Influence of creep forces on the risk of derailment of railway vehicles

Santamaría, Javier; Vadillo, E.G.; Gómez, Jorge Fernández

doi:10.1080/00423110802368817

Cited by 35 publications

(27 citation statements)

References 26 publications

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“…The wheel's flange also plays a major role in terms of running safety. Both the flange angle and the total thickness are parameters which exercise a decisive influence on running safety [20]. The profile is therefore left with the same shape as the original wheel as of the straight section at 70º, thus retaining the properties of the original wheel against the risk of derailment.…”

Section: Definition Of the Optimisation Variablesmentioning

confidence: 99%

Design of an optimised wheel profile for rail vehicles operating on two-track gauges

Santamaría

Herreros

Vadillo

et al. 2013

Vehicle System Dynamics

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Please cite this paper as: Santamaria, J., Herreros, J., Vadillo, E.G., Correa, N. Design of an optimised wheel profile for rail vehicles operating on two track gauges.Vehicle System Dynamics, Vol. 51, This paper sets out an optimum synthesis methodology for wheel profiles of railway vehicles in order to secure good dynamic behaviour with different track configurations. Specifically, the optimisation process has been applied to the case of rail wheelsets mounted on double gauge bogies, that move over two different gauges, which also have different types of rail: the Iberian gauge (1668 mm) and the UIC gauge (1435 mm). Optimisation is performed using Genetic Algorithms and traditional optimisation methods in a complementary way. The objective function used is based on an ideal equivalent conicity curve which ensures good stability on straight sections and also proper negotiation of curves. To this end the curve is constructed in such a way that it is constant with a low value for small lateral wheelset displacements (with regard to stability), and increases as the displacements increase (to facilitate negotiation of curved sections). Using this kind of ideal conicity curve also enables a wheel profile to be secured where the contact points have a larger distribution over the active contact areas, making wear more homogeneous and reducing stresses. The result is a wheel profile with a conicity that is closer to the target conicity for both gauges studied, producing better curve negotiation while maintaining good stability on straight sections of track. The paper shows the resultant wheel profile, the contact curves it produces, and a number of dynamic analyses demonstrating better dynamic behaviour of the synthesised wheel on curved sections with respect to the original wheel.

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Section: Definition Of the Optimisation Variablesmentioning

confidence: 99%

Design of an optimised wheel profile for rail vehicles operating on two-track gauges

Santamaría

Herreros

Vadillo

et al. 2013

Vehicle System Dynamics

Self Cite

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“…They are mainly connected with the reduction of costs of maintenance, technical diagnostics of the track and of railway vehicles, and elimination of negative effects on the environment. Many of the works have been related to the increase in train speed of railway vehicles without affecting safety and comfort [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Modeling of Energy Processes in Wheel-Rail Contacts Operating under Influence of Periodic Discontinuous Forces

Trzaska¹

2012

JTTs

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In this paper we present new numerical simulation approaches for determining the energy processes under periodic conditions caused by time-discontinuous forces in the wheel-rail contacts. The main advantage of the presented method is the total elimination of frequency analysis, which in effect introduces important simplifications in the identification of the effects in the contact. The second important feature is the fact that the method is based on the analysis of appropriate loops on the energy phase plane leading to an easy estimation of the rail strength through the evaluation of the loop's area. That model based simulation in the applied dynamics relies on advanced methods for model setup, robust and efficient numerical solution techniques and powerful simulation tools for practical applications. Fundamental properties of contact displacements of the rail surface have been considered on the basis of the newly established method. The contact zone between railway wheels and the rail surfaces made of bulk materials is perceived as strong enough to resist the normal (vertical) forces introduced by heavy loads and the dynamic response induced by track and wheel irregularities. The analysis is carried out for a wheel running on an elastic rail rested on sleepers arranged on completely rigid foundation. The equations of displacement motion are established through the application of the Lagrange equations approach. The established model of the wheel-rail contact dynamics has been applied to that same roll plane but with taking into account a nonlinear characteristic of the sleeper with respect to the ground. Attention then is focused completely on the modeling of the energy absorbed by the rail. The applied method employs the energy state variables as time functions leading to determine the susceptibility of a given contact on the strength induced by the rail roll.

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“…in [5][6][7][8][9] have shown both experimentally and by means of mathematical modelling and simulation that the limit value for the derailment coefficient is also affected by other parameters, such as the angle of attack of the wheel over the rail and the ratio between the vertical forces on the flanging and non-flanging wheels. Furthermore, this limit value also depends upon the magnitude of the longitudinal force acting at wheel-rail contact.…”

Section: Derailment Criteriamentioning

confidence: 99%

“…Hence, the derailment criterion best suited to describe the wheelset's proneness to derailment can be different depending on the specific design concept. It is also worth pointing out that the derailment criteria introduced in ref.s [6][7][8][9][10][11] are all based on the consideration of the flange-climb process as a quasi-static one, whereas in many cases derailment occurs as the consequence of violent shocks produced by local track defects. More research might be needed to assess the validity of the above criteria in dynamic conditions and/or to propose new criteria considering in full the dynamics of the wheelset.…”

Section: Derailment Criteriamentioning

confidence: 99%

See 1 more Smart Citation

A Study of the Factors Affecting Flange-Climb Derailment in Railway Vehicles

Diana¹,

Bruni²,

Gialleonardo³

et al.

Proceedings of the Third International Conference on Railway Technology: Research, Development and Maintenance

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Avoiding flange climb derailment is one main issue with ensuring the running safety of railway vehicles. This paper discusses the different causes that can lead to the derailment of a railway wheel, particularly in the light of different derailment criteria used by the standards or proposed by various researchers.Furthermore the paper presents two case studies, one for a vehicle with solid axles and one for a bogie with independently rotating wheels, reporting a description of the derailment case and discussing the causes that led to derailment, by making combined use of measurements and numerical simulation.Based on these exemplary cases, some conclusions are drawn concerning the validity of the derailment criteria presently used by the standards in force.

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Influence of creep forces on the risk of derailment of railway vehicles

Cited by 35 publications

References 26 publications

Design of an optimised wheel profile for rail vehicles operating on two-track gauges

Design of an optimised wheel profile for rail vehicles operating on two-track gauges

Modeling of Energy Processes in Wheel-Rail Contacts Operating under Influence of Periodic Discontinuous Forces

A Study of the Factors Affecting Flange-Climb Derailment in Railway Vehicles

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