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  • 151.
    Sh. Sichani, Matin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Järnvägsteknik. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Enblom, Roger
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Järnvägsteknik. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Järnvägsteknik. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Comparison of non-elliptic contact models: Towards fast and accurate modelling of wheel-rail contact2014Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 314, nr 1-2, s. 111-117Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The demand to investigate and predict the surface deterioration phenomena in the wheel-rail interface necessitates fast and accurate contact modelling. During the past 20 years, there have been attempts to determine more realistic contact patch and stress distributions using fast simplified methods. The main aim of the present work is to compare some of these state-of-the-art, non-elliptic contact models available in the literature. This is considered as the first step to develop a fast and accurate non-elliptic contact model that can be used on-line with vehicle dynamics analysis. Three contact models, namely STRIPES, Kik-Piotrowski and Linder are implemented and compared in terms of contact patch prediction, as well as contact pressure and traction distributions. The evaluation of these models using CONTACT software indicate the need for improvement of contact patch and pressure estimation in certain contact cases.

  • 152.
    Shahzamanian Sichani, Matin
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    On Efficient Modelling of Wheel-Rail Contact in Vehicle Dynamics Simulation2016Doktoravhandling, med artikler (Annet vitenskapelig)
    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.

  • 153.
    Shahzamanian Sichani, Matin
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Wheel-rail contact modelling in vehicle dynamics simulation2013Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The wheel-rail contact is at the core of all research related to vehicle-track interaction. This tiny interface governs the dynamic performance of rail vehicles through the loads it transmits and, like any high stress concentration zone, it is subjected to serious damage phenomena. Thus, a clear understanding of the rolling contact between wheel and rail is key to realistic vehicle dynamic simulation and damage analyses.

    In a multi-body-system simulation package, the essentially demanding contact problem should be evaluated in about every millisecond. Hence, a rigorous treatment of the contact is highly time consuming. Simplifying assumptions are, therefore, made to accelerate the simulation process. This gives rise to a trade-off between accuracy and computational efficiency of the contact models in use.

    Historically, Hertz contact solution is used since it is of closed-form. However, some of its underlying assumptions may be violated quite often in wheel-rail contact. The assumption of constant relative curvature which leads to an elliptic contact patch is of this kind. Fast non-elliptic contact models are proposed by others to lift this assumption while avoiding the tedious numerical procedures. These models are accompanied by a simplified approach to treat tangential tractions arising from creepages and spin.

    In this thesis, in addition to a literature survey presented, three of these fast non-elliptic contact models are evaluated and compared to each other in terms of contact patch, pressure and traction distributions as well as the creep forces. Based on the conclusions drawn from this evaluation, a new method is proposed which results in more accurate contact patch and pressure distribution estimation while maintaining the same computational efficiency. The experience gained through this Licentiate work illuminates future research directions among which, improving tangential contact results and treating conformal contacts are given higher priority.

  • 154.
    Shahzamanian Sichani, Matin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Enblom, Roger
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. Bombardier Transportation, Sweden.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    A Fast Wheel-Rail Contact Model for Detailed Damage Analysis in Dynamics SimulationManuskript (preprint) (Annet vitenskapelig)
  • 155.
    Shahzamanian Sichani, Matin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Enblom, Roger
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. Bombardier Transportation, Sweden .
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    A novel method to model wheel-rail normal contact in vehicle dynamics simulation2014Inngår i: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 52, nr 12, s. 1752-1764Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An approximate analytical method is proposed for calculating the contact patch and pressure distribution in the wheel-rail interface. The deformation of the surfaces in contact is approximated using the separation between them. This makes it possible to estimate the contact patch analytically. The contact pressure distribution in the rolling direction is assumed to be elliptic with its maximum calculated by applying Hertz' solution locally. The results are identical to Hertz's for elliptic cases. In non-elliptic cases good agreement is achieved in comparison to the more accurate but computationally expensive Kalker's variational method (CONTACT code). Compared to simplified non-elliptic contact methods based on virtual penetration, the calculated contact patch and pressure distribution are markedly improved. The computational cost of the proposed method is significantly lower than the more detailed methods, making it worthwhile to be applied to rolling contact in rail vehicle dynamics simulation. Such fast and accurate estimation of contact patch and pressure paves the way for on-line modelling of damage phenomena in dynamics simulation packages.

  • 156.
    Shahzamanian Sichani, Matin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Enblom, Roger
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg. Bombardier Transportation, Sweden.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    An alternative to FASTSIM for tangential solution of the wheel–rail contact2016Inngår i: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 54, nr 6, s. 748-764Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In most rail vehicle dynamics simulation packages, tangential solution of the wheel–rail contact is gained by means of Kalker's FASTSIM algorithm. While 5–25% error is expected for creep force estimation, the errors of shear stress distribution, needed for wheel–rail damage analysis, may rise above 30% due to the parabolic traction bound. Therefore, a novel algorithm named FaStrip is proposed as an alternative to FASTSIM. It is based on the strip theory which extends the two-dimensional rolling contact solution to three-dimensional contacts. To form FaStrip, the original strip theory is amended to obtain accurate estimations for any contact ellipse size and it is combined by a numerical algorithm to handle spin. The comparison between the two algorithms shows that using FaStrip improves the accuracy of the estimated shear stress distribution and the creep force estimation in all studied cases. In combined lateral creepage and spin cases, for instance, the error in force estimation reduces from 18% to less than 2%. The estimation of the slip velocities in the slip zone, needed for wear analysis, is also studied. Since FaStrip is as fast as FASTSIM, it can be an alternative for tangential solution of the wheel–rail contact in simulation packages.

  • 157.
    Shahzamanian Sichani, Matin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Enblom, Roger
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. Bombardier Transportation, Sweden.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    An Alternative to FASTSIM for Tangential Solution of the Wheel-Rail ContactManuskript (preprint) (Annet vitenskapelig)
  • 158.
    Shahzamanian Sichani, Matin
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Enblom, Roger
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. Bombardier Transportation, Sweden.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Non-Elliptic Wheel-Rail Contact Modelling in Vehicle Dynamics Simulation2014Inngår i: The international Journal of railway technology, ISSN 2049-5358, E-ISSN 2053-602X, Vol. 3, nr 3, s. 77-94Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 159.
    Sichani, Matin Sh.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Enblom, Roger
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. Bombardier Transportation, Sweden.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    A fast wheel-rail contact model for application to damage analysis in vehicle dynamics simulation2016Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 366, s. 123-130Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel wheel-rail contact model is proposed to be implemented for multi-body dynamics simulation, in order to facilitate accurate online calculation of damage phenomena such as wear and rolling contact fatigue. The normal contact, i.e. contact patch and pressure distribution, is calculated using a fast non elliptic algorithm called ANALYN. The tangential contact, i.e. tangential stress distribution, stick-slip division and creep force calculation, is treated using an alternative to the FASTSIM algorithm that is based on a strip theory which extends the two-dimensional solution of rolling contact to three-dimensional contacts. The proposed contact model is compared to the Hertz+FASTSIM model and evaluated using the CONTACT code in terms of contact patch and stress distribution as well as creep force curves. The results show that the proposed model can significantly improve the estimation of the contact solution both in terms of creep force estimation and contact details, such as stress distribution, needed for damage predictions.

  • 160.
    Sichani, Matin Shahzamanian
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Enblom, Roger
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. Bombardier Transportation, Specialist Engineering Department, Västerås, Sweden.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Wheel-rail contact modeling for damage predictions in dynamics simulation software2015Inngår i: CM 2015 - 10th International Conference on Contact Mechanics of Wheel / Rail Systems, International Conference on Contact Mechanics of Wheel , 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A novel wheel-rail contact model is proposed to be implemented for multi-body dynamics simulation, in order to facilitate accurate online calculation of damage phenomena such as wear and rolling contact fatigue. The normal contact, i.e. contact patch and pressure distribution, is calculated using a fast non-elliptic algorithm called ANALYN. The tangential contact, i.e. tangential stress distribution, stick-slip division and creep force calculation, is treated using an alternative to the FASTSIM algorithm that is based on a strip theory which extends the exact two-dimensional solution of rolling contact to three-dimensional contacts. The proposed contact model is compared to the Kik-Piotrowski model and evaluated using the CONTACT code in terms of contact patch and stress distribution as well as creep force curves. The results show that the proposed model can significantly improve the estimation of the contact solution both in terms of creep force estimation and contact details, such as stress distribution, needed for damage predictions.

  • 161. Six, K.
    et al.
    Mihalj, T.
    Trummer, G.
    Marte, C.
    Krishna, Visakh V
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Hossein Nia, Saeed
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Assessment of running gears regarding rolling contact fatigue of wheels and rails based on stochastic simulations2018Inngår i: Proceedings of the 11th International Conference on Contact Mechanics and Wear of Rail/wheel Systems, CM 2018, TU Delft , 2018, s. 878-885Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work a methodology is presented to assess running gears with respect to wheel and rail rolling contact fatigue (RCF). This assessment is based on wheel/rail contact data for different wheel profile wear states taken from a wheel profile prediction methodology. The approach allows e.g. The assessment of rail RCF in different curve radii in a cumulative way (sum of damage over lifetime of wheel profiles). Furthermore, RCF assessments can be done at different wear states of the wheel profiles to get insight how the contribution to wheel and rail RCF varies depending on the evolution of the wheel profiles. The presented methodology is exemplary applied to two bogie types, the UIC-Y25 standard bogie and the so called FR8RAIL bogie with a mechanical wheelset steering device. The presented methodology is a helpful tool e.g. To optimize vehicles already in an early stage of the development process. 

  • 162. Six, Klaus
    et al.
    Mihalj, Tomislav
    Trummer, Gerald
    Marte, Christof
    V Krishna, Visakh
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Hossein Nia, Saeed
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Assessment of running gear performance in relation to rolling contact fatigue of wheels and rails based on stochastic simulations2019Inngår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, s. 1-12, artikkel-id UNSP 0954409719879600Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, the authors present a methodology for assessing running gear with respect to rolling contact fatigue of wheels and rails. This assessment is based on the wheel/rail contact data of different wheel profile wear states obtained from a wheel profile prediction methodology. The approach allows a cumulative assessment of the rolling contact fatigue of rails in different curve radii (e.g. the sum of damage over the lifetime of wheel profiles). Furthermore, the assessment of the rolling contact fatigue can be undertaken at different wear states of the wheel profiles to provide an insight on how the rolling contact fatigue of wheels and rails varies depending on the evolution of wheel wear. The presented methodology is exemplarily applied to two bogie types, the UIC-Y25 standard bogie and the so-called FR8RAIL bogie with a mechanical wheelset steering device. The presented methodology has been shown to be a useful tool for the optimisation of vehicles already in an early stage of the vehicle development process.

  • 163.
    Sjöholm, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
     Benefits of regenerative braking and eco driving for high-speed trains:  Energy consumption and brake wear2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    on mechanical brakes. The electric regenerative brakes can thus be used as normal service brake with minimum time loss.The first part of the study aims at developing a method to calculate wear on train brake pads. This is done by using a reformulated version of Archard’s wear equation with a temperature dependent wear coefficient and a temperature model to predict the brake pad temperature during braking. The temperature model is calibrated using trustworthy data from a brake system supplier and full-scale test results.By performing simulations in the program STEC (Simulation of Train Energy Consumption), energy consumption for different cases of high-speed train operations is procured and significant data for the wear calculations are found. Simulations include both “normal driving techniques” and “eco driving”. The driving styles were decided through interviews with train drivers and experts on energy optimized driving systems.The simulations show that more powerful drive systems reduce both energy consumption and travel time by permitting higher acceleration and energy regeneration while braking. Calculations show that since the electric motors could carry out more of the braking the wear of the mechanical brakes becomes lower.Eco driving techniques can help to further reduce the energy consumption and mechanical brake wear. This driving style can require some time margins though, since it takes slightly longer time to drive when using coasting and avoiding speed peaks. However, if used properly this should not have to affect the actual travel time, partly because some time margins are always included in the timetable.Even if new, more powerful, trains would have the ability to reduce energy consumption and brake wear it is also necessary to have an appropriate slip control system for the electric brakes, making it possible to use them also under slippery conditions. In this context it is important that the adhesion utilization is modest, about 12 – 15 % for speeds up to 100 km/h and lower at higher speeds.

  • 164.
    Stensson Trigell, Annika
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Boij, Susann
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik.
    Efraimsson, Gunilla
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Aerodynamik.
    Jerrelind, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Numerisk akustik.
    ECO2 Vehicle Design: an initiative for a holistic perspective on future vehicle concepts2008Konferansepaper (Annet vitenskapelig)
  • 165.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Modellierung und Parameterstudien zum Fahrverhalten von Güterwagen mit UIC-Fahrwerken.1999Inngår i: ZEV+DET Glas.Annalen, Vol. 123, nr 6, s. 289-296Artikkel i tidsskrift (Fagfellevurdert)
  • 166.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    On freight vehicle dynamics and track interaction.1999Inngår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 213, nr 4Artikkel i tidsskrift (Fagfellevurdert)
  • 167.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Zum Einfluss der Strukturflexibilität des Untergestells auf das Laufverhalten von Güterwagen2003Inngår i: ZEV+DET. Glasers Annalen, nr June, s. 270-276Artikkel i tidsskrift (Fagfellevurdert)
  • 168.
    Stichel, Sebastian
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Casanueva, Carlos
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Hossein Nia, Saeed
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Wear and RCF prediction based on improved contact mechanics modelling2018Konferansepaper (Annet vitenskapelig)
  • 169.
    Stichel, Sebastian
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Jönsson, Per-Anders
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Is there a Future for Freight Wagon with Link Suspension?2009Inngår i: Proc. of the 9th International Heavy Haul Conference, IHHA´09, 2009Konferansepaper (Fagfellevurdert)
  • 170.
    Stichel, Sebastian
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Jönsson, Per-Anders
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg. TIKAB Strukturmekanik AB.
    Casanueva, Carlos
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Hossein Nia, Saeed
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Modeling and simulation of freight wagon with special attention to the prediction of track damage2014Inngår i: The international Journal of railway technology, ISSN 2049-5358, E-ISSN 2053-602X, Vol. 3, nr 1, s. 1-36Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper gives an overview of the state of the art of modelling and simulation of freight wagons. The main focus of the paper is to analyse the impact of freight wagons operation on track and wheel damage. Especially experiences of more than 15 years of modelling and simulation of a variety of freight wagons at KTH Royal Institute of Technology are summarized. Different models for the dry friction suspension elements are presented. The challenges of validation arising e.g. from the strong non-linearities and non-smoothness in vehicle models are discussed. Possibilities to use simulation results to predict wheel and track damage like wear, rolling contact fatigue and track settlement are introduced. It is concluded that it is possible to develop simulation models that give relevant results, even though it is more difficult than for passenger vehicles. The results, however, are very sensitive to small changes in the input parameters; therefore a sensitivity analysis regarding some key parameters should always be included in the validation phase of a model.

  • 171.
    Stichel, Sebastian
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Jönsson, Per-Anders
    Casanueva, Carlos
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Hossein Nia, Saeed
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Modelling and Simulation of Freight Wagon with Special attention to the Predication of Track Damage2014Inngår i: The international Journal of railway technology, ISSN 2049-5358, E-ISSN 2053-602XArtikkel i tidsskrift (Fagfellevurdert)
  • 172.
    Stichel, Sebastian
    et al.
    Bombardier Transportation, Västerås, Sweden .
    Persson, Rickard
    Bombardier Transportation, Västerås, Sweden .
    Himmelstein, Günther
    Andersson, Evert
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Orvnäs, Anneli
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Development of Next Generation High-Speed Trains for Scandinavia2009Inngår i: Proceedings of the 12th International Conference on Civil, Structural and Environmental Engineering Computing, 2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes the development of new running gear technology for future high-speed trains within the Swedish development programme Gröna Tåget (Green Train). Three different technologies are developed and tested: a passive radial self-steering "soft" bogie, an active lateral suspension including also a Hold-Off-Device function and a mechatronic bogie actively controlling the wheelset motions with actuators attached to the bogie frame. In contrast to other high-speed train developments, focus is here the challenge of balancing the contradictory demands of good running behaviour at high speeds on straight track on the one hand and good curving performance with low track and wheel damage and maintained good ride comfort on the other hand. Results are presented which confirm that all three technologies in almost all aspects meet the goals set up in the beginning of the project.

  • 173.
    Sánchez Arandojo, Adrián
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    On validation of a wheel-rail wear prediction code2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    During the past years, several tools have been developed to try predicting wheel and rail

    wear of railway vehicles in an e-cient way. In this MSc thesis a new wear prediction

    tool developed by I.Persson is studied and compared with another wear prediction tool,

    developed by T.Jendel, which has been already validated and is in use since several years

    ago. The advantages that the new model gives are simpler structure, the consideration of

    wear as a continuous variable and that all the code is integrated in the same software.

    The two models have the same methodology until the part of the wear calculations

    and the post-processing. Wheel-rail geometry functions and time domain simulations are

    performed with the software GENSYS.

    In the simulation model the track and the vehicle are dened as well as other important

    properties such as vehicle speed and coe-cient of friction. Three simple tracks are used:

    tangent track, R=500 m curve with a cant of ht=0.15 m on the outer rail and R=1000 m

    curve with a cant of ht=0.1 m on the outer rail. The model is assumed to be symmetric so

    just outer (first and fourth axle) and inner (second and third axles) wheels are considered.

    During the vehicle-track interaction, the normal and tangential problems are solved.

    The wheel-rail contact is modelled according to Hertz's theory and Kalker's simplied

    theory with the help of the algorithm FASTSIM. Then wear calculations are performed

    according to Archard's wear law. It is applied in dierent ways, obtaining wear depth

    directly in Jendel's and wear volume rate in Persson's model.

    Jendel's model is rstly analyzed. Its specifc methodology is briefly explained and

    modications are performed on the code to make it work as similar as possible to Persson's

    model. Also parameters regarding the distance in which wear calculations are taken, the

    discretization of the width of the wheel and the discretization of the contact patch are

    analyzed.

    The methodology of Persson's model is also studied, most of all the performance of the

    post-processing which is one of the keys to the code. The parameters analyzed in this code

    are the ones regarding a statistical analysis performed during the post-processing and the

    discretization of the contact patch.

    Finally the comparisons between the wear depth obtained for both models are carried

    out. The discrepancies between the models are explained with the parameters analyzed

    and the dynamic behaviour of both models. Also a theoretical case is used as reference for

    comparison.

  • 174.
    Thomas, Dirk
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    On Rail Vehicle Dynamics in Unsteady Crosswind Conditions: Studies Related to Modelling, Model Validation and Active Suspension2013Doktoravhandling, med artikler (Annet vitenskapelig)
    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.

  • 175.
    Thomas, Dirk
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Mats, Berg
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Persson, Rickard
    Bombardier Transportation.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Improving crosswind stability of fast rail vehicles using active secondary suspension2014Inngår i: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 52, nr 7, s. 909-921Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 176.
    Tyskeng, Sara
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Miljöstrategisk analys. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Boij, Susann
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Efraimsson, Gunilla
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Aeroakustik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Numerisk akustik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Ecological and economical Critera in Vehicle Design: Taking on the challenge2009Inngår i: Public Service Review: European Union, nr 19Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 177.
    Tyskeng, Sara
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Miljöstrategisk analys. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Jerrelind, Jenny
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Fordonsdynamik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Boij, Susann
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Efraimsson, Gunilla
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Aeroakustik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Berg, Mats
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Numerisk akustik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Centre for ECO2 Vehicle Design: vehicle design research for more environmentally friendly and economically competitive vehicles2008Inngår i: The Vehicle Component, SVENartikelArtikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 178.
    V Krishna, Visakh
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    The potential of Fluid Dynamic Absorbers for railway vehicle suspensions2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The main running objectives concerning the vertical dynamics of passenger rail vehicles are ride comfort and safety. The goal of this thesis is to employ the use of a Fluid Dynamic Absorber to minimize the vertical acceleration of the car body while minimizing the dy-namic force fluctuations in the wheel rail contact. The Fluid Dynamic Absorber is a device which employs a tube with a varying cross section containing oscillating fluid. The device is characterized by two effects: The inertia effect of the oscillating fluid in the varying cross section and the damping effect due to the pressure losses during the fluid flow. It is in-troduced as a potential damping device for automobiles and also for earthquake resistant buildings. The work encompasses the creation of a linearized approximation of the non-linear model for parameter selection. Then, a non-linear model is built with the help of the Modelica language for use in time simulation of quarter-car models in the Dymola interface. A generalized design methodology for the device is then developed with the help of design procedures used for common tuned mass dampers and liquid column dampers. Finally, the non-linear model built using the Dymola interface is also exported for use in the full-car model in Simpack using Functional Mock-up Interface. A reduction of about 4% to 5% in the magnitude of the root mean square of the carbody acceleration was observed while the wheel-rail dynamic forces remained the same. Further improvement possibilities and the parameters influencing the vertical dynamic behavior of the vehicle are discussed.

  • 179.
    V Krishna, Visakh
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Berg, Mats
    KTH, Tidigare Institutioner (före 2005), Farkost- och flygteknik. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Tidigare Institutioner (före 2005), Farkostteknik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Tidigare Institutioner (före 2005), Farkostteknik.
    Longitudinal Train Dynamics for Freight Wagons passing through an S-curve2017Inngår i: Proceedings of the First International Railway Symposium Aachen (IRSA) / [ed] Rik W. De Doncker, Nils Niessen, Christian Schindler, 2017, s. 193-203Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Efficient and safe operation of freight trains require assessment of its running behaviour. As the freight trains get longer the Longitudinal Train Dynamics (LTD) part becomes more pronounced on its running behaviour in particular when traditional pneumatic (P) braking is used. In this context, tight S-curves in switches form a critical infrastructure bottleneck in terms of running safety. Moreover, the train composition influences the longitudinal dynamics. This paper looks at the LTD involving an open wagon-train with multiple wagon types passing through an S-curve. For this purpose, 3D-simulations of push tests with some input from the UIC 530-2 norms are carried out in the Multi-Body Simulation (MBS) software GENSYS. Parameters such as the buffer-type, wagon positions and loading are also varied. Static Longitudinal Compressive Force (LCF) limits for different cases are presented and discussed.

  • 180.
    Vinberg, Erik Magni
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Energy use in the operational cycle of passenger rail vehicles2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master thesis investigates and analyzes the energy use for traction and auxiliary equipment in passenger rail vehicles. It covers both the train service with passengers and when the trains are going through other stages in the everyday operation. The operational cycle and associated operational situations are introduced as a way of describing the varying use of a train over time. The descriptions focus on the most common activities and situations, such as stabling and parking, regular cleaning, inspections and maintenance. Also how these situations affect energy use by their need for different auxiliary systems to be active.

    An energy model is developed based on the operational cycle as a primary input, together with relevant vehicle parameters and climate conditions. The latter proving to be a major influence on the energy used by the auxiliary equipment. The model is applied in two case studies, on SJ's X55 and Västtrafik's X61 trains. Both are modern electric multiple units equipped with energy meters. Model input is gathered from available technical documentation, previous studies and by measurements and parameter estimations. Operational cycle input is collected through different planning systems and rolling stock rosters. Climate input is finally compiled from open meteorological data banks.

    The results of the case studies show that the method and models are useful for studying the energy used by the trains in their operational cycles. With the possibility to distinguish the energy used by the auxiliary equipment, both during and outside the time the trains are in service with passengers. With this it's also possible to further investigate and study potential energy saving measures for the auxiliary equipment. Simulations of new ventilation control functions and improved use of existing operating modes on the trains show that considerable energy savings could be achieved with potentially very small investments or changes to the trains.

    The results generally show the importance of a continued investigation of the auxiliary equipment's energy use, as well as how the different operational situations other than the train service affect the total energy use.

  • 181.
    Vogel, Alexander
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Energy Usage of Personal Rapid Transit Systems: Simulation of the SkyCab Concept2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Den globala situationen för person- och godstransporter visar att energianvändningen inom transportsektorn stadigt ökar och prognoser tyder på att den kommer att fördubblas till 2050. Den största ökningen förväntas ske i Asien där, Kina kommer att stå för över 12 % av den globala energianvändningen år 2050. Inom EU, Europeiska Unionen, stod personbilarna 2012 för över 81 % av passagerartransporterna räknat i antal passagerarkilometrar. Nya energieffektiva och miljövänliga transportlösningar behöver utvecklas.

    En lösning med spårtaxi kombinerar fördelarna med konventionella vägtransportsystem (flexibilitet, tillgänglighet och attraktivitet) och spårtransportsystem (säkerhet, kapacitet och miljövänlighet). I detta examensarbete undersöks energianvändningen för spårtaxi. Detta sker i form av en fallstudie. Spårtaxi är en automatiserad transporttjänst för direktresor utan väntetider (likt taxiservice) i ett nätverk med banor som kompletterar masstransportsystem. Fokus i studien ligger på att utvärdera fordonens energianvändning i drift. Målet är att identifiera relevanta parametrar som avgör energianvändningen samt deras bidrag till denna. Frågan om effektiv energianvändning besvaras med hjälp av en simuleringsmodell. Denna baseras på konceptet SkyCab och en bedömning av fordonets parametrar. En beräkning är utförd som utgör en referens för att sedan jämföras med 16 variationer av nyckelparametrar. Relationen till växhusgaser undersöks och utsläppen beräknas för olika elektricitetsblandningar.

    Ett andragradspolynom är framtaget för att beskriva fordonets gångmotstånd som inkluderar uppskattningar av vagnens rullmotstånd för små, pneumatiska däck på en raksträcka samt i doserade kurvor. Hjälpkraftens energianvändning uppskattas säsom motsvarande en liten elektrisk bil och är starkt beroende av passagerarnas komfortbehov och yttre (väder)förhållanden.

    Ett resultat är att rullmotståndet står för cirka 44 % av energianvändningen och hjälpkraften för 33 %. Båda är potentiella mål för effektivitetsförbättringar. Ändringar av accelerationsnivåer har liten betydelse för energianvändningen då det är en mindre del av energin som regenereras. En ökning av topphastigheten är ett effektivt sätt att minska restiden med förhållanderis liten ökning av energianvändningen. Förslag lämnas i studien hur man kan minska energianvändningen genom att förbättra fordonets och banans nyckelegenskaper.

  • 182.
    Wennberg, David
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Light-weighting Methodology in Rail Vehicle Design through Introduction of Load Carrying Sandwich Panels2011Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Lightweight design in rail vehicles has been important for quite some time. Structures have been optimised to fulfill their purpose and cut unnecessary weight to reach allowable axle loads. Classically this is done by using steel, thin-walled structures, throughout the car body, or, alternatively, power-pressed aluminum profiles.

    The use of composites and sandwich structures has, however, been somewhat limited in the railway industry, especially when considering High-Speed trains. The anticipated weight savings, and reduced complexity of this type of structure are believed to have great potential in the future. This thesis covers the development of methods for structural stiffness design of lightweight, load carrying, sandwich panels for high-speed rail vehicles. Focusis on reducing the weight of the vehicles while simplifying the construction to reduce manufacturing costs and assembly times. Significant work is put into understanding the dynamic influence this type of structure has on the car body.

  • 183.
    Wennberg, David
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Multi-Functional Design of a Composite High-Speed Train Body Structure2014Inngår i: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 50, nr 3, s. 475-488Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A multi-level, multi-functional, optimisation methodology is suggested for the design of a composite high speed train car body. The structure consists of a layer of inner lining (glass fibre/vinyl ester), a layer of fibrous insulation, and a load carrying sandwich panel (carbon fibre/epoxy face sheets on a PMI core). Besides the most commonly used design constraints, such as mechanical strength, stiffness and geometry, also acoustic and thermal insulation as well as fire safety is included in the optimisation. The results suggest that well over 40 % mass reduction can be achieved with these types of structures.

  • 184.
    Wennberg, David
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Benefits of weight reduction in high speed train operations2013Inngår i: ZEV rail Glaser Annalen, ISSN 1618-8330, Vol. 137, nr 3, s. 77-87Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper highlights one of the main issues with light weight sandwich design in high-speed rail vehicles: The benefit of light weighting is said to be marginal when considering high-speed trains. A run cycle based analysis method is used to evaluate energy savings, wear reduction, downsizing possibilities and reduced travel time as function of reduced weight. Depending on operating conditions, the relation between weight reduction and energy consumption for high-speed trains is shown to be equivalent of that for both automobiles and aircrafts.

  • 185.
    Wennberg, David
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Cutting the Weight of High-Speed Trains2011Inngår i: Railway Gazette International, ISSN 0373-5346, Vol. 167, nr 1, s. 30-32Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 186.
    Wennberg, David
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Finite difference adaptation of the decomposition of layered composite structures on irregular grid2014Inngår i: Journal of composite materials, ISSN 0021-9983, E-ISSN 1530-793X, Vol. 48, nr 20, s. 2427-2439Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The finite difference method is used to solve the time-dependent thermo mechanical response of a layered composite structure subjected to fire. State variables of the composite are chosen whereby the external and internal boundary conditions are derived for an irregular grid through the thickness of the structure. The homogenised mass flux and specific heat capacity of pyrolysis gases over a layered composite is also defined. The formulations are tested against documented results found in the literature.

  • 187.
    Wennberg, David
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Optimisation of sandwich panels for the load carrying structure of high-speed rail vehicles2012Inngår i: International Journal of Aerospace and Lightweight Structures, ISSN 2010-4286, Vol. 2, nr 1, s. 19-40Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper investigates how various requirements, such as stiffness, strength, buckling, thickness and area density, influence the choice of load carrying sandwich panels for highspeed rail vehicles. Requirements on the load carrying structure are defined where after various sandwich alternatives are chosen to match these requirements. The initial panels are optimised with the software package HyperWorks. Refined optimisation results are then studied by Finite Element Analysis. A total weight reduction of over 30% of the load carrying structure is achieved.

  • 188.
    Wennberg, David
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Substitution of corrugated sheets in a railway vehicle's body structure by a multiple-requirement based selection process2014Inngår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 228, nr 2, s. 143-157Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To simplify construction, reduce weight and improve mechanical properties, a sandwich panel substitution process is performed on corrugated sheets in the floor and roof of a rail vehicle car body. A requirement based selection is used to design the sandwich panels with the corrugated sheet mechanical characteristics as boundaries. Car body stiffness is evaluated by modal analysis. The derived panels reduce the mass of the car body by 600-700kg. Results show the varying importance of the longitudinal, transverse and shear properties of the floor and roof panels, as well as how efficient the corrugated sheets actually are.

  • 189.
    Wennberg, David
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Orthotropic models of corrugated sheets in finite element analysis2011Inngår i: Mechanical engineering (New York, N.Y. 1919), ISSN 0025-6501, E-ISSN 1943-5649Artikkel i tidsskrift (Fagfellevurdert)
  • 190.
    Wennberg, David
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Centra, Järnvägsgruppen, JVG.
    Selection of sandwich panels for the load carrying structure of high-speed rail vehicles2011Konferansepaper (Annet vitenskapelig)
  • 191.
    Zhang, Jingwen
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Influence of suspension modellingon predicted ride comforton passenger rail vehicles2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of this this report was to find the sources that led to the deviation between the simulation and measurement on the ride comfort evaluation of a high-speed train. This report consists of a literature study, introduction of the train where the measurement was taken on, result analysis and sensitivity test of the secondary suspension. The literature study focused on the modelling of secondary suspensions and the simulation of rail vehicles. The predicted results were compared with the measured results. Furthermore, comparison was carried out among three different secondary suspension concepts. The secondary suspensions went through a sensitivity test to see how the parameters influence the ride comfort evaluation of the rail vehicle.It was figured out that the main deviation between the simulation and the measurement was focused on a carbody where a hydraulic damper was introduced. The difference was mainly at 1.3Hz and between 7.5Hz and 9Hz.With the main deviations figured out, the sources that might influence the ride comfort evaluation was tested. It showed that the detail of track measurement had influence on the ride comfort evaluation. More detailed measurement should be carried out if higher agreement is wanted. The secondary suspensions went through a sensitivity test. The key parameters and their influence on ride comfort evaluation was pointed out. This report can be a guidance if further tuning on the parameters of the secondary suspensions are needed.

  • 192.
    Zhendong, Liu
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Stichel, Sebastian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Anders, Rønnquist
    NTNU Norwegian University of Science and Technology.
    Numerical Study on the Dynamic Behaviour of Railway Catenary Overlap Section for Higher Speed2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The dynamic behaviour in the contact between pantograph and catenary decides the quality of power transmission, the component service life and the maximum operational speed. The catenary system is desired to be built smooth and uniform in geometry and elasticity along the train-running direction, but due to electric concerns and tensile force retention, the entire catenary is made up by many tensioning sections. To make a pantograph smoothly shift between the neighbouring sections, an overlap of several spans is introduced to work as a transition zone. However, when the pantograph is passing through the overlap section, its dynamic behaviour can be heavily changed and cannot sustain as good contact as in the middle spans of each tensioning section. To clarify the dynamic behaviour in this special section and to ensure a stable contact between pantograph and catenary, a numerical study on catenary section overlap is performed based on a 3D pantograph-catenary finite element (FE) model. The following issues are discussed in this paper: operational speed, wire gradient, damping ratio, and spacing distance in multi-pantograph operation. The results show that the gradient of wires in overlap sections and the damping ratio have great influence on the dynamic performance, especially at high speed and in multi-pantograph operation. In practice, in the overlap section the gradient should be properly designed and some additional damping is beneficial to ensure good dynamic performance for higher speed.  

  • 193.
    Zhu, Anlin
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    Railway Infrastructure Management - System Engineering and Requirement Management2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Rail Control Solutions (RCS) is one division of Bombardier Transportation, aimed at optimising flow of trains. OPTIFLO is a new solution package within RCS, providing services and solutions to address challenges in modern railway infrastructures worldwide. Infrastructure Management (IM) Service is a significant sub-module under OPTIFLO, performing monitoring and diagnostic functionalities for each impacted system or component in railway signalling systems to continuously improve safety, reliability and availability.

    Requirement management is a significant stage while dealing with engineering problems. In this master thesis project, three modules in railway signalling scope are focused, including system level Infrastructure Management, sub-system level Maintenance and Diagnostic Centre (MDC) and sub-system level Remote Sensor Unit (RSU). For each part, requirement managements have been implemented, referring to CENELEC standards where necessary. The work starts with the draft Requirement Specification for IM and then identify the requirements related to diagnostics and performance in each sub-system. Both links between the requirements in different modules and links between the requirements and their test cases are built from the requirement management tool DOORS to realize verification and validation following the system engineering process. Finally, the standard documentations "System Requirement Specification" for each impacted module that are mostly concerned in the thesis have been released.

  • 194.
    Öhnander, Fred
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Spårfordon.
    An Attempt Towards FE-Modelling of Fracture Propagation in Railway Wheels2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The demand for higher velocities and heavier axle loads for freight trains leads to higher forces on the railway wheels which in turn lead to an increase in stresses on and below the surface of the wheel-rail contact. By time, this induces wear on the wheels which consequently lead to higher maintenance costs and in some cases accidents. The ability to predict the evolution of wheel profiles due to uniform wear has been demonstrated with a rather accurate precision in most operational conditions. These wear models are based on wear coefficients and since they are not usually valid for real operational conditions, the models are generally calibrated against real-life scenarios in order to adjust the coefficients from test conditions to real-life lubrication conditions. This engineering approach can be useful in prediction of wear in systems where the materials and contact conditions do not vary. However, when addressing material development focused on reducing specific damage modes, the approach is of limited use because the obtained wear coefficients are not directly related to material properties. Therefore, attempts towards developing physical fracture propagation models that relates to the contact conditions and material properties have been made. The purpose has been to retrieve vital information about where a fracture initiates and how it propagates. In the long run, it is of great interest to be able to attain information about how a material particle is removed from the contact surface. Studies for this type of model was done in the 70’s and 80’s mainly with pin-disk experiments but has not been utilized in the specific field of wheel-rail contact. The thesis is part of the FR8RAIL project arranged by the European rail initiative Shift2Rail. Literature studies have been the basis for the thesis in order to gain vital insights into fracture mechanics and other related fields. The physical fracture propagation models have been constructed in the FE software Abaqus with the implementation of the XFEM. For the 2D model, the fracture initiates at the top of the implanted inclusion when the friction coefficient is  and propagates upwards a few elements. For , the fracture initiates at the right surface boundary where the pressure distribution and traction is applied. The fracture propagation angle increases relative to the surface as the friction coefficient value is increased. The fracture for the 3D model extends broader compared to the 2D model at the top of the inclusion in the case of . The fracture initiates at the same surface location as for the 2D model for . The fracture propagation is however non-existent due to convergence problems. The FE-models constructed are initial steps towards analysing the fracture propagation and closely related phenomena for a railway freight wheel in detail. At the end of the thesis, the simplified models give mainly information about the fracture initiation, propagation and its patterns. From this first phase, further adjustments and improvements can take place in order to eliminate the margins of error. In the long run, fully integrated models with further implementations such as detailed microstructure for the contact conditions, plastic behaviour for the material, and complete three-dimensional models can finally be employed.

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