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On Rail Vehicle Dynamics in Unsteady Crosswind Conditions: Studies Related to Modelling, Model Validation and Active Suspension
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Crosswind stability of rail vehicles has been a research area for several decades, mainlymotivated by vehicle overturning accidents and higher speeds, but in recent times also byissues of lower energy consumption and track maintenance costs demanding lower vehi-cle weights. During everyday operation, rail vehicles are subjected to substantial lateralinfluences from track curves, track irregularities and crosswind, leading to large suspen-sion deflections and increased crosswind sensitivity. Unsteady crosswind like gusts alsocalls for attention. Simulations of possible vehicle overturning are necessary, but needto take large deflections and high shear in the suspension into account. If they deliverreasonable results, simulations represent an important tool for overturning predictionof rail vehicles.In the present work, multibody simulations of a high-speed rail vehicle under large lat-eral influences from track curves and track irregularities have been carried out, using ahalf-vehicle model in 2D and a full vehicle model in 3D, including different suspensionmodels. Corresponding field measurements of the relative lateral and vertical deflec-tions in the secondary suspension were performed on a fast train and used to validatethe multibody simulations.The 3D vehicle model was further used to study the vehicle response to unsteady cross-wind during curve negotiation, including aerodynamic loads obtained from unsteadyComputational Fluid Dynamics. In addition, the Quasi Transient Gust Modelling methodwas evaluated. Strong lateral and roll responses of the vehicle and influences of the gustduration and the relative difference between mean and maximum wind speed were ob-served. The influence of the vehicle’s suspension and mass properties on crosswindsensitivity were studied in addition.In order to validate modelling and simulation results for gust-like loads on a rail vehi-cle, full-scale experiments were conducted by exciting the carbody of a stationary railvehicle, imitating synchronous and asynchronous crosswind-like loads and measuringthe vehicle response. The measurements were reflected in multibody simulations, whichwere in good agreement with the measured responses. Parameter studies of the suspen-sion characteristics were performed additionally. Asynchronous crosswind-like loadswere in comparison to synchronous loads observed to result in lower wheel-unloadingIt was further studied whether active secondary suspension can be used to improve cross-wind stability. A fast rail vehicle equipped with active secondary suspension for ridecomfort purposes is exposed to crosswind loads during curve negotiation by means ofsimulations. For high crosswind loads, the active suspension is used to reduce the impactof crosswind on the vehicle. The control input is taken from the primary vertical sus-pension deflection. Three different control cases were studied and compared to the onlycomfort-oriented active secondary suspension and a passive secondary suspension. The application of active suspension resulted in significantly improved crosswind stability.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2013. , xvi, 48 p.
Series
Trita-AVE, ISSN 1651-7660 ; 2013:61
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Fordonsteknik
Identifiers
URN: urn:nbn:se:kth:diva-133723ISBN: 978-91-7501-914-7 (print)OAI: oai:DiVA.org:kth-133723DiVA: diva2:663404
Public defence
2013-11-28, E3, Osquarsbacke 14, KTH, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

QC 20131111

Available from: 2013-11-11 Created: 2013-11-08 Last updated: 2013-11-11Bibliographically approved
List of papers
1. Measurements and simulations of rail vehicle dynamics with respect to overturning risk
Open this publication in new window or tab >>Measurements and simulations of rail vehicle dynamics with respect to overturning risk
2010 (English)In: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 48, no 1, 97-112 p.Article in journal (Refereed) Published
Abstract [en]

Rail vehicles are exposed to strong lateral influences through curves, track imperfections andcrosswind leading to large deflections of the vehicle suspension systems and carbody displacements.In turn this increases the risk of vehicle overturning. In the present work multibodysimulations are performed in order to study the motion in the secondary suspension. Suspensiondeflection measurements on a fast test train were carried out and used for validation ofthe simulations. The simulations show good agreement with the measurements and representa good tool to predict the motion in the secondary suspension.

Place, publisher, year, edition, pages
Milton Park: Taylor & Francis, 2010
Keyword
Rail vehicle dynamics, overturning risk, crosswind, suspension modelling, multibody simulations, field measurements
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Fordonsteknik
Identifiers
urn:nbn:se:kth:diva-11374 (URN)10.1080/00423110903243216 (DOI)000277739200007 ()2-s2.0-77949530641 (Scopus ID)
Note

22nd International Congress of Theoretical and Applied Mechanics, Adelaide, AUSTRALIA, AUG 24-29, 2008. QC 20150630

Available from: 2009-11-02 Created: 2009-11-02 Last updated: 2017-12-12Bibliographically approved
2. Dynamics of a high-speed rail vehicle negotiating curves at unsteady crosswind
Open this publication in new window or tab >>Dynamics of a high-speed rail vehicle negotiating curves at unsteady crosswind
2010 (English)In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 224, no F6, 567-579 p.Article in journal (Refereed) Published
Abstract [en]

Rail vehicles in everyday operation experience large lateral influences from curves and track imperfections, yielding large suspension deflections and displacements of the carbody relative to the track. Aerodynamic loads caused by crosswind may deteriorate the conditions that can result in vehicle overturning. This study investigates the influence of crosswind on a highspeed rail vehicle negotiating a curve. A multi-body simulation model of a high-speed rail vehicle is subjected to unsteady aerodynamic loads. The vehicle response is studied for different gusts, and variations of some vehicle parameters are performed.

Place, publisher, year, edition, pages
London: Professional Engineering Publishing, 2010
Keyword
Rail vehicle dynamics, crosswind stability, overturning risk, unsteady aerodynamics, multibody simulations, CFD, computational fluid dynamics
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Fordonsteknik
Identifiers
urn:nbn:se:kth:diva-11376 (URN)10.1243/09544097JRRT335 (DOI)000284103500006 ()2-s2.0-78349250908 (Scopus ID)
Note
QC 20101102. Uppdaterad från accepted till published (20101213).Available from: 2009-11-02 Created: 2009-11-02 Last updated: 2017-12-12Bibliographically approved
3. Rail vehicle response to lateral carbody excitations imitating crosswind
Open this publication in new window or tab >>Rail vehicle response to lateral carbody excitations imitating crosswind
2015 (English)In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 229, no 1, 34-47 p.Article in journal (Refereed) Published
Abstract [en]

Repeatable field tests to measure the vehicle response to unsteady crosswinds are not practical due to safety and economic reasons. Simulations are therefore necessary to gather information on the vehicle response to crosswind. However, in turn, these simulations need to be validated. This study presents results of measured quasi-static and dynamic responses of a stationary rail vehicle due to defined lateral carbody excitations imitating unsteady crosswind, which are reflected by multibody simulations. The vehicle responses are measured in terms of suspension deflections, lateral carbody accelerations and vertical wheel/rail forces. The vehicle dynamic response to a gust-like event results in an overshoot of wheel unloading. In general the measurements and simulations show good agreement. However, the simulations partly overestimate the responses slightly and an influence due to airspring levelling can be observed in the measured values of quasi-static load cases.

Keyword
Rail vehicle dynamics, Crosswind, Full-scale measurements, Multibody simulations
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Fordonsteknik
Identifiers
urn:nbn:se:kth:diva-133721 (URN)10.1177/0954409713496765 (DOI)000346644200004 ()2-s2.0-84919458803 (Scopus ID)
Funder
Vinnova
Note

QC 20150122

Available from: 2013-11-08 Created: 2013-11-08 Last updated: 2017-12-06Bibliographically approved
4. Improving crosswind stability of fast rail vehicles using active secondary suspension
Open this publication in new window or tab >>Improving crosswind stability of fast rail vehicles using active secondary suspension
2014 (English)In: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 52, no 7, 909-921 p.Article in journal (Refereed) Published
Abstract [en]

Rail vehicles are today increasingly equipped with active suspension systems for ride comfort purposes. In this paper, it is studied whether these often powerful systems also can be used to improve crosswind stability. A fast rail vehicle equipped with active secondary suspension for ride comfort purposes is exposed to crosswind loads during curve negotiation. For high crosswind loads, the active secondary suspension is used to reduce the impact of crosswind on the vehicle. The control input is taken from the primary vertical suspension deflection. Three different control cases are studied and compared with the only comfort-oriented active secondary suspension and a passive secondary suspension. The application of active secondary suspension resulted in significantly improved crosswind stability.

Keyword
rail vehicle dynamics, crosswind stability, unsteady crosswind, active suspension, multi-body simulations
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:kth:diva-133722 (URN)10.1080/00423114.2014.909092 (DOI)000338990600003 ()2-s2.0-84903758704 (Scopus ID)
Note

QC 20140818. Updated from submitted to published.

Available from: 2013-11-08 Created: 2013-11-08 Last updated: 2017-12-06Bibliographically approved

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