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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.


Reala J.I.,Polytechnic University of Valencia | Galisteoa A.,Polytechnic University of Valencia | Realb T.,University of Alicante | Zamoranoc C.,Foundation for the Research and Engineering in Railways
Journal of Vibroengineering | Year: 2012

Nowadays, the consolidation of the rail in highly populated areas has become a reality. Foundations, buildings, high accuracy devices and people are susceptible to suffer from vibrations induced by passing trains. Therefore, models for predicting ground vibrations are required in order to determine new mitigation measures. Rectangular open or in-filled trenches are a suitable solution to be used near constructed railway lines. Their installation is fast, easy and economic since no intrusion in the track is needed. In this work, the influence of the trench design on its effectiveness is analyzed considering a train moving with subsonic speed. A finite element model of the track has been developed and validated with real data registered along the tram network in Alicante (Spain). The analysis is carried out in the time domain considering the quasi-static movement of the vehicles. The results demonstrate that, in ascending order, the most relevant parameters in a trench are its width, depth and in-filled material or trench typology. However, it is also concluded that other conditions such as the stratification of soil are essential in order to determine an optimal design of a wave barrier. © VIBROENGINEERING.


Real J.I.,Polytechnic University of Valencia | Asensio T.,Polytechnic University of Valencia | Montalban L.,Polytechnic University of Valencia | Zamorano C.,Foundation for the Research and Engineering in Railways
Journal of Vibroengineering | Year: 2012

Vibrations generated by trains and transmitted to the ground and nearby structures are a known source of problems associated with railway transport. Therefore this phenomenon should be studied in detail to avoid a negative impact on the environment. Within this framework, the article develops an improved version of a previously published analytical model capable of predicting ground vibrations caused by the passing railway vehicles. The new features include a new formulation of the models with five layers of material and an enhanced load input process that takes into account actual rail defects data as well as the Hertz theory for the rail-wheel contact. The model is adapted to a conventional ballasted track in Solares (Spain) as well as calibrated and validated with data collected on site. Hence the model is proved to be able to properly reproduce vibrations for the case of varying track typologies, constituting a useful research and design tool. © VIBROENGINEERING. JOURNAL OF VIBROENGINEERING.


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.


Real J.I.,Polytechnic University of Valencia | Sanchez M.E.,Polytechnic University of Valencia | Real T.,University of Alicante | Sanchez F.J.,3C Apolonio Morales | Zamorano C.,Foundation for the Research and Engineering in Railways
Structural Engineering and Mechanics | Year: 2012

Concrete sleepers are essential components of the conventional railway. As support elements, sleepers are always subjective to a variety of time-dependent loads attributable to the train operations, either wheel or rail abnormalities. It has been observed that the sleepers may deteriorate due to these loads, inducing the formation of hairline cracks. There are two areas along the sleepers that are more prone to crack: the central and the rail seat sections. Several non-destructive methods have been developed to identify failures in structures. Health monitoring techniques are based on vibration responses measurements, which help engineers to identify the vibration-based damage or remotely monitor the sleeper health. In the present paper, the dynamic effects of the cracks in the vibration signatures of the railway pre-stressed concrete sleepers are investigated. The experimental modal analysis has been used to evaluate the modal bending changes in the vibration characteristics of the sleepers, differentiating between the central and the rail seat locations of the cracks. Modal parameters changes of the 'healthy' and cracked sleepers have been highlighted in terms of natural frequencies and modal damping. The paper concludes with a discussion of the most suitable failure indicator and it defines the vibration signatures of intact, central cracked and rail seat cracked sleepers.


Real T.,Polytechnic University of Valencia | Zamorano C.,Foundation for the Research and Engineering in Railways | Ribes F.,Polytechnic University of Valencia | Real J.I.,Polytechnic University of Valencia
Tunnelling and Underground Space Technology | Year: 2015

The purpose of this study is to develop a 3D numerical FEM model of a railway tunnel to predict railway induced vibrations, which is calibrated and validated with in situ measurements. After that, two different 2D FEM models are constructed following the same assumptions as in the 3D model but different methodologies to introduce the loads. The results from the different models are used to determine the existing differences among each type of model, and the scope of each one. Vertical accelerations are obtained from each model and compared among them, concluding that the 3D FEM models provide more accurate results with a longer calculation time and require huge computational requirements. © 2015 Elsevier Ltd.


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).


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.


Real J.I.,Polytechnic University of Valencia | Zamorano C.,Foundation for the Research and Engineering in Railways | Hernandez C.,Polytechnic University of Valencia | Comendador R.,University of Alicante | Real T.,Polytechnic University of Valencia
Journal of Vibroengineering | Year: 2014

The study of vibrations induced by a passing train is of utmost importance to understand better this phenomenon and to design efficient mitigation measures. Within all the techniques used to model vibrations, finite element methods allow introducing in the model detailed characteristics of the real vehicle-train-soil system. However, the accuracy of the results is linked to how detailed the real elements implemented in the model are and consequently, with the computing time. In this paper a three-dimensional finite element method to predict vibrations is developed and validated with real field-measured data. Then, different scenarios are represented to assess the efficiency of the model linking the quality of the results obtained with the calculation time required in each case. Finally, a reflection regarding the constitutive model of the materials when working with finite element models is done. © JVE INTERNATIONAL LTD. JOURNAL OF VIBROENGINEERING. JUNE 2014.


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.

Loading Foundation for the Research and Engineering in Railways collaborators
Loading Foundation for the Research and Engineering in Railways collaborators