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- Blanco, Blas, 1990-
(författare)
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Railway track dynamic modelling
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The railway vehicles are an increasing mean of transportation due to, its reduced impact on environment and high level of comfort provided. These reasons have contributed to settle a positive perception of railway traffic into the European society. In this upward context, the railway industrial sector tackles some important challenges; maintaining low operational costs and controlling the nuisance by-products of trains operation, the most important being railway noise. Track dynamic plays a main role for both issues, since a significant part of the operational costs are associated with the track maintenance tasks and, the noise generated by the track can be dominant in many operational situations. This explains why prediction tools are highly valued by railway companies. The work presented in this licentiate thesis proposes methodologies for accurate and efficient modelling of railway track dynamics. Two core axes have led the development of this task, on one hand, the rail modelling and, on the other hand, the characterisation of the finite length nature of track supports. Firstly, concerning the rail modelling technique, it has evolved under two major premises. On one hand, regarding the frequency domain, it should describe high frequency behaviour of the rail. In order to accomplish with this first premise, a model based on Timoshenko beam theory is used, which can accurately account for the vertical rail behaviour up to 2500 Hz. On the other hand, with respect to the time domain, the response should be smooth and free of discontinuities. This last condition is fulfilled by implementation of the Timoshenko local deformation. Secondly, a model of support that considers its finite length nature is sought. For this purpose, a Timoshenko element over elastic foundation is formulated. Thus, the common model of support, which is based on a concentrated connection, is substituted by a distributed model of support. In this way, several enhancements are achieved; the temporal contact force response is smoothed and a more realistic shape is obtained, the amplitude of the displacement due to the parametric excitation is reduced and the magnitude associated to the ‘pin-pin’ frequency is not overestimated.
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| 2. |
- Bruni, Stefano, et al.
(författare)
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The results of the pantograph-catenary interaction benchmark
- 2015
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 53:3, s. 412-435
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the results of a voluntary benchmark initiative concerning the simulation of pantograph-catenary interaction, which was proposed and coordinated by Politecnico di Milano and participated by 10 research institutions established in 9 different countries across Europe and Asia. The aims of the benchmark are to assess the dispersion of results on the same simulation study cases, to demonstrate the accuracy of numerical methodologies and simulation models and to identify the best suited modelling approaches to study pantograph-catenary interaction. One static and three dynamic simulation cases were defined for a non-existing but realistic high-speed pantograph-catenary couple. These cases were run using 10 of the major simulation codes presently in use for the study of pantograph-catenary interaction, and the results are presented and critically discussed here. All input data required to run the study cases are also provided, allowing the use of this benchmark as a term of comparison for other simulation codes.
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| 3. |
- Pàlinkò, Márton, 1992-, et al.
(författare)
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Evaluation of passive and mechatronic steering systems for three-axle locomotive bogies by means of multibody simulations
- 2019
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Ingår i: Proceedings of the 11th International conference on railway bogies and running gears.
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Konferensbidrag (refereegranskat)abstract
- In a recent study, concepts were identified and examined that allow heavy-haul locomotive bogies to reduce various wheel and track deterioration in operation. The behaviour of a CoCo Locomotive with passive and active radial steering bogies was evaluated using multibody simulations and compared with the original existing vehicle with rigid axles. The chosen concepts were the following: passive steering using mechanical linkages (EMD), passive hydraulic steering (PHS), active steering using Secondary Yaw Control (SYC), active hydraulic steering (AHS) and self-steering secondary yaw control (SS-SYC).In this analysis, many running conditions were considered, straight track and curves down to 250 m radius with track irregularities according to the standard DIN EN 14363 [1]. Various non-compensated lateral accelerations and presumed friction levels were chosen as input parameters to cover a wide range of operating conditions in order to estimate the benefits of these solutions over the life cycle of the vehicle. As it is a locomotive, traction was also included in some simulation scenarios.A comparative assessment of the track-friendliness was performed, considering a variety of track layouts (represented by diverse mixes of straight track sections and curved track sections with different curvatures) and operation scenarios. Track loading was assessed considering four performance indexes: track component fatigue, track settlement, rail/wheel wear and RCF accumulation.The investigation evinced significant reduction of wheel/rail wear especially for the EMD, AHS and SS-SYC concepts. Due to reduced primary suspension stiffness, the EMD, PHS and SS-SYC solutions provide lower track component fatigue. The presence of traction increases wear and RCF, but the EMD, AHS and SS-SYC bogies still provide significant benefits compared to the original locomotive.
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