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Real Herraiz J.I.,Polytechnic University of Valencia | Morales-Ivorra S.,Polytechnic University of Valencia | Zamorano Martin C.,Foundation for the Research and Engineering in Railways | Soler Basauri V.,Polytechnic University of Valencia
Mathematical Problems in Engineering | Year: 2015

In recent years, there has been a significant increase in the development of the railway system. Despite the huge benefits of railways, one of the main drawbacks of this mode of transport is vibrations caused by vehicles in service, especially in the case of trams circulating in urban areas. Moreover, this undesirable phenomenon may be exacerbated by the presence of irregularities in the rail-wheel contact. Thus, an analytical model able to reproduce the vibrational behavior of a real stretch of tram track was implemented. Besides, a simulation of different types of corrugation was carried out by calculating in an auxiliary model the dynamic overloads generated by corrugation. These dynamic overloads fed the main model to obtain the vibrations generated and then transmitted to the track. © 2015 Julia I. Real Herráiz et al. Source


Montalban L.,Polytechnic University of Valencia | Zamorano C.,Foundation for the Research and Engineering in Railways | Morales S.,Polytechnic University of Valencia | Real J.I.,Polytechnic University of Valencia
Journal of Vibroengineering | Year: 2015

Different track typologies compel different dynamic behaviors. Thus, the sleepers’ material can play a key role in the wheel-rail contact forces and vibration generation phenomena. Furthermore, this situation can be increased if the vehicle speed is varied, accelerating track damages and maintenance operations. In order to assess the influence of sleepers’ materials and vehicle speed on the vibration generation phenomenon, this paper develops a vehicle-track interaction model by means of a Finite Elements model in ANSYS commercial software. The numerical model is calibrated and validated with real data and then used to compare the different response of a ballasted track with concrete and wooden sleepers and accelerating and braking trains in both time and frequency domains. The results indicate the importance of sleepers’ stiffness in the vibration generation phenomenon as well as the low sensitivity of vertical deflections to variations in the train speed. © 2015 JVE International Ltd. Source


Real J.I.,Polytechnic University of Valencia | Zamorano C.,Foundation for the Research and Engineering in Railways | Velarte J.L.,Polytechnic University of Valencia | Blanco A.E.,Polytechnic University of Valencia
Journal of Modern Transportation | Year: 2015

Imperfections in the wheel–rail contact are one of the main sources of generation of railway vibrations. Consequently, it is essential to take expensive corrective maintenance measures, the results of which may be unknown. In order to assess the effectiveness of these measures, this paper develops a vehicle–track interaction model in the time domain of a curved track with presence of rail corrugation on the inner rail. To characterize the behavior of the track, a numerical finite element model is developed using ANSYS software, while the behavior of the vehicle is characterized by a unidirectional model of two masses developed with VAMPIRE PRO software. The overloads obtained with the dynamic model are applied to the numerical model and then, the vibrational response of the track is obtained. Results are validated with real data and used to assess the effectiveness of rail grinding in the reduction of wheel–rail forces and the vibration generation phenomenon. © 2015, The Author(s). Source


Montalban L.,Polytechnic University of Valencia | Zamorano C.,Foundation for the Research and Engineering in Railways | Palenzuela C.,Polytechnic University of Valencia | Real J.I.,Polytechnic University of Valencia
European Journal of Environmental and Civil Engineering | Year: 2015

Loading conditions on railway tracks are the result of the sum of the static axle load of vehicles and augments caused by dynamic effects. Dynamic loads have several causes and can be quasi-static or impacts. Cracking in pre-stressed concrete sleepers is mainly due to these impact loads and vibrations, converting the central and the rail seat sections of the critical sections in sleepers. This paper presents the development of a finite element model of a cracked sleeper that may be adapted to every condition of damage related to cracking. Cracks have been modelled as volumes characterised by a lower stiffness in order to simulate the loss of inertia. The models have been updated in terms of the frequencies of the first three bending modes of vibration of cracked and uncracked sleepers, obtained using experimental modal analysis technique, as presented in previous authors work. The updating process led to the mechanical properties that define the whole model. Results point out that frequencies obtained with the numerical model agree experimental data obtained in laboratory. These models may be used in further investigations to predict the static influence of cracked sleepers in complete finite element models of ballasted railway tracks. © 2014 Taylor & Francis. Source


Real-Herraiz J.,Polytechnic University of Valencia | Zamorano-Martin C.,Foundation for the Research and Engineering in Railways | Real-Herraiz T.,Polytechnic University of Valencia | Morales-Ivorra S.,Polytechnic University of Valencia
Latin American Journal of Solids and Structures | Year: 2016

Important track degradation occurs in structure-embankment transitions, in which an abrupt change in track vertical stiffness arises, leading to a reduction in passengers comfort and safety. Although granular wedges are suggested by different railroad administrations as a solution to avoid these problems, they present some disadvantages which may affect track long-term performance. In this paper, a new solution designed with prefabricated reinforced concrete slabs is proposed. The aim of this solution is to guarantee a continuous and gradual track vertical stiffness transition in the vicinity of structures, overcoming granular wedges disadvantages. The aim of this study is to assess the performance of the novel wedge design by means of a 3-D FEM model and to compare it with the current solution. © 2016, Brazilian Association of Computational Mechanics. All rights reserved. Source

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