This study focuses on the effectiveness of resilient wheels in reducing railway noise and vibrations, and compares the effectiveness of three types of wheels. The finite elements method has been used to characterise the vibratory behaviour of these wheels. The model has been excited with a realistic spectrum of vertical track irregularities, and a spectral analysis has been carried out. Results have been post-processed in order to estímate the sound power emitted. These calculations have been used to assess the effectiveness of the resilient wheel designs in reducing noise emitted to the environment and in propagating structural vibrations.
The current article presents the results of a research study that dealt with the simulation of vehicle -track interaction for a new slab track design, conceived to reduce noise and vibration levels transmitted to the neighbouring buildings. This design is mainly distinguished by its high elasticity and damping. A more elastic track, however, leads to greater rail deflections, which could affect the train's overall running safety. In this study, the derailment risk for trains running on slab track when encountering a broken rail has been evaluated. Two different types of rail fastening system with different elasticities have been analysed and compared. The results of this study will be considered in future track work projects. Up to now, the study has only been applied to straight track, even though the model is currently being extended to also study curved tracks.Numerical methods were used in order to simulate the dynamic behaviour of the train -track interaction. For that purpose, multi-body system (MBS) modelling techniques were combined with the techniques based on the finite-element method (FEM). MBS modelling was used for modelling the vehicle and FEM for simulating the elastic track. The simulation model was validated by comparing simulated results with experimental data obtained in field testing.During the simulations, various safety indices, characteristic of derailment risk, were analysed. The simulations realized at the maximum running velocity of 110 km/h showed a similar behaviour for several track types. When reducing the running speed, the safety indices worsened for both cases. Although the worst behaviour was observed for the track with a greater elasticity, in none of the simulations did a derailment occur when running over the broken rail.
Dynamic analysis using finite elements to calculate the critical wear section of the contact wire in suburban railway overhead conductor rails. Proc. IMechE Part F: Journal of Rail and Rapid Transit, Vol. 222, pp. 145-157, 2008. Dynamic analysis using finite elements to calculate the critical wear section of the contact wire in suburban railway overhead conductor rails F.J. Gonzalez, J.A. Chover, B. Suarez and M. Vazquez The purpose of this study is to determine the critical wear levels of the contact wire of the catenary on metropolitan lines. The study has focussed on the zones of contact wire where localised wear is produced, normally associated with the appearance of electric arcs. To this end, a finite element model has been developed to study the dynamics of pantograph-catenary interaction. The model includes a zone of localised wear and a singularity in the contact wire in order to simulate the worst case scenario from the point of view of stresses. In order to consider the different stages in the wire wear process, different depths and widths of the localised wear zone were defined. The results of the dynamic simulations performed for each stage of wear let the area of the minimum resistant section of the contact wire be determined for which stresses are greater than the allowable stress. The maximum tensile stress reached in the contact wire shows a clear sensitivity to the size of the local wear zone, defined by its width and depth. In this way, if the wear measurements taken with an overhead line recording vehicle are analysed, it will be possible to calculate the potential breakage risk of the wire. A strong dependence of the tensile forces of the contact wire has also been observed. These results will allow priorities to be set for replacing the most critical sections of wire, thereby making maintenance much more efficient. The results obtained show that the wire replacement criteria currently borne in mind have turned out to be appropriate, although in some wear scenarios these criteria could be adjusted even more, and so prolong the life cycle of the contact wire.
The aim of the current paper is to assess the ability of active steering systems to prevent the development of rail corrugation in curves.For that, the corrugation growth rates obtained for a passive vehicle are compared with those obtained for active vehicles (in the current work two strategies for active steering are described and implemented: relative angle control and yaw moment control).The procedure for the calculation of the corrugation growth is described: first the quasi-static creepages produced during curve negotiation are calculated by means of a railway simulator program (SIMPACK) in different cases. Second, these obtained creepages are introduced in a nonlinear corrugation model that evaluates dynamic variations in normal and tangential wheel rail contact forces. Finally, on the basis of these forces, the evolution of the rail profile is determined.The paper includes results of the selected control strategies that show the potentiality of active steering systems in reducing corrugation growth rates.
A mis padres, esposa e hijos. Por supuesto, también tengo que agradecer a Vicent Miguel, Toni, Bernat y Laura por su ayuda y colaboración. De manera especial a Carmen, quien ha sido una gran amiga, con quien vivimos momentos muy entrañables en Valencia. Los resultados derivados de esta Tesis Doctoral pueden ser utilizados el diseño y evaluación de protocolos de comunicación bajo condiciones de propagación próximas a la realidad, así como en el diseño y planificación de las futuras redes vehiculares
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