Effect of the first two wheelset bending modes on wheel-rail contact behavior
07 Dec 2014-Journal of Zhejiang University Science (Zhejiang University Press)-Vol. 15, Iss: 12, pp 984-1001
TL;DR: In this article, a new wheel-rail contact model was developed for considering the effect of wheel-set bending deformation on wheelrail contact behavior at high speeds, which is suitable for high-speed vehicles.
Abstract: The objective of this paper is to develop a new wheel–rail contact model, which is suitable for considering the effect of wheelset bending deformation on wheel–rail contact behavior at high speeds. Dummies of the two rigid half wheelsets are introduced to describe the spacial positions of the wheels of the deformed wheelset. In modeling the flexible wheelset, the first two wheelset bending modes are considered. Based on the modal synthesis method, these mode values of the wheelset axle are used to solve the motion equations of the flexible wheelset axle modeled as an Euler–Bernoulli beam. The wheel is assumed to be rigid and always perpendicular to the deformed axle at the wheel center. In the vehicle model, two bogies and one car body are modeled as lumped masses. Spring–damper elements are adopted to model the primary and secondary suspension systems. The ballasted track is modeled as a triple-layer discrete elastic supported model. Two high-speed vehicle–track models, one considering rigid wheelset models and the other considering flexible wheelset models, are used to analyze the differences of the numerical results of the two models in both frequency and time domains. In the simulation, a random high-speed railway track irregularity is used as wheel–rail excitations. Wheel–rail forces are calculated and analyzed in the time and frequency domains. The results clarify that this new contact model can characterize very well the influence of the first two bending modes of the wheelset on contact behavior.
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TL;DR: The characteristics, effects, causes, and solutions of wheel polygonisation in metro vehicles, locomotives, and high-speed trains in China are summarized and guidance is provided on further understanding the formation mechanisms, monitoring technology, and maintenance criterion of wheel Polygonisation.
Abstract: Polygonisation is a common nonuniform wear phenomenon occurring in railway vehicle wheels and has a severe impact on the vehicle–track system, ride comfort, and lineside residents. This paper first summarizes periodic defects of the wheels, including wheel polygonisation and wheel corrugation, occurring in railways worldwide. Thereafter, the effects of wheel polygonisation on the wheel–rail interaction, noise and vibration, and fatigue failure of the vehicle and track components are reviewed. Based on the different causes, the formation mechanisms of periodic wheel defects are classified into three categories: (1) initial defects of wheels, (2) natural vibration of the vehicle–track system, and (3) thermoelastic instability. In addition, the simulation methods of wheel polygonisation evolution and countermeasures to mitigate wheel polygonisation are presented. Emphasis is given to the characteristics, effects, causes, and solutions of wheel polygonisation in metro vehicles, locomotives, and high-speed trains in China. Finally, the guidance is provided on further understanding the formation mechanisms, monitoring technology, and maintenance criterion of wheel polygonisation.
94 citations
TL;DR: In this article, the authors discuss some key problems faced in high-speed train operation such as wheel tread concave wear causing the lateral oscillation of the train in operation, wheel roundness higher-order polygonal wear leading to fierce vertical vibration of wheel/rail and abnormal vibration noise of the coach interior of a train thus causing loosening and cracking of train bogie parts, short pitch rail corrugation generation on the part of the track.
Abstract: This paper discusses some key problems faced in high-speed train operation. These problems include: wheel tread concave wear causing the lateral oscillation of the train in operation, wheel roundness higher-order polygonal wear leading to fierce vertical vibration of wheel/rail and abnormal vibration noise of the coach interior of the train thus causing loosening and cracking of the train bogie parts, short pitch rail corrugation generation on the part of the track, fracture of cushion layer and road base fracture of the track, and increased noise inside and outside the train. At present, the mechanism of the occurrence and development of these phenomena is still not fully understood. This paper briefly reviews the related research on these problems in China and abroad, including many important recent papers and the articles published in this special issue. They make outstanding contributions to solving these problems, and include important work on train-track coupling large system theory, the relationship theory and technique of wheel/rail, and the vibration-noise reduction technology of the train.
67 citations
TL;DR: A three-dimensional dynamic model of a high-speed train coupled with a ballast track for dynamic derailment analysis is presented, in which the commonly used derailment safety assessment criteria around the world are embedded in the simulation model.
Abstract: The running safety of high-speed trains has become a major concern of the current railway research with the rapid development of high-speed railways around the world. The basic safety requirement is to prevent the derailment. The root causes of the dynamic derailment of high-speed trains operating in severe environments are not easy to identify using the field tests or laboratory experiments. Numerical simulation using an advanced train-track interaction model is a highly efficient and low-cost approach to investigate the dynamic derailment behavior and mechanism of high-speed trains. This paper presents a three-dimensional dynamic model of a high-speed train coupled with a ballast track for dynamic derailment analysis. The model considers a train composed of multiple vehicles and the nonlinear inter-vehicle connections. The ballast track model consists of rails, fastenings, sleepers, ballasts, and roadbed, which are modeled by Euler beams, nonlinear spring-damper elements, equivalent ballast bodies, and continuous viscoelastic elements, in which the modal superposition method was used to reduce the order of the partial differential equations of Euler beams. The commonly used derailment safety assessment criteria around the world are embedded in the simulation model. The train-track model was then used to investigate the dynamic derailment responses of a high-speed train passing over a buckled track, in which the derailment mechanism and train running posture during the dynamic derailment process were analyzed in detail. The effects of train and track modelling on dynamic derailment analysis were also discussed. The numerical results indicate that the train and track modelling options have a significant effect on the dynamic derailment analysis. The inter-vehicle impacts and the track flexibility and nonlinearity should be considered in the dynamic derailment simulations.
51 citations
TL;DR: In this paper, a long-term iterative wear model is proposed to predict the development of polygonal wear of railway wheels, and two new strategies to investigate wheel polygonization are proposed.
31 citations
TL;DR: In this paper, a 3D coupling dynamic model of a vehicle and a China railway track system I (CRTS-I) slab track is developed to study the effect of CAM softening on track damage.
Abstract: Cement asphalt mortar (CAM) softening is a common phenomenon that results from aging and rain soaking when a high-speed railway is in service. CAM softening seriously affects vehicle operation safety and track dynamics. In this paper, a 3D coupling dynamic model of a vehicle and a China railway track system I (CRTS-I) slab track is developed. By using the proposed model, the wheel-rail contact forces, derailment coefficient, wheelset loading reduction ratio, and the track displacements are calculated to study the influences of CAM softening on the dynamic characteristics of a vehicle-track system. A track-subgrade finite difference model is developed to study the effect of CAM softening on track damage. The results show that track interface shear failure develops when the CAM softening coefficients reach 10–100. The CAM softening coefficient should not be less than 1000, otherwise a high-speed running vehicle may risk derailment.
23 citations
Cites background from "Effect of the first two wheelset be..."
...Much research work on vehicletrack coupling dynamics and track-subgrade dynamics was carried out (Chen et al., 2014; Ling et al., 2014; Zhong et al., 2014)....
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References
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01 Jan 2012
TL;DR: In this article, a time-domain model for the prediction of long-term rail roughness growth on small radius curves is presented, where both lowfrequency vehicle dynamics due to curving and high-frequency vehicle-track dynamics excited by short-wavelength rail irregularities are accounted for.
Abstract: A time-domain model for the prediction of long-term rail roughness growth on small radius curves is presented. Both lowfrequency vehicle dynamics due to curving and high-frequency vehicle-track dynamics excited by short-wavelength rail irregularities are accounted for. The influence of non-Hertzian and non-steady effects in the wheel-rail contact model on rail wear is studied. The model features a refined contact detection algorithm that accounts for wheelset yaw angle as well as surface irregularities and structural flexibilities of wheelset and rail. The development of corrugation on a small radius curve is found to be highly influenced by the wheel-rail friction coefficient. For vehicle speed 25 km/h and friction coefficient 0.3, predictions of long-term roughness growth on the low rail generated by the leading wheelset show decreasing magnitudes in the entire studied wavelength interval. For friction coefficient 0.6, roughness growth is found at several wavelengths. The corresponding calculation for the high rail contact indicates no roughness growth generated by the trailing wheelset independent of friction coefficient. The importance of accounting for the phase between the calculated wear and the present rail irregularity is demonstrated.
26 citations
TL;DR: In this paper, the authors investigate the influence of the parametric excitation from the track as well as static and dynamic unbalances of wheels and brake disks on the dynamic response of the wheelset running at various speeds on the track of various average vertical stiffness.
Abstract: In the paper, dynamic interaction between elastic high-speed-train car wheelset and track is studied using a discrete-continuous mechanical model. The model enables to investigate the influence of the parametric excitation from the track as well as static and dynamic unbalances of wheels and brake disks on the dynamic response of the wheelset running at various speeds on the track of various average vertical stiffness. From the results of numerical simulation it follows that particularly severe periodic resonances occur for the track of large stiffness, yielding high vertical dynamic contact forces between the wheels and rails. The maximum dynamic response has been obtained for parameters corresponding to the conditions at which the phenomenon of grumbling noise generation is usually observed in reality.
26 citations
"Effect of the first two wheelset be..." refers background in this paper
...The second is a continuous model developed by Szolc (1998a; 1998b), in which the wheelset axle was modeled as a beam, and two wheels and brake discs were modeled as rigid rings attached to the axle through a massless, elastically isotropic membrane....
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TL;DR: In this paper, a time-domain model for the prediction of long-term growth of rail roughness (corrugation) on small radius curves is presented, and the influence of non-Hertzian and non-steady effects in the wheel-rail contact model on rail wear is studied.
25 citations
"Effect of the first two wheelset be..." refers methods in this paper
...In (Torstensson et al., 2012; Torstensson and Nielsen, 2011), the contact point detection was done before the simulation and used in the subsequent time integration analysis in the form of look-up table....
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01 Jan 2003
TL;DR: In this paper, the influence of initial out-of-roundness of wheels as well as their unbalances at high speeds on the wear process of a wheel is discussed.
Abstract: High-speed trains in Germany often suffer from vibrations of the car body in the so-called medium-frequency range (30–300 Hz), also known as 100 Hz droning noise. The reason of this unpleasant phenomenon is the development of out-of-round wheels. This paper will discuss the influence of initial out-of-roundness of wheels as well as the influence of wheelset unbalances at high speeds on this wear process. Using a modular approach the model of the wheelset based on the method of flexible multibody systems is coupled to the rail with a complex wheelrail contact module. In order to account for the long-term wear effects on the wheels the mechanical model is extended by a long-term wear model using a wearfeedback loop in a different time scale. The presented results of wear simulations are subsequently used to discuss the influence of initial out-of-roundness and wheelset unbalances at high speeds on the order and magnitude of developing wear patterns.
23 citations
TL;DR: In this paper, the dynamic interaction between a wheelset of a high-speed train car and a railway track is considered with the help of a discrete-continuous mechanical model.
Abstract: SUMMARY In the present paper, the dynamic interaction between a wheelset of a high-speed-train car and a railway track is considered with the help of a discrete-continuous mechanical model. This model enables us to investigate the bending-torsional-axial vibrations of the wheelset coupled with the vertical and lateral vibrations of the track through the wheel-rail contact forces. The results of numerical simulations performed for the wheelset motion both on straight and curved tracks demonstrate qualitative similarities of the corresponding dynamic responses of the system and essential quantitative differences of the respective amplitude and average values. Particularly severe interaction between the wheelset and the track is observed in the form of periodic resonances caused by parametric excitation from the track.
18 citations
"Effect of the first two wheelset be..." refers background in this paper
...The second is a continuous model developed by Szolc (1998a; 1998b), in which the wheelset axle was modeled as a beam, and two wheels and brake discs were modeled as rigid rings attached to the axle through a massless, elastically isotropic membrane....
[...]