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Non-Elliptic Wheel-Rail Contact Modelling in Vehicle Dynamics Simulation
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.ORCID iD: 0000-0003-2590-3698
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. Bombardier Transportation, Sweden.ORCID iD: 0000-0002-3447-6686
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.ORCID iD: 0000-0002-2571-4662
2014 (English)In: The international Journal of railway technology, ISSN 2049-5358, E-ISSN 2053-602X, Vol. 3, no 3, 77-94 p.Article in journal (Refereed) Published
Abstract [en]

An approximate rolling contact model is introduced for fast evaluation of the contactpatch and stress distribution in the wheel-rail interface, capable of being usedon-line with dynamics simulations. The normal part of the model is based on a novelapproach in which the surface deformations are approximated, resulting in accuratepatch and pressure estimation. The tangential part is based on an adaptation of FASTSIMalgorithm to non-elliptic patches. The new model is compared to the approximatemodel of Kik and Piotrowski and the results are evaluated using Kalker’s CONTACTcode. The comparison clearly shows that the new model is more accurate than Kikand Piotrowski’s in terms of contact patch and stress distribution as well as creepforce estimation.

Place, publisher, year, edition, pages
2014. Vol. 3, no 3, 77-94 p.
National Category
Vehicle Engineering
URN: urn:nbn:se:kth:diva-181013OAI: diva2:897776

QC 20160202

Available from: 2016-01-26 Created: 2016-01-26 Last updated: 2016-02-02Bibliographically approved
In thesis
1. On Efficient Modelling of Wheel-Rail Contact in Vehicle Dynamics Simulation
Open this publication in new window or tab >>On Efficient Modelling of Wheel-Rail Contact in Vehicle Dynamics Simulation
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The wheel-rail contact is at the core of all research related to vehicletrackinteraction. This tiny interface governs the dynamic performanceof rail vehicles through the forces it transmits and, like any high stressconcentration zone, it is subjected to serious damage phenomena. Thus,a clear understanding of the rolling contact between wheel and rail is keyto realistic vehicle dynamics simulation and damage analysis.

In a multi-body dynamics simulation, the demanding contact problemshould be evaluated at about every millisecond for several wheel-rail pairs.Hence, a rigorous treatment of the contact is highly time-consuming.Simplifying assumptions are therefore made to accelerate the simulationprocess. This gives rise to a trade-o between the accuracy and computationaleciency of the contact model in use.

Conventionally, Hertz+FASTSIM is used for calculation of the contactforces thanks to its low computational cost. However, the elliptic patchand pressure distribution obtained by Hertz' theory is often not realisticin wheel-rail contact. Moreover, the use of parabolic traction bound inFASTSIM causes considerable error in the tangential stress estimation.This combination leads to inaccurate damage predictions.

Fast non-elliptic contact models are proposed by others to tacklethis issue while avoiding the tedious numerical procedures. The studiesconducted in the present work show that the accuracy of these models iscase-dependent.

To improve the accuracy of non-elliptic patch and pressure estimation,a new method is proposed. The method is implemented in an algorithmnamed ANALYN. Comparisons show improvements in patch and, particularly,pressure estimations using ANALYN.

In addition, an alternative to the widely-used FASTSIM is developed, named FaStrip. Unlike FASTSIM, it employs an elliptic traction boundand is able to estimate the non-linear characteristic of tangential stressdistribution. Comparisons show more accurate estimation of tangentialstress and slip velocity distribution as well as creep forces with FaStrip.

Ultimately, an ecient non-elliptic wheel-rail contact model consistingof ANALYN and FaStrip is proposed. The reasonable computationalcost of the model enables it to be used on-line in dynamics simulationand its accuracy can improve the damage predictions.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2016. xiv, 97 p.
TRITA-AVE, ISSN 1651-7660 ; 2016:02
wheel-rail contact, non-elliptic contact, rail vehicle dynamics, rolling contact, vehicle-track interaction, wheel-rail damage
National Category
Vehicle Engineering Tribology
Research subject
Järnvägsgruppen - Fordonsteknik; The KTH Railway Group - Tribology; Vehicle and Maritime Engineering
urn:nbn:se:kth:diva-181691 (URN)978-91-7595-846-0 (ISBN)
Public defence
2016-02-24, F3, Lindstedsvägen 26, KTH, Stockholm, 13:15 (English)

QC 20160202

Available from: 2016-02-02 Created: 2016-02-02 Last updated: 2016-02-02Bibliographically approved

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