The effect of the fastener's failure in a railway track on the dynamic forces produced in the wheel-rail contact is studied using the simulation software VAMPIRE to assess the derailment risk of two different vehicles in two curves with distinct characteristics. First, a 3D-FEM model of a real track is constructed, paying special attention to fasteners, and calibrated with displacement data obtained experimentally during a train passage. This numerical model is subsequently used to determine the track vertical and lateral stiffness. This study evidences that although the track can practically lose its lateral stiffness as a consequence of the failure of 7 consecutive fasteners, the vehicle stability would not be necessarily compromised in the flawed zone. Moreover, the results reveal that the uncompensated acceleration and the distance along which the fasteners are failed play an important role in the dynamic behavior of the vehicle-track system, influencing strongly the risk of derailment.
Abrupt variations of track stiffness in transitions from conventional to slab track, e.g., over bridges and tunnels, usually lead to passenger discomfort, vehicle and track damage and even safety issues. Therefore, to minimize this negative effect, it is very convenient to smooth the stiffness changes in such transitions; and wedges arise as a very effective technique. Although granular wedges are commonly suggested by railroad managers as a solution, this typology presents some disadvantages, e.g., high construction time and costs, that should be addressed. In this paper, a new solution based on prefabricated, reinforced concrete slabs is presented and its dynamical performance is assessed by means of a 3D FEM model. Results indicate that track vibrations both on the rail and over a sleeper are considerably reduced when the new slab-based wedge is considered instead of a traditional granular wedge.
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.
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.
Original papers containing developments in vibroengineering of dynamical systems (macro-, micro-, nano-mechanical, mechatronic, biomechanics and etc. systems).The following subjects are principal topics: Vibration and wave processes; Vibration and wave technologies; Nonlinear vibrations; Vibroshock systems; Generation of vibrations and waves; Vibrostabilization; Transformation of motion by vibrations and waves; Dynamics of intelligent mechanical systems; Vibration control, identification, diagnostics and monitoring.All published papers are peer reviewed. General RequirementsThe authors must ensure that the paper presents an original unpublished work which is not under consideration for publication elsewhere.The following structure of the manuscript is recommended: abstract, keywords, nomenclature, introduction, main text, results, conclusions and references. Manuscript should be single-spaced, one column 162×240 mm format, using Microsoft Word 2007 or higher. Margins Figure caption starts with figure number 9 pt Bold as " Fig. 1 DAMAGE DETECTION OF PIPELINE MULTIPLE CRACKS USING PIEZOCERAMIC TRANSDUCERS 2828GUOFENG DU, LINSHENG HUO, QINGZHAO KONG, GANGBING SONG Received 6 October 2015; received in revised form 27 December 2015; accepted 22 April 2016 DOI http://dx.doi.org/10.21595/jve.2016 Abstract. Resonance is a phenomenon of utmost importance in railways engineering, leading to vast damages both in track and vehicles. Thus, to avoid the undesired effect of resonance, it must be studied, understood and predicted. To this aim, in the current study a FE model able to reproduce the dynamic behavior of a real stretch of track has been developed and its correct behavior has been calibrated with real data. Furthermore, different measures of mitigation have been proposed and its effect on displacements and vibrations in the mid-span section of a railway bridge have been evaluated. INELASTIC PARAMETRIC ANALYSIS OF FREQUENCIES AND SEISMIC RESPONSES OF SOIL-MULTISTOREY BIDIRECTIONAL ECCENTRIC STRUCTURE INTERACTION SYSTEM 3010 XIN-LIANG JIANG, YU-PING KUANG, NAN JIANG A U T H O R ' S P E R S O N A L C O P Y A U T H O R ' S P E R S O N A L C O P Y
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