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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TL;DR: In this paper, a new method is presented for the analysis of complex dynamic systems which is based on partitioning the system degrees of freedom into a "global" set and a "local" set.
Abstract: A new method is presented for the analysis of complex dynamic systems which is based on partitioning the system degrees of freedom into a “global” set and a “local” set. The global equations of motion are formulated and solved in a standard deterministic manner, although due account is taken of the presence of the local degrees of freedom via an approach which is analogous to fuzzy structure theory. The local equations of motion are formulated and solved by using statistical energy analysis (SEA) with due account being taken of power input from the global degrees of freedom. The method can be considered to encompass a number of existing analysis techniques and to form a flexible framework within which a number of detailed modeling strategies can be devised. A simple rod system provides an initial application, and it is shown that the method yields very good results from low to high frequency excitation.
219 citations
TL;DR: In this paper, the authors show the development starting with the massless wheelset model and ending with sophisticated elastic multibody system models for the vehicle and track, different mathematical approaches in frequency and time domain are compared.
Abstract: During the last years railway companies have observed increasing problems with track damage like rail corrugation, deterioration of ballast or unround wheels. Since the origin of these damages is suspected in the mid-frequency dynamics, research activities in the frequency range from 50 up to 500 Hz have been initiated. The article demonstrates that in comparison to the low and high frequency range the knowledge about physical effects in the mid-frequency range is poor. Apart from a historical literature review on vehicle and track modelling, recently published methods and models are collated and problems in their mathematical treatise are mentioned. Regarding the vehicle, the paper shows the development starting with Klingel's massless wheelset model and ending with sophisticated elastic multibody system models. Concerning the track, different mathematical approaches in frequency and time domain are compared. In the mid-frequency range the pad, ballast and subsoil properties play an important role. Hence...
174 citations
"Effect of the first two wheelset be..." refers background in this paper
...This model can describe the bending and torsional motions of the wheelset with only a few degrees of freedom, which could not be applied to studying wear phenomena on wheel treads or rails (Popp et al., 1999)....
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TL;DR: In this paper, the authors surveyed the causes and consequences of wheel/rail wear that is non-uniform in magnitude around/along the running surface and suggested remedies to relieve the problems.
Abstract: Summary High-frequency train-track interaction and mechanisms of wheel/rail wear that is non-uniform in magnitude around/along the running surface are surveyed. Causes, consequences and suggested remedies to relieve the problems are discussed for three types of irregular wheel/rail wear: (1) short-pitch rail corrugation on tangent tracks and large radius curves, (2) wheel corrugation as caused by tread braking, and (3) wheel polygonalisation. The state-of-the-art in modelling of dynamic train-track interaction in conjunction with prediction of irregular wear is reviewed.
160 citations
"Effect of the first two wheelset be..." refers background in this paper
...…and wheel out-of-roundness (OOR) generate high-frequency components of the dynamic wheel-rail contact forces that contribute significantly to the total wheel-rail contact forces (Nielsen et al., 2003), and reduce the life of the components of track and vehicle, such as wheels, rails, and fasteners....
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TL;DR: The theory behind the hybrid method combining FE and SEA for predicting the steady-state response of vibro-acoustic systems with uncertain properties is summarized and a number of detailed numerical and experimental validation examples for structure-borne noise transmission are presented.
Abstract: The finite element (FE) and statistical energy analysis (SEA) methods have, respectively, high and low frequency limitations and there is therefore a broad class of "mid-frequency" vibro-acoustic problems that are not suited to either FE or SEA. A hybrid method combining FE and SEA was recently presented for predicting the steady-state response of vibro-acoustic systems with uncertain properties. The subsystems with long wavelength behavior are modeled deterministically with FE, while the subsystems with short wavelength behavior are modeled statistically with SEA. The method yields the ensemble average response of the system where the uncertainty is confined in the SEA subsystems. This paper briefly summarizes the theory behind the method and presents a number of detailed numerical and experimental validation examples for structure-borne noise transmission.
143 citations
TL;DR: In this article, an existing multibody system model for simulation of general three-dimensional train-track interaction (accounting for frequencies up to several kHz) is extended with rolling contact mechanics according to FASTSIM.
Abstract: The objective of this study is to develop a tool for investigation of wheel tread polygonalization with radial irregularities including 1 to 20 wavelengths around the circumference of the wheel. Therefore, an existing multibody system model for simulation of general three-dimensional train–track interaction (accounting for frequencies up to several kHz) is extended with rolling contact mechanics according to FASTSIM. Furthermore, the model is also modified to allow for general wheel–rail profiles. The numerical model uses the concept of an iteration scheme including simulation of dynamic train–track interaction in the time domain coupled with a long-term wear model. A demonstration example including a bogie of a subway train travelling on a straight track is presented. In the example, an initial wheel out-of-roundness (OOR) is applied to the wheels. This irregularity is based on an amplitude spectrum derived from measurements on new wheels. Simulation results show that the most important wavelength-fixing...
142 citations