Vibrations due to the passage of a railway vehicle on straight and curved tracks (original) (raw)
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Analysis of lateral vibrations of railroad due to the passage of the underground train
In the paper results of vibration measurements on the base of the railroad in tunnels and classical track are presented. Measurements were performed at straight and curved sections of the track. The analysis is focused on the influence of the lateral slip in rail/wheel contact zone on the generation of vibrations and a noise. The numerical model of a rail vehicle built in the fortran reveals in a dynamic response of a similar quality to the results registered on the real track and on the laboratory stand were obtained. Results were compared with the experimental findings of rolling of a wheel with lateral sleep. In all cases double periodic oscillations are observed.
Vibrational impact of high-speed trains. I. Effect of track dynamics
The Journal of the Acoustical Society of America, 1996
The dramatic increase in speeds of modern passenger trains makes it important to consider the vibrational impact of such trains on the built environment. In the author's earlier paper in which a quasistatic approach to the calculation of track deflection curves had been used ͓V. V. Krylov, Appl. Acoust. 44, 149-164 ͑1995͔͒, it had been shown that a very large increase in generated ground vibration level ͑about 70 dB, as compared to conventional trains͒ may occur if train speed exceeds the velocity of Rayleigh surface waves in the ground. Such a situation might arise, for example, with French TGV trains for which speeds over 515 km/h have been achieved. The present paper investigates the effect of track bending waves propagating in the system track/ground on railway-generated ground vibrations. It is shown that for train speeds approaching the minimal phase velocity of bending waves the level of generated ground vibrations is reduced. Theoretical results are illustrated by numerically calculated frequency spectra of ground vibrations generated by single axle loads traveling at different speeds and by TGV or Eurostar high-speed trains.
RAILWAY TRAFFIC VIBRATIONS: GENERATION AND PROPAGATION - THEORETICAL ASPECTS
The interest in vibrations due to railway traffic is increasing in all developed countries, and it requires to develop both experimental and theoretical studies. In fact, innovative track can reduce the transmission of vibrations toward buildings and people, but also a better knowledge of the physical phenomenon can be useful to apply other methodologies, like a better control of contact surface characteristics. Theoretical mechanical models, based on the analysis of dynamic interaction between wheel and rail, and between track and formation soil, are the key tool to understand the phenomenon and evaluate interventions. In the paper, after a review of principles of vibration theory, two different calculation models are presented: the first one is a mathematical model for the analysis of dynamic loads caused by rail and wheel irregularities, the second one is useful to study the transmission of vibrations in the railway track and soil. The models, which can be used in sequence, are valid for various applications, in particular concerning the analysis of the role of different system components (wheels, rail, track) and their importance in the generation and propagation problems of railway vibrations.
2022
One of the most acute problems faced today by Railway Transport Companies is the rapid wear of locomotive wheel borders in the freight transport. Hence, the purpose of this article is to find ways to reduce the forces acting on the wheels of railway vehicles, generally during their movement in small radius turns. For means of simplification has been assumed that the train is moving at uniform speed during a curved path. Analyzing the scheme of action of forces on the pair of wheels, we see that one of the ways to reduce this consumption phenomenon is to reduce the parasitic moment of frictional forces. With reference to the practice of roller-contact studies, we modeled mathematically the redistribution of frictional forces at the point of contact of the wheel-rail pair and realized two computer models for two variants of wheel profiles: conical and curved.
Advances in Science and Technology Research Journal
Purpose of the article is to demonstrate that a high-speed electric locomotive, driven by asynchronous motors in a hollow shaft arrangement and swing-out couplings, can generate corrugation conditions on the surface of new and smooth rails on straight and curved track. Most studies carried out in this area is usually concerned with the response of the power train to kinematic excitation from a track where corrugations are already present. The novelty of the look presented in the article is to establish the influence of the vehicle's driveline and the parameters of a perfectly smooth formation track on the mechanism of corrugation. A four-axle EU11 electric locomotive, produced in Poland in the late 1990s, has been selected for analysis. A complete electro-mechanical model of the locomotive was built using the Vi-Rail software and prepared for simulation on straight and curved track. A non-linear model of wheel-rail contact was included and the contact forces were determined for the locomotive model in motion with the active power system. Unbalanced inertia forces generated by the scattering of stiffness characteristics of the coupling links, have been included to the propulsion system as an additional source of dynamic excitations. The complexity of the obtained results was influenced by the fact that simulation studies were carried out in both the time and frequency domains. The results obtained in the time domain were used to calculate the vertical and torsional vibration frequencies with respect to the driving wheelsets. One of the most important results of the simulation studies carried out is the determination of the effect of locomotive acceleration on the frequency of resonant torsional vibrations of the wheelsets in straight and curved track traffic.
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 2012
This article presents a mathematical model aimed at predicting wheel–rail contact vibration force arising from wheel profile irregularities. Prediction of vibrations caused by a passing train is a basic factor in environmental impact studies related to planning new railway lines. The prediction model is useful during the development of a project as it facilitates selection of the most suitable track for reducing vibration levels. This article presents the model, analyses the influence of the track base on the vibration-generating mechanisms, and compares the dynamic behaviour of the most widely used urban railway tracks.
Mathematical and Computer Modelling, 2011
In recent years, ground vibrations have become an important issue due to the growing awareness of the society about environmental living conditions. In this way, vibrations caused by trains running near houses or workplaces are considered disturbing for residents. Within this framework, this paper presents a procedure to estimate the vibration path caused by the passing of a train. In order to achieve this, the equations which describe the physical phenomenon are set in the frequency and wavenumber domain and solved by using the Fourier Transform. The obtained analytical solution is transformed back into the time and space domain by means of the Fourier series. The obtained theoretical results are compared with experimental measurements carried out in the Madrid-Barcelona High Speed Line in order to analyse the performance of this procedure.
Transport Problems
In this article, the considered principles for the development of calculation schemes and the subsequent formation of vibration equations are a special case of classical simulation of motion in space of solid body systems connected in space by kinematic connections. This approach is useful with limited computational capabilities and an assumption of the relatively small body movements inherent in railway crew bodies, and reduces the task of motion research to analysis of fluctuations. Various design schemes of freight car truck, mathematical modeling of systems dynamics, "crew-track" safety of freight car movement and withdrawal under different technical conditions of running parts and track are considered in this work.
Journal of Theoretical and Applied Mechanics, 2016
Dynamic behavior of a track-train system is a function of axle loads and support stiffness because of non-linear supports. Therefore, it is expected that the support stiffness affects the behavior of the railway track during passing of a light or heavy car body. Since the effects of axle loads caused by light and heavy railway vehicles and support stiffness of ballasted railway tracks due to passing railway vehicles have not been studied adequately, therefore the present study focused on this issue. For this purpose, this issue was first investigated by passing a light and heavy car body including bogies with three axle loads as field tests. Then, numerical analyses of the railway track caused by the passing of these railway vehicles were studied, and the numerical results were compared with the field results. There was a good agreement between the values of field responses and numerical analyses. Subsequently, a series of sensitivity analyses on effects of the axle loads caused by light or heavy loading and support conditions was done on the ballasted railway track. The results indicated that the maximum vertical displacements increased by axle loads, increased sleeper distances and decreases support stiffness. Finally, equations of track behavior based on support stiffness and axle loads were derived.