| 1. |
- Alonso, Asier, et al.
(författare)
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Modelling of rough wheel-rail contact for physical damage calculations
- 2019
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 436
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Tidskriftsartikel (refereegranskat)abstract
- This work presents the initial steps given in order to obtain a comprehensive physical damage model for the specific case of wheel rail contact wear, which would be able to relate contact conditions, material properties and wear rates. The main advantage of a physical damage wear model is that wheelset and rail manufacturers can perform simulations in order to improve and optimise material properties for different operational cases. The work in this paper focuses on delaminative wear, starting with the importance and modelling of rough contact, and a comparison against classic smooth contact models.
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| 2. |
- Alonso, Asier, et al.
(författare)
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Physical damage mechanisms for uniform wear calculation
- 2018
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Ingår i: Proceedings of the 11th International Conference on Contact Mechanics and Wear of Rail/wheel Systems, CM 2018. - Delft, The Netherlands.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This work presents the initial steps given in order to obtain a comprehensive physical model for the specific case of wheel rail contact, which would be able to relate contact conditions, material properties and wear rates. The main advantage of a physical damage wear model is that wheelset an rail manufacturers can perform simulations in order to improve and optimize material properties for different operational cases. The initial work has focused on delaminative wear, starting with the importance and modelling of rough contact, and a comparison against classic smooth contact models.
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| 3. |
- Blanco, Blas, et al.
(författare)
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Assessment of the influence of railway track periodicity, load speed and support modelling on the rolling noise emission
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The presented methodology jointly accounts for the railway track periodicity and the moving load nature at noise predictions. This modelling approaches rail and sleepers employing the Timoshenko beam theory, and it is formulated to be directly implemented into noise software based on irregularity strip technique. By means of precalculated time domain responses with an analytical track model, the periodicity and moving track dynamics are addressed. In the same way, the propagative behaviour in moving conditions of waves along the rail is characterised by comparison of the responses at several positions.Regarding track support modelling, the usual point modelling is substituted by a distributed representation in order to explore the advantages of accounting for the support length. A numerical model fulfils this task and avoids boundary effects utilising infinite elements. Distributed modelling achieves a more realistic representation of the track geometry. It prevents exaggeration of the amplitude at the `pinned-pinned' frequencies without resorting to overestimation of the steel loss factors. This improvement is especially useful when overvalued rail damping leads to predicted track decay rate (TDR) higher than the one experimentally measured.Finally, the impact of periodicity, load speed and support modelling are assessed through the sound power level (SWL) results. The predictions are performed with a software package, CRoNoS (CAF Rolling Noise Software), developed by CAF S.A. Moving conditions has a limited impact on the SWL, while modelling of the foundation as periodic is important at tracks with hard pad types, and distributed support modelling becomes significant when realistic values of the steel loss factor are used.
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| 4. |
- Blanco, Blas, et al.
(författare)
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Modelling of the track supports with elements over elastic foundation together with dynamic internal degrees of freedom
- 2018
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Ingår i: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics2018, Pages 3255-326828th International Conference on Noise and Vibration Engineering, ISMA 2018 and 7th International Conference on Uncertainty in Structural Dynamics, USD 2018; Leuven; Belgium; 17 September 2018 through 19 September 2018. - : KU Leuven - Departement Werktuigkunde. - 9789073802995 ; , s. 3255-3268
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Konferensbidrag (refereegranskat)abstract
- Formulation of the Timoshenko elements is improved with the use of internal degrees of freedom (iDOF) representing the local displacements, leading to a new finite element approach specially devoted to the numeric analysis of the track dynamics. The dynamic formulation of the local displacement is proved to correct the frequency content of the track model. Regarding time domain studies, this approach avoids the displacement underestimation and shear discontinuity between elements, which are sources of inaccuracies and irregular behaviour. Those rail sections located above the supports are modelled with Timoshenko element over elastic foundation (TEEF), and the rest with conventional Timoshenko elements (TIM4). By using TEEF prompt disruption of the contact force at support surpassing is avoided, and the frequency response of the track around the `pinned-pinned' frequency is corrected. Moreover the TEEF formulation is extended in order to account for the sleeper pitch rotation, and evaluation of its influence over the track dynamics is performed.
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| 5. |
- Casanueva, Carlos, 1981-
(författare)
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Análisis dinámico de un eje de ferrocarril con capacidad de cambio de ancho automático
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- El objetivo de la presente tesis es la mejora de los actuales ejes de ancho variable para su circulación por vías de alta velocidad (AV) a velocidades de hasta 300km/h. En la actualidad los vehículos con ejes de ancho variable no sobrepasan los 250km/h de velocidad de servicio en vías de AV, lo que supone un claro desaprovechamiento de recursos y dificultades de gestión del tráfico para el gestor de la infraestructura a causa de las distintas velocidades punta de los diferentes trenes. Los modelos ferroviarios convencionales no tienen en cuenta la flexibilidad asociada a los ejes y suponen que éstos son lo suficientemente rígidos como para no necesitar una modelización que tenga en cuenta su deformación estructural. Sin embargo, en los ejes de ancho variable, que poseen tanto mecanismos que permiten el desplazamiento lateral de rueda respecto al cuerpo de eje como mecanismos de bloqueo de dicho desplazamiento, tienen influencia diversas holguras, rozamiento entre superficies, y componentes intermedios entre ruedas y cuerpo de eje. Estos efectos provocan una flexibilización de la conexión entre ruedas y cuerpo de eje que es necesario estudiar. Por otra parte, en el caso de los ejes de ancho variable de cuerpo de eje no rotativo sus menores solicitaciones a fatiga permiten una importante reducción del diámetro del cuerpo de eje. Esto provoca una flexibilidad adicional muy superior a la de los ejes convencionales. Para el estudio de la influencia de este aumento de flexibilidad en el comportamiento dinámico del eje, en primer lugar se determina qué tipo de modelo permite la correcta representación de los efectos presentes en los análisis dinámicos. Además, se analiza en profundidad el comportamiento del eje de ancho variable, para facilitar el posterior estudio y simplificaciones, así como identificar los componentes críticos del mecanismo. En segundo lugar se calculan las relaciones esfuerzo-deformación para los distintos componentes del sistema: conjunto de rodamientos, cuerpo de eje, mecanismos de anclaje, etc. Dichas características se introducen en un modelo multicuerpo simplificado que es capaz de representar tanto ejes de ancho variable flexibles como ejes convencionales flexibles. Por último se realiza un análisis de la influencia de dichas características en el comportamiento dinámico del vehículo, así como el grado de influencia de cada una de ellas. Además se proponen posibles mejoras del sistema para mejorar sus prestaciones a altas velocidades.
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| 6. |
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| 7. |
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| 8. |
- Casanueva, Carlos, 1981-, et al.
(författare)
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Energy Prediction Benchmark for Universal CostModel Calculations
- 2018
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Konferensbidrag (refereegranskat)abstract
- Within the EU project Roll2Rail a Universal Cost Model (UCM) is being developed that accounts for different costs in the railway system affected by the design of the running gear. The objective of the methodology is not to calculate the global LCC of the entire vehicle (with all its components) but to boost the introduction of new technologies in the bogie by calculating the savings or incremental costs on the LCC that could be obtained between technological alternatives. The UCM will allow a more objective comparison of different bogie concepts, for instance in purchasing processes, and thus it includes a trustworthiness analysis that evaluates how accurate the calculations in the UCM are for a given study.When looking at the total life-cycle cost of a railway vehicle, energy consumption accounts for about 5% of the total expenditure. Within this UCM, a methodology has been proposed that allows the calculation of the energy consumption related to the bogie-technology of any railway vehicle. In order to ensure that all the calculation tools developed by the different partners are adequate, a benchmark simulation has been carried out. The benchmark studies a high-speed vehicle composed of two powered units and four non-powered ones, including six conventional bogies and three Jacobs bogies with both mechanical and ED brakes. In order to validate each simulation tool the share of energy consumed is then compared in different concepts, including in the fields of rolling resistance, curve resistance, unstable running resistance, gradient resistance, aerodynamic and turbulent resistance, inertia resistance and energy use of auxiliary elements. It should be stressed that the comparison and validation focuses on bogie-influenced energy consumption.In this paper, the overall UCM methodology is described, with special focus on the energy calculation methodology. The benchmark case is then presented and the energy calculation of all the partners is compared. A discussion on the calibration of the different partners' calculation tools is carried out, including a follow-updiscussion on the relative importance of the different energy consumption concepts in the final energy expenditure. Finally, the trustworthiness analysis is recalibrated according to these results. Closing remarks aregiven addressing the influence of these costs on the UCM.
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| 9. |
- Casanueva, Carlos, 1981-, et al.
(författare)
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Influence of Bearing Flexibility in Rail Vehicle Dynamics
- 2015
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Ingår i: The international Journal of railway technology. - Edinburgh : Civil-Comp Press. - 2049-5358 .- 2053-602X. ; 4:1, s. 47-67
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Tidskriftsartikel (refereegranskat)abstract
- Dynamic multibody models for railway vehicles usually assume that the stiffness of the bearings is much higher than that of the primary suspension, neglecting their effect whatsoever. This assumption might not be entirely valid for high speed vehicles, where the primary suspension is stiffer than other rail vehicles; or for more complex systems such as variable gauge wheelsets, where the whole mechanic system might have a higher than expected flexibility. In this paper, a model to obtain the stiffness of a typical configuration of railway bearings is developed and applied to both a high speed vehicle bearing set and a variable gauge wheelset bearing set. The results show that the reduction of lateral stiffness as a result of bearing flexibility can reach up to 35% of its theoretical value. This massive reduction has a major influence on the prediction of the dynamic behaviour of these vehicles, e.g. critical speed or curving performance.
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| 10. |
- Casanueva, Carlos, 1981-, et al.
(författare)
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Simple flexible wheelset model for low-frequency instability simulations
- 2014
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Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : Sage Publications. - 0954-4097 .- 2041-3017. ; 228:2, s. 169-181
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Tidskriftsartikel (refereegranskat)abstract
- As a general rule, the multi-body simulation models used by railway vehicle designers consider the wheelsets to be fully rigid, thus leading to possible errors when calculating the critical speed of the vehicle under study. This article suggests a wheelset model that takes into account wheelset flexibility for the study of dynamic stability. The model is simple to implement, easily parameterised, and can be applied to both conventional and variable gauge wheelsets. The parameters corresponding to wheelset flexibility that most influence the critical speed of high-speed and variable gauge vehicles are also analysed.
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