails is replaced with equivalent springs, dampers and mass bodies. The numerical results show the great influence of the rail corrugation on the vibration of the parts of the vehicle and the track, and the some characters of rail corrugation in development.

Effect of track irregularities on initiation and evolution of rail corrugation

The effect of track irregularities on rail corrugation is investigated in detail with the numerical method when a wheelset is steadily curving. The irregularities considered in the analysis include initial running surface of rail with periodically varying and different wave length, stochastic roughness on the rail running surface, and vertical uneven support stiffness of the rail due to the discrete sleeper supports. The numerical method considers a combination of Kalker's rolling contact theory with non-Hertzian to be modified, a linear frictional work model and a vertical dynamics model of railway vehicle coupled with a curved track. The model is also validated by an experiment with a full scale facility. The influence of different speeds of wheelset curving on the development of the corrugation is taken into account in the calculation. The numerical results indicate that (1) for existing of the initial corrugation of new rail with any wavelength the depth from the peak to trough of it decreases gradually with an increase of wheelset passage, but the initial corrugation evolved has a tendency to move in the rolling direction, (2) the amplitude of the initial stochastic roughness of new rail is gradually leveled out and but a corrugation with very small depth and a few fixed passing frequencies is initiated, the passing frequencies are the same as the natural frequencies of the track, and (3) the discrete rail supports by sleepers have a great influence on the formation of the corrugation.

Estimation of parameters in a linear state space model using a Rao-Blackwellised particle filter

A Rao-Blackwellised particle filter is used in the estimation of the parameters of a linear stochastic state space model. The proposed method combines the particle filtering technique with a Kalman filter using marginalisation so as to make full use of the analytically tractable structure of the model. Simulation studies are performed on a simple illustrative example and the results demonstrate the effectiveness of the proposed method in comparison with the conventional extended-Kalman-filler-based method. The proposed method is then applied in the estimation of the parameters in a railway vehicle dynamic model for condition monitoring and the desired results have been obtained.

Effect of a scratch on curved rail on initiation and evolution of rail corrugation

The effect of a scratch formed on the running surface of a curved rail, due to the slide of a locomotive wheel, on the formation and evolution of rail corrugation is investigated in detail with numerical methods when a wheelset is steadily and repeatedly curving. In the calculation we consider a combination of Kalker’s rolling contact theory with non-Hertzian to be modified, a linear frictional work model and a vertical dynamics model of railway vehicle coupled with a curved track. Also the influence of different speeds of wheelset curving through the scratch on the development of the corrugation is taken into account. The numerical results indicate that a scratch causes strong contact vibration between the wheel and rail, and initiation and development of rail corrugation under the condition of steady creepage occurring between the wheel and curved rail. The wave-length of the corrugation depends on the speed of wheelset curving and the natural frequencies of the track.