| 1. |
- Alonso, Asier, et al.
(författare)
-
Modelling of rough wheel-rail contact for physical damage calculations
- 2019
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 436
-
Tidskriftsartikel (refereegranskat)abstract
- This work presents the initial steps given in order to obtain a comprehensive physical damage model for the specific case of wheel rail contact wear, which would be able to relate contact conditions, material properties and wear rates. The main advantage of a physical damage wear model is that wheelset and rail manufacturers can perform simulations in order to improve and optimise material properties for different operational cases. The work in this paper focuses on delaminative wear, starting with the importance and modelling of rough contact, and a comparison against classic smooth contact models.
|
|
| 2. |
- Alonso, Asier, et al.
(författare)
-
Physical damage mechanisms for uniform wear calculation
- 2018
-
Ingår i: Proceedings of the 11th International Conference on Contact Mechanics and Wear of Rail/wheel Systems, CM 2018. - Delft, The Netherlands.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This work presents the initial steps given in order to obtain a comprehensive physical model for the specific case of wheel rail contact, which would be able to relate contact conditions, material properties and wear rates. The main advantage of a physical damage wear model is that wheelset an rail manufacturers can perform simulations in order to improve and optimize material properties for different operational cases. The initial work has focused on delaminative wear, starting with the importance and modelling of rough contact, and a comparison against classic smooth contact models.
|
|
| 3. |
- Andersson, Evert, et al.
(författare)
-
Assessment of train-overturning risk due to strong cross-winds
- 2004
-
Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 218:3, s. 213-223
-
Tidskriftsartikel (refereegranskat)abstract
- This paper describes the methodology for safety assessment related to the risk of a train overturning in strong cross-winds. As an example, this methodology is applied on the high-speed line Botniabanan being built for a maximum speed of 250 km/h in the northeast coastal region of Sweden. The process starts with a systematic identification of locations along the line having a potential high risk of overturning due to cross-winds. This is followed by a cross-disciplinary study. The first step is to estimate the probabilities of wind velocity and wind directions. The next step is aerodynamic computation of overturning forces and moments acting on relevant types of train. Further, the critical overturning wind velocity is determined by a multi-body simulation technique. Finally, the overturning accident frequency is calculated. The calculated risk is compared with generally accepted risk levels in modern train operation.
|
|
| 4. |
- Andersson, Evert, et al.
(författare)
-
Green Train: concept and technology overview
- 2014
-
Ingår i: International Journal of Rail Transportation. - : Taylor & Francis Group. - 2324-8386 .- 2324-8378. ; 2:1, s. 2-16
-
Tidskriftsartikel (refereegranskat)abstract
- Green Train (in Swedish, Gröna Tåget) is a research, development and demonstrationprogramme with the overall objective to define an economical, flexible and environmentallyfriendly train concept. The objective is also to develop technology for futurehigh-speed trains for the northern European market, particularly for Scandinavia. Mostof the technology developed is also applicable to other world markets, as well as toslower trains. The programme has covered many important areas, including economy,capacity and market aspects, conceptual design, traveller attractiveness and interiors,travel time, energy efficiency and noise, winter performance, track friendliness and carbody tilt, aerodynamics, electric propulsion and current collection. The programme hasconducted fundamental analysis and research on the different issues as well as designand testing of new technologies. A number of crucial technologies have undergoneperformance and type testing both in lab and on a test train. Experience feedback wasachieved in commercial train service during the period 2006−2013 including harshwinters. This paper summarises a great deal of research and development that has beenperformed in the Green Train programme.
|
|
| 5. |
- Andersson, Evert, et al.
(författare)
-
Gröna Tåget - Green Train - Train for tomorrow's travellers
- 2011
-
Ingår i: ZEVrail. - Berlin : Georg Siemens Verlag. - 1618-8330. ; 135, s. 140-153
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Gröna Tåget (Green Train) is a Swedish research and development programme aiming at defining a concept and developing technology for the next generation high-speed trains, suitable for the Northern European countries. The programme involves almost all major stakeholders in the railway business in Sweden. Main sponsors are Trafikverket (former Banverket) as well as the railway industry and operators (Bombardier, SJ and others). The total budget is around 15 million EUR. The technical coordination is with the Royal Institute of Technology (KTH) in Stockholm. The program started in 2005 and will continue until the end of 2011.Gröna Tåget is intended to be a fast, track-friendly, electric tilting train that can not only maintain higher speeds than conventional trains on sections with curves, but special versions could allow 300 km/h or more on future dedicated high-speed lines. Gröna Tåget shall be more attractive and more cost effective both to travellers and to operators than today’s trains. Environmental performance (energy use per passenger, noise) is expected to be still better than existing trains at lower speed.
|
|
| 6. |
- Andersson, Evert, et al.
(författare)
-
How to find a compromise between track friendliness and the ability to run at high speed
- 2012
-
Ingår i: Civil-Comp Proceedings. - Stirlingshire, UK : Civil-Comp Press. - 1759-3433. ; 98
-
Tidskriftsartikel (refereegranskat)abstract
- When designing and optimizing a rail vehicle there is a contradiction between, on the one hand, stability on straight track at high speed and, on the other hand, reasonable wheel and rail wear in small- and medium-radius curves. This paper describes the process of developing and optimizing a track-friendly bogie. A simulation model has been used to investigate dynamic stability on straight track at high speeds along with the wheel and rail wear in sharper curves. The result is a bogie with relatively soft wheelset guidance allowing passive radial self-steering, which in combination with appropriate yaw damping ensures stability on straight track at higher speeds. This bogie has been tested according to EN 14363 at speeds up to about 300 km/h and in curves with radii ranging from 250 m and up.
|
|
| 7. |
- Andersson, Evert, et al.
(författare)
-
Rail Systems and Rail Vehicles : Part 2: Rail Vehicles
- 2016. - 1
-
Bok (populärvet., debatt m.m.)abstract
- This compendium is mainly intended for MSc education in rail vehicle engineering at KTH Royal Institute of Technology, Stockholm, Sweden. The objective is to give an overview and fundamental knowledge of different rail systems, followed by a more thorough introduction to rail vehicles. In this way most rail aspects are covered. The compendium consists of 20 chapters.
|
|
| 8. |
- Andersson, Evert, et al.
(författare)
-
Varför behövs Nya Stambanor i Sverige?
- 2020
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Stora investeringar och omdaningar planeras i vårt transportsystem. Transporterna väntas öka starkt i framtiden och mera kapacitet måste skapas på ett hållbart sätt. Diskussionerna om vilka transportmedel som ska prioriteras, såväl som vilka objekt som vi ska satsa på, är livliga.En viktig fråga är satsningen på Nya Stambanor avsedda för snabba persontransporter i de redan idag hårt belastade stråken Stockholm‒Göteborg och Stockholm‒Malmö, med ett stort antal mellanliggande orter. Denna typ av järnvägar finns redan eller planeras i de flesta av världens ledande ekonomier. Syftet med att bygga nya stambanor är att öka den totala kapaciteten för person- och godstrafik på järnväg, öka punktligheten och öka tillgängligheten genom korta restider. Det ger också förutsättningar för större regionala arbetsmarknader och ökat bostadsbyggande utanför storstäderna samt en bättre miljö. Nuvarande stambanor avlastas och lämnar plats för bl a effektivare godstransporter.Denna rapport behandlar först järnvägens egenskaper. Järnvägen är det energieffektivaste transportmedel vi känner till, den tar liten plats och är mycket trafiksäker. Moderna tåg på modern bana är vårt snabbaste transportmedel till lands. Tåg kan bereda plats och komfort för arbete och avkoppling under resan. Enligt författarnas uppfattning bör dessa egenskaper göra järnvägen till ett förstahandsalternativ för effektiva och hållbara transporter i de segment där järnvägen är eller kan bli konkurrenskraftig.Prognoser och analys, samt erfarenheter från utlandet, visar att trafikunderlaget i Sverige är tillräckligt för nya stambanor. Med de förslagna banorna väntas järnvägens totala kapacitet öka till mer än det dubbla i de mest belastade stråken. En viktig faktor är att den snabba och långsamma tågtrafiken separeras. Denna åtgärd ger ökad kapacitet, utöver vad de dubblerade spåren ger, eftersom tågen kan köra tätare efter varandra och störningarna i tågtrafiken minskar.Restiderna för orterna längs de nya stambanorna minskar kraftigt, i regel mellan 30 och 65%. Tillsammans med ökad turtäthet och minskade störningar ger det stora ökningar av tågtrafiken. De officiella prognoserna lider dock av ett antal allvarliga brister, varför både trafikökningen och den samhällsekonomiska lönsamheten beräkningsmässigt framstår som mindre än vad den enligt KTH:s prognoser och internationell erfarenhet borde vara.Författarna anser att anläggningskostnaderna är rimliga i relation till nyttorna och jämfört med vad andra omställningar i samhällets transportsystem kostar. Detsamma gäller den engångs ”klimatskuld” som uppkommer vid de flesta satsningar för framtiden inom alla trafikslag. Nya transportslag i ett tidigt utvecklingsskede (elflyg, magnettåg, Hyperloop etc) är mycket osäkra beträffande när eller om de överhuvudtaget kommer att bli tillgängliga för användning i stor skala. I flera fall skulle krävas stora tekniska genombrott som vi idag inte känner till. Vi anser att man rimligen inte idag kan besluta att satsa på helt nya tekniska system för vilka framtiden är mycket osäker. Vi kan inte heller ”vänta och se”, eftersom ytterligare kapacitet behövs redan idag och ledtiderna är långa.Sammanfattningsvis är de nya stambanorna ett samhällsbyggnadsprojekt och en del i transportsektorns nödvändiga omställning. De ger korta restider och effektiva transporter mellan våra största städer, liksom till och från ett stort antal mellanliggande orter, med omnejd. Godstransporterna kan också få plats på spåren och de kan utvecklas och effektiviseras. Det handlar om hållbar mobilitet för människor och gods i framtiden.
|
|
| 9. |
- Bernal, Esteban, et al.
(författare)
-
Friction-Slip Curves - The Pathway From Twin-Disc Tribo Measurements To Full-Scale Locomotive Multibody Simulations
- 2022
-
Ingår i: PROCEEDINGS OF 2022 JOINT RAIL CONFERENCE (JRC2022). - : AMER SOC MECHANICAL ENGINEERS.
-
Konferensbidrag (refereegranskat)abstract
- Locomotive multibody simulations are commonly used as a cost-effective tool to study, energy efficiency, wheel-rail wear, rolling contact fatigue, etc. The accuracy of the wheel-rail contact forces from multibody simulations depends on the correct modelling of the friction conditions. The friction coefficient is a function of the slip velocity, and it is influenced by several tribological parameters including, for example, material mechanical properties, environmental conditions and the presence of third body layers that vary spatially and temporally along the track. In most cases, generic friction-slip curves obtained from publications and public reports are used as inputs to the wheel-rail contact model in the locomotive simulations, as direct friction measurements using full-scale experimental set-ups are generally cost-prohibitive. A pathway to produce friction-slip curves from tribo-machine friction measurements is proposed in this paper. The pathway involves manufacturing discs from actual wheel and rail material samples to measure the traction coefficient at a spectrum of slip set points using a twin-disc tribo-machine. The tribo-machine results are scaled to be used in a locomotive multibody model that uses the modified Fastsim and a traction system co-simulation approach. Two friction curves for wet and dry conditions are processed and exemplified in a dynamic model.
|
|
| 10. |
- Bernal, Esteban, et al.
(författare)
-
Prediction of rail surface damage in locomotive traction operations using laboratory-field measured and calibrated data
- 2022
-
Ingår i: Engineering Failure Analysis. - : Elsevier BV. - 1350-6307 .- 1873-1961. ; 135
-
Tidskriftsartikel (refereegranskat)abstract
- Rail damage prediction is a complex task because it depends on numerous tribological parameters and the dynamic conditions produced by the vehicles operating at different speeds and configurations. Shakedown maps and Whole-Life-Rail-Model/T-Gamma have been used to predict rail damage, but they involve assumptions that may reduce their accuracy. This paper proposes a simulation modelling method to predict rail surface damage based on a locomotive digital twin, calibrated shakedown maps and friction measurements. The method improves the accuracy of rail damage predictions by including slip-dependent friction characteristics, co-simulation of locomotive traction mechatronic system and the mechanical properties of the wheel and rail materials measured through tensile tests. A set of operating conditions are simulated on a high-performance computing cluster, with stress results being post processed into calibrated shakedown heatmaps. The method clearly indicated the influences of the different operating conditions on rail damage for specific combinations of wheel-rail materials and vehicle-track configurations.
|
|
| 11. |
- Bruni, Stefano, et al.
(författare)
-
Modelling of suspension components in a rail vehicle dynamics context
- 2011
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 49:7, s. 1021-1072
-
Tidskriftsartikel (refereegranskat)abstract
- Suspension components play key roles in the running behaviour of rail vehicles, and therefore, mathematical models of suspension components are essential ingredients of railway vehicle multi-body models. The aims of this paper are to review existing models for railway vehicle suspension components and their use for railway vehicle dynamics multi-body simulations, to describe how model parameters can be defined and to discuss the required level of detail of component models in view of the accuracy expected from the overall simulation model. This paper also addresses track models in use for railway vehicle dynamics simulations, recognising their relevance as an indispensable component of the system simulation model. Finally, this paper reviews methods presently in use for the checking and validation of the simulation model.
|
|
| 12. |
|
|
| 13. |
- Bruni, Stefano, et al.
(författare)
-
The results of the pantograph-catenary interaction benchmark
- 2015
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 53:3, s. 412-435
-
Tidskriftsartikel (refereegranskat)abstract
- This paper describes the results of a voluntary benchmark initiative concerning the simulation of pantograph-catenary interaction, which was proposed and coordinated by Politecnico di Milano and participated by 10 research institutions established in 9 different countries across Europe and Asia. The aims of the benchmark are to assess the dispersion of results on the same simulation study cases, to demonstrate the accuracy of numerical methodologies and simulation models and to identify the best suited modelling approaches to study pantograph-catenary interaction. One static and three dynamic simulation cases were defined for a non-existing but realistic high-speed pantograph-catenary couple. These cases were run using 10 of the major simulation codes presently in use for the study of pantograph-catenary interaction, and the results are presented and critically discussed here. All input data required to run the study cases are also provided, allowing the use of this benchmark as a term of comparison for other simulation codes.
|
|
| 14. |
- Bucca, Giuseppe, et al.
(författare)
-
Adoption of different pantographs' preloads to improve multiple collection and speed up existing lines
- 2012
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 50:SUPPL. 1, s. 403-418
-
Tidskriftsartikel (refereegranskat)abstract
- The current collection using more than one pantograph is needed in railway operation to provide power to non-electrically connected traction units and, in some cases, to reduce current density on the collector strips that heavily influences the wear on the contacting bodies. The multiple current collection may become a critical condition due to the mechanical disturbances produced on the trailing pantographs by the interaction between the first pantograph and the catenary. The present-day evolution of pantograph preload regulating systems, exploiting pressure-controlled servo-valves driven by electronic units, allows a diversification of the preloads of front and rear pantographs. In this work, a suitable solution to improve multiple pantograph collection quality is analysed by the use of a lower mean force on the leading pantograph aimed at reducing the oscillations of contact wire the trailing pantograph is subjected to. This would improve the current collection quality of the trailing pantograph, and could be pursued even admitting a slight worsening of front pantograph's performances.
|
|
| 15. |
|
|
| 16. |
- Casanueva, Carlos, 1981-, et al.
(författare)
-
Influence of switches and crossings on wheel profile evolution in freight vehicles
- 2014
-
Ingår i: Vehicle System Dynamics. - : Taylor & Francis. - 0042-3114 .- 1744-5159. ; 52:SI, s. 317-337
-
Tidskriftsartikel (refereegranskat)abstract
- Wheel reprofiling costs for freight vehicles are a major issue in Sweden, reducing the profitability of freight traffic operations and therefore hindering the modal shift needed for achieving reduced emissions. In order to understand the damage modes in freight vehicles, uniform wear prediction with Archard's wear law has been studied in a two-axle timber transport wagon, and simulation results have been compared to measurements. Challenges of wheel wear prediction in freight wagons are discussed, including the influence of block brakes and switches and crossings. The latter have a major influence on the profile evolution of this case study, so specific simulations are performed and a thorough discussion is carried out.
|
|
| 17. |
|
|
| 18. |
- Casanueva, Carlos, 1981-, et al.
(författare)
-
On integrated wheel and track damage prediction using vehicle-track dynamic simulations
- 2017
-
Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : Sage Publications. - 0954-4097 .- 2041-3017. ; 231:7, s. 775-785
-
Tidskriftsartikel (refereegranskat)abstract
- The renewal costs for wheels and rails are a substantial part of the costs for rolling stock operators and infrastructure managers all over the world. The causes for reprofiling or grinding are, in most cases, related to the following: (1) wheel or rail profiles with unacceptable wear, (2) appearance of rolling contact fatigue cracks in the surface, and (3) wheel flats caused by locking wheels during braking. The first two causes are related to the dynamic behavior of the vehicle-track system, and can be predicted using multibody simulations. However, there are several limitations that restrain the usefulness of these prediction techniques, such as simulation time constraints, necessary simplifications, and lack of experimental data that lead to educated assumptions. In this paper, we take the end-user perspective in order to show whether the latest developments in wheel-rail damage prediction can be integrated in a simplified framework, and subsequently used by the different stakeholders for an improved management of the different assets involved in the operation of rail vehicles.
|
|
| 19. |
- Casanueva, Carlos, 1981-, et al.
(författare)
-
System-wide impact of vehicle innovations : Evaluating track-friendliness during vehicle design
- 2021
-
Ingår i: Proceedings of the Resource Efficient Vehicles Conference - 2021 (rev2021)<em></em>.
-
Konferensbidrag (refereegranskat)abstract
- The cost of maintenance of railway tracks due to vehicle passage is a major limiting factor to the competitiveness of railway sector in EU. For instance, in Sweden in 2017only, 2800million SEK was spent on track maintenance and reinvestment due to wear and tear caused by traffic. Considering this, there is a major incentive to operate track-friendly vehicles that also facilitate economically feasible maintenance strategies. In this context, the NEXTGEAR project aims to incorporate a track-friendliness module in the ‘Universal Cost Model 2.0’ that can estimate operating costs for a given set of operational parameters such as vehicle suspension design, energy usage, track geometry, etc. Such a tool could be useful in estimating the costs for a train operator for a given route and application. However, estimation of costs due to track damage is a complex cross-disciplinary task encompassing varying domains such as vehicle dynamics, tribology, economics, maintenance policy etc so that actual damage in the infrastructure can be linked to maintenance actions and thus costs. Currently there are two major diametrical approaches such as the ‘Bottom-up’ Engineering approach that seeks to create accurate engineeringmodels of vehicle, track, etc. Then there is the ‘Top-down’ Econometric approach that seeks to create statistical models linking the operating variables with historically recorded cost data. Also, track damage itself manifests in various forms such as wear RCF and settlement and it is extremely useful to understand the distribution of costs amongst them. Nowadays a Hybrid approach isbeingdeveloped that can bridge the limitations of the other two methods. Eventually all these models seek to calculate differential operating costs due to the introduction of vehicle innovations during the design stage, hence contributing to the overall economic feasibility of the railway system
|
|
| 20. |
- Casanueva, Carlos, 1981-, et al.
(författare)
-
Uniform Wheel Wear of a Two Axle Freight Vehicle with Friction Dampers
- 2012
-
Ingår i: Proceedings of the First International Conference on Railway Technology. - Stirlingshire, UK : Civil-Comp Press. ; , s. Paper 93-
-
Konferensbidrag (refereegranskat)abstract
- Wheel reprofiling accounts for a considerable amount of the maintenance costs forfreight wagons in Sweden, and the causes can be divided mainly in three groups:wheel flats, shelling and uniform wear. In this paper the development of uniformwheel wear in a two-axle freight vehicle is studied. This wagon with Unitruckrunning gear had a major modification in the suspension elements in 2005 whichhighly reduced flange wear. The method developed at KTH for uniform wearcalculation is applied on both old and new simulation models. The influence offreight wagon specific characteristics on the wear development is also analysed, i.e.high axle load and friction damping elements.
|
|
| 21. |
- Casanueva, Carlos, 1981-, et al.
(författare)
-
Use of Archard's wear law for the calculation of uniform wheel wear of high tonnage freight vehicles
- 2013
-
Ingår i: Proceedings of the 1st Joint Rail Conference. - : ASME Press. - 9780791855300 ; , s. JRC2013-2545-
-
Konferensbidrag (refereegranskat)abstract
- Wheel profile evolution has a large influence on track and wheelset related maintenance costs. It influences important parameters such as equivalent conicity or contact point positioning, which will affect the dynamic behavior of the vehicle, in both tangent track and curve negotiation. High axle loads in freight wagons may increase both the wheel wear and the damage caused by vehicles with both new and already worn profiles. A common profile in Europe is the S1002 profile, developed for rail inclination 1/40. In Sweden rail inclination is 1/30, so contact conditions might not be optimal. The presented work uses Archard’s wear law to analyze the profile wear evolution in a two axle freight vehicle with Unitruck running gear on the Swedish network. This wear calculation methodology has been successfully used to predict uniform wear in passenger vehicles. First, the vehicle model has been optimized in order to improve the speed of the wear simulations. Experimental measurements of wheel profiles have been performed in order to validate the simulations. The conclusion is that the wear methodology successfully used to predict uniform wheel wear in passenger vehicles cannot be directly applied for the calculation of wheel profile evolution in high tonnage freight vehicles. The influence of block brakes or switches and crossings cannot be dismissed when calculating uniform wheel wear in these cases.
|
|
| 22. |
- Chen, Shaoyao, et al.
(författare)
-
Modified Wear Modelling for Fast Wear Calculation
- 2022
-
Ingår i: IAVSD 2021: Advances in Dynamics of Vehicles on Roads and Tracks II. - Cham : Springer Nature. ; , s. 561-571
-
Konferensbidrag (refereegranskat)abstract
- In this paper, a modified wear calculation method is developed, which can give less precise but faster results compared to the classic wear calculation method. Besides, a precise contact point detection program is developed to cooperate with this modified method.
|
|
| 23. |
- Diedrichs, Ben, et al.
(författare)
-
Quasistatic modelling of wheel-rail reaction due to crosswind effects for various types of high-speed rolling stock
- 2004
-
Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 218:2, s. 133-148
-
Tidskriftsartikel (refereegranskat)abstract
- This work describes a quasi-static tool developed to assess the performance swiftly of crosswind stability for three types of rolling stock with conventional, semi-trailer and Jacobs bogie running gear configurations. The prediction accuracy of the results returned by the tool for the quasistatic assumption is fair in comparison with results of more advanced multibody simulation software that is commercially available. The codes, which are based on steady equilibrium equations for the wheels and axles, bogie frames and vehicle body/bodies, handle arbitrarily canted embankments and circular curves. To a large extent the accuracy hinges on the bodies' lateral displacements relative to the contact points between the wheels and rails; therefore proper modelling of the suspension systems and bump stops are found to be important. Examples are given of the limitations associated with the quasi-static approach, studying the following: (a) the combined wind and track scenario in Deutsche Bahn AG's guideline, (b) the effects of typical track irregularities for high-speed transportation as a function of train speed and (c) the effects of oscillating crosswind. It has also been found relevant to demonstrate some of the large differences regarding provisions regulating crosswind safety. To this extent the present results are compared with those derived with the British Group Standard and also with results presented in the guideline of Deutsche Balm AG. In addition, examples are given of the differences found of the permissible crosswind speed using calculated (with CFD-RANS) and experimentally obtained aerodynamic loads.
|
|
| 24. |
- Diedrichs, Ben, et al.
(författare)
-
Vehicle dynamics of a high-speed passenger car due to aerodynamics inside tunnels
- 2007
-
Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - 0954-4097 .- 2041-3017. ; 221:4, s. 527-545
-
Tidskriftsartikel (refereegranskat)abstract
- High train speeds inside narrow double-track tunnels using light car bodies can reduce the ride comfort of trains as a consequence of the unsteadiness of the aerodynamics. This fact was substantiated in Japan with the introduction of the series 300 Shinkansen trains more than a decade ago, where the train speed is very high also in relatively narrow tunnels on the Sanyo line.The current work considers the resulting effects of vehicle dynamics and ride comfort with multi-body dynamics using a model of the end car of the German high-speed train ICE 2. The present efforts are different from traditional vehicle dynamic studies, where disturbances are introduced through the track only. Here disturbances are also applied to the car body, which conventional suspension systems are not designed to cope with.Vehicle dynamic implications of unsteady aerodynamic loads from a previous study are examined. These loads were obtained with large eddy simulations based on the geometry of the ICE 2 and Shinkansen 300 trains.A sensitivity study of some relevant vehicle parameters is carried out with frequency response analysis (FRA) and time domain simulations. A comparison of these two approaches shows that results which are obtained with the much swifter FRA technique are accurate also for sizable unsteady aerodynamic loads. FRA is, therefore, shown to be a useful tool to predict ride comfort in the current context.The car body mass is found to be a key parameter for car body vibrations, where loads are applied directly to the car body. For the current vehicle model, a mass reduction of the car body is predicted to be most momentous in the vicinity of 2 Hz.
|
|
| 25. |
- Dou, W., et al.
(författare)
-
A boundary-condition-transfer method for shell-to-solid submodeling and its application in high-speed trains
- 2020
-
Ingår i: International Journal of Mechanical Sciences. - : Elsevier. - 0020-7403 .- 1879-2162. ; 177
-
Tidskriftsartikel (refereegranskat)abstract
- The boundary-condition-transfer method for a shell-to-solid submodeling is fundamental for analyzing local or weak regions of a complex structure accurately. In this paper, a novel method is presented for transferring displacement boundaries based on hypothetical nodes. By considering the invariable volume of an element as a constraint, the interpolation through conventional methods using 6-degrees-of-freedom (DOFs) nodal translations and rotations is converted into a 3-DOF translational interpolation at the cut boundary of a submodel. To demonstrate this method, a radial basis function (RBF) was employed for interpolation. For validating the accuracy of the proposed method, a square plate with a hole under tensile and bending load were designed as examples. By considering global and local errors, three typical kernel functions with respect to mesh density ratios were analyzed to fix the optimal parameter in RBF. The examples showed that the proposed method significantly improves the accuracy in shell-to-solid submodeling problems compared to conventional solutions such as ANSYS. For structural analysis of a high-speed train car body under combined mechanical and aerodynamic loads, the submodeling method was implemented on the solid-element-based local model with a welding seam, with which a more detailed stress state was obtained compared with that computed by shell elements. The accurate and reliable results illustrate that the proposed method is the core for the global–local analysis of large complex structures, which also is used for the design and evaluation of the mechanical properties.
|
|
| 26. |
- Dou, Weiyuan, et al.
(författare)
-
A feature points-based method for data transfer in fluid-structure interactions
- 2022
-
Ingår i: International Journal of Mechanical Sciences. - : Elsevier BV. - 0020-7403 .- 1879-2162. ; 234
-
Tidskriftsartikel (refereegranskat)abstract
- For numerical simulations of fluid-structure interaction (FSI) problems, discretized meshes of different compu-tational domains do not have to match at the common interface. Data transfer via the interface is therefore significantly affecting the accuracy of FSI. Implementing data transfer between such pairwise non-matching meshes is challenging, as it is highly desirable to yield numerical accuracy using methods such as interpola-tion or projection. To further improve the data transfer accuracy for mesh-based approaches, this study proposes a feature points-based combined interpolation method by means of Simpson's rule, with which an appropriate weighting coefficient is determined. Moreover, radial basis function (RBF) is employed to perform the inter-polation of scattered data points. The proposed method is validated by a series of examples involving various non-matching mesh configurations in FSI problems. The numerical findings indicate that this method can further improve data transfer accuracy. Even for a critical case with large mesh ratio at the interface it can provide satisfying results.
|
|
| 27. |
- Enblom, Roger, et al.
(författare)
-
Industrial implementation of novel procedures for the prediction of railway wheel surface deterioration
- 2011
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 271:1-2, s. 203-209
-
Tidskriftsartikel (refereegranskat)abstract
- Adequate performance of the wheel-rail interface is essential for satisfactory operation of a railway system in terms of quality of service and maintenance effort. Pertinent requirements on efficiency tend to push the operation conditions towards higher loads and increased speed while the wheel-rail contact remains a small and highly stressed area. Dominating modes of deterioration due to high normal and tangential stresses are wear and rolling contact fatigue. Both kinds lead to surface material loss, in the former case as a slow rate profile geometry change with consequences to the dynamic performance and in the latter case different crack patterns and eventually spalling or shelling requiring reprofiling. In this paper the implementation of emerging technologies for the prediction of wheel surface deterioration in an engineering environment is summarised. Methods for the prediction of wear and profile geometry evolution as well as for the assessment of the risk for the onset of rolling contact fatigue are described. Example results from recent applications are given. In general it may be concluded that the implemented methods are becoming useful for the prediction of profile alterations, for instance hollow wear linked to conicity increase, and flange wear. The fatigue assessment methods are less mature and need further calibration but are still capable of indicating location and significance of risk for damage.
|
|
| 28. |
- Enblom, Roger, et al.
(författare)
-
Industrial implementation of novel railway wheel damage prediction procedures
- 2009
-
Ingår i: 8th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems.
-
Konferensbidrag (refereegranskat)abstract
- Adequate performance of the wheel-rail interface is essential for satisfactory operation of a railway system in terms of quality of service and maintenance effort. Pertinent requirements on efficiency tend to push the operation conditions toward higher loads and increased speed while the wheel-rail contact remains as a small and highly stressed area. Dominating modes of deterioration due to high normal and tangential stresses are wear and rolling contact fatigue. Both kinds lead to surface material loss, in the former case as a slow rate profile geometry change with consequences to the dynamic performance and in the latter case different crack patterns and eventually spalling or shelling requiring reprofiling.In this paper the implementation of emerging technologies for wheel damage prediction in an engineering environment is summarised. Methods for prediction of wear and profile geometry evolution as well as for assessment of the risk for onset of rolling contact fatigue are described. Example results from recent applications are given.In general it may be concluded that the implemented methods are becoming useful for prediction of profile alterations, for instance hollow wear linked to conicity increase and flange wear. The fatigue assessment methods are less mature and need further calibration but are still capable to indicate location and significance of risk for damage.
|
|
| 29. |
- Forsberg, Tobias, et al.
(författare)
-
Condition Monitoring of Train Ride Stability
- 2007
-
Ingår i: Proceedings of the 7th International Conference on Railway Bogies and Running Gears, BOGIE'07, Budapest, September 3-6, 2007. ; , s. 271-280
-
Konferensbidrag (refereegranskat)
|
|
| 30. |
- Fu, Bin, et al.
(författare)
-
Active suspension in railway vehicles: a literature survey
- 2020
-
Ingår i: Railway Engineering Science. - : Springer. - 2662-4745 .- 2662-4753. ; , s. 3-35
-
Tidskriftsartikel (refereegranskat)abstract
- Since the concept of active suspensions appeared, its large possible benefits has attracted continuous exploration in the field of railway engineering. With new demands of higher speed, better ride comfort and lower maintenance cost for railway vehicles, active suspensions are very promising technologies. Being the starting point of commercial application of active suspensions in rail vehicles, tilting trains have become a great success in some countries. With increased technical maturity of sensors and actuators, active suspension has unprecedented development opportunities. In this work, the basic concepts are summarized with new theories and solutions that have appeared over the last decade. Experimental studies and the implementation status of different active suspension technologies are described as well. Firstly, tilting trains are briefly described. Thereafter, an in-depth study for active secondary and primary suspensions is performed. For both topics, after an introductory section an explanation of possible solutions existing in the literature is given. The implementation status is reported. Active secondary suspensions are categorized into active and semi-active suspensions. Primary suspensions are instead divided between acting on solid-axle wheelsets and independently rotating wheels. Lastly, a brief summary and outlook is presented in terms of benefits, research status and challenges. The potential for active suspensions in railway applications is outlined.
|
|
| 31. |
- Fu, B., et al.
(författare)
-
Study on active wheelset steering from the perspective of wheel wear evolution
- 2022
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 60:3, s. 906-929
-
Tidskriftsartikel (refereegranskat)abstract
- Active wheelset steering promises an attractive cost–benefit ratio and is highly likely to be implemented in the future. Previous studies investigated the steering effect simply through a wear index like wear number. However, a wear index cannot predict how much the material removal on wheels can be reduced, and it is unable to reveal the wear pattern. This paper builds an iterative wear model to predict wheel wear evaluation under the presence of an active steering system. Three active steering schemes are proposed, and they are compared in terms of wheel wear evolution. To quantify the steering effectiveness, two factors are created to, respectively, evaluate economic impacts and satisfaction of three steering schemes. Finally, a simplified method based on traditional wear indices is compared with the established iterative wear calculation method to examine the applicability and tolerance of the simplified method.
|
|
| 32. |
- Fu, Bin, et al.
(författare)
-
Wheel Wear Evolution of Solid-Axle Wheelset with Active Steering
- 2022
-
Ingår i: ICRT 2021 - Proceedings of the 2nd International Conference on Rail Transportation. - Reston, VA : American Society of Civil Engineers (ASCE). ; , s. 24-32
-
Konferensbidrag (refereegranskat)abstract
- Active steering is an attractive technology to improve vehicle curving performance. It can reduce the track shift force and wear index in curves, but it is still unknown how much material removal across the wheel profile can be reduced and how it would affect the wheel wear evolution, which is crucial to motivate the implementation of active steering. This paper studies the wheel profile evolution under the presence of active steering. An iterative wear calculation approach is applied based on Archard's wear model. Two practical steering control strategies are proposed. The wheel wear simulations are performed in three different scenarios, considering different rail cants and proportions of curves. The simulation results reveal the wear pattern of the actively steered vehicle and verify the reduced material removal across the wheel profile especially on the wheel flange. The two control strategies are also compared and evaluated for the future application of the active steering system.
|
|
| 33. |
- Gao, Shigen, et al.
(författare)
-
High-Speed Trains Automatic Operation with Protection Constraints : A Resilient Nonlinear Gain-based Feedback Control Approach
- 2019
-
Ingår i: IEEE-CAA JOURNAL OF AUTOMATICA SINICA. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2329-9266. ; 6:4, s. 992-999
-
Tidskriftsartikel (refereegranskat)abstract
- This paper addresses the control design for automatic train operation of high-speed trains with protection constraints. A new resilient nonlinear gain-based feedback control approach is proposed, which is capable of guaranteeing, under some proper non-restrictive initial conditions, the protection constraints control raised by the distance-to-go (moving authority) curve and automatic train protection in practice. A new hyperbolic tangent function-based model is presented to mimic the whole operation process of high-speed trains. The proposed feedback control methods are easily implementable and computationally inexpensive because the presence of only two feedback gains guarantee satisfactory tracking performance and closed-loop stability, no adaptations of unknown parameters, function approximation of unknown nonlinearities, and attenuation of external disturbances in the proposed control strategies. Finally, rigorous proofs and comparative simulation results are given to demonstrate the effectiveness of the proposed approaches.
|
|
| 34. |
- Giossi, Rocco Libero, 1991-, et al.
(författare)
-
Active Modal Control of an Innovative Two-Axle Vehicle with Composite Frame Running Gear
- 2021
-
Ingår i: IAVSD 2021. - Cham : Springer Science and Business Media Deutschland GmbH. ; , s. 8-17
-
Konferensbidrag (refereegranskat)abstract
- Within the Shift2Rail projects Pivot2 and NEXTGEAR, an innovative Metro vehicle with single axle running gear and only one suspension step is proposed. A composite material running gear frame is developed to be used both as structural and as suspension element. The design with only one suspension step can significantly degrade the passengers ride comfort. Thus, active modal control is implemented both in lateral and vertical direction to increase the performance of the system. The running gear frame is modelled in Abaqus® as well as the carbody. Structural modes of both elements are implemented in SIMPACK®. A hydraulic actuator model is developed in Simscape®, where two pressure-controlled valves are used to control the pressure inside the chambers of a double acting hydraulic cylinder. A co-simulation environment is then established between SIMPACK® and Simulink®. The vehicle is running with speeds between 10 and 120 km/h. Active modal control makes it possible to maintain ride comfort levels of conventional bogie vehicles with this innovative single axle and single suspension step running gear, promising substantial weight savings of about 400 kg/m. The single axle running gear solution with active comfort control developed here can be an attractive alternative to bogies, providing reduced Life Cycle Costs.
|
|
| 35. |
- Giossi, Rocco Libero, 1991-, et al.
(författare)
-
Gain Scaling for Active Wheelset Steering on Innovative Two-Axle Vehicle
- 2020
-
Ingår i: Lecture Notes in Mechanical Engineering. - Cham : Springer International Publishing.
-
Konferensbidrag (refereegranskat)abstract
- Within the Shift2Rail project Run2Rail, an innovative single axle running gear with only one suspension step is proposed. A composite material frame shall be used both as structural and as suspension element. To improve curving performance active wheelset steering control is introduced. The selected control aims to minimize the longitudinal creepage by controlling the lateral wheelset position on the track. A two-axle vehicle is created in the MBS program SIMPACK and co-simulation is established with Simulink. The control strategy used is a simple PID control. A set of run cases with different curves and speeds is selected to verify the performance. The control gain optimal for high non-compensated lateral acceleration (NLA) tends to produce unstable results for low speeds. Control gain scaling is introduced based on vehicle speed and online estimation of the curvature. The proposed gain scheduling approach maintains the simple control formulation still solving the instability problem. Gain scheduling allows use of optimal control gains for all combinations of curve radii and vehicle speed and thereby taking the full advantage that the active wheelset steering brings to a vehicle with single axle running gears.
|
|
| 36. |
- Giossi, Rocco Libero, 1991-, et al.
(författare)
-
Improved curving performance of an innovative two-axle vehicle: a reasonable feedforward active steering approach
- 2020
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159.
-
Tidskriftsartikel (refereegranskat)abstract
- A mechatronic rail vehicle with reduced tare weight, two axles and only one level of suspension is proposed with the objective of reducing investment and maintenance costs. A wheelset to carbody connection frame in composite material will be used both as structural and as suspension element. Active control is introduced to steer the wheelsets and improve the curving performance. A feedforward control approach for active curve steering based on non-compensated lateral acceleration and curvature is proposed to overcome stability issues of a feedback approach. The feedforward approach is synthesised starting from the best achievable results of selected feedback approaches in terms of wheel energy dissipation and required actuation force. A set of 357 running cases (embracing 7 curves, 17 speeds per curve and 3 conicities) is used to design the controller. The controller is shown to perform well for conicity and track geometry variations and under the presence of track irregularities.
|
|
| 37. |
- Giossi, Rocco Libero, 1991-
(författare)
-
Mechatronic aspects of an innovative two-axle railway vehicle
- 2023
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Within the Shift2Rail research program the goals for a sustainable growth of the railway sector are set. Among these are substantial reduction of Life Cycle Costs, improved reliability and energy efficiency, the reductionof noise emissions, and the achievement of full interoperability of the rolling stock. Therefore, a new generation of running gear is envisioned.An innovative two-axle vehicle that can reduce weight, initial investmentand maintenance cost, and emissions is proposed for a metro line system. The vehicle proposed will have only one suspension step. To further reducethe weight and incorporate the otherwise missing anti-roll bar, a compositematerial connection frame is introduced. The two-axle configuration suffers from poor ride comfort, due to the lack of a second suspension step acting as filter, and from poor steering capability, due to the long distance between wheelsets. Active suspensions are therefore introduced to improve both ride comfort and steering capability.This Ph.D. thesis showcases the key activities undertaken during the developmentof the innovative vehicle, building a simulation framework where the vehicle can be virtually tested. Several modelling environments are used such as: SIMPACK for vehicle dynamics, Abaqus for finite elements modelling, Simscape for hydraulic physics simulations, and Simulink for control logic development. During the Ph.D. time two elements of the mechatronic vehicle have been designed and manufactured, i.e. the carbon fiber connection frame and the steering active suspension. The two components models have been experimentally validated and introduced into the simulation environment. A ride comfort and a wheelset steering control strategy have been designed to overcome the limitations introduced by the two-axle configuration. The proposed solutions aim at being applicable in the whole operational scenario of the innovative vehicle.The present work emphasises the possibility of introducing innovative mechatronic solutions as an alternative to standard bogie solutions aiming at reducing costs and emissions, blurring the boundaries between academic view and possible industrial applications.
|
|
| 38. |
- Giossi, Rocco Libero, 1991-, et al.
(författare)
-
Towards the realization of an innovative rail vehicle - active ride comfort control
- 2022
-
Ingår i: Control Engineering Practice. - : Elsevier BV. - 0967-0661 .- 1873-6939. ; 129
-
Tidskriftsartikel (refereegranskat)abstract
- The Shift2Rail project Pivot2 introduces an innovative metro vehicle with two single axle running gears with only one suspension step to reduce the vehicle's weight. A U-shaped connection frame is designed in Carbon Fibre Reinforced Polymer to further reduce weight and incorporate the anti-roll bar. Due to the poor ride comfort of the vehicle with standard passive dampers, all six dampers are replaced by hydraulic actuators. Modal control is applied and optimized with genetic algorithms. Despite the good improvements obtained, the weighted vertical acceleration remains above the acceptance level. Two modifications of modal control are studied, i.e., modal control with additional sensor, and blended control. Based on the frequency response of the results, it is proposed a low-pass filtered blended controller to neglect frame accelerations high frequency content. This last improves vertical comfort at the expenses of a more complex control system in comparison to modal control.
|
|
| 39. |
- Giossi, Rocco Libero, 1991-, et al.
(författare)
-
Wheel wear reduction of a mechatronic two-axle vehicle controlled with feedforward wheelset steering approaches
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The mechatronic vehicle developed within the Shift2Rail projects Run2Rail, Pivot, NEXTGEAR, and Pivot2 is evaluated with respect to wheel wear. The KTH wear model is used to determine the coefficients of Archard’s wear map to reproduce measured worn wheel profiles of the present vehicle running on Metro Madrid line 10. The same wear model is then used to evaluate the performance of the mechatronic vehicle controlled with two variants of a feedforward controller. The first one uses on-board measurements, while the second one is optimized using firefly optimisation algorithms assuming knowledge of the travelled track. The control strategy based on on-board measurements shows improvements above 60% in terms of lost wheel volume due to wear, compared to the standard bogie vehicle. The optimized controller reaches improvements above 70%. Good coherence is found between improvements predicted with the wear number and the ones achieved in terms of lost wheel volume.
|
|
| 40. |
- Hossein Nia, Saeed, 1983-
(författare)
-
An Investigation of the Iron-Ore Wheel Damages using Vehicle Dynamics Simulation
- 2014
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Maintenance cost is one of the important issues in railway heavy haul operations. For the iron-ore company LKAB, these costs are mainly associated with the reprofiling and changing of the wheels of the locomotives and wagons. The main reason for the wheel damages is usually surface initiated rolling contact fatigue (RCF) on the wheels.The present work tries to enhance and improve the knowledge of the vehicle-track interaction of the Swedish iron-ore freight wagons and locomotives used at Malmbanan. The study is divided into two parts. Firstly, it is tried to get into the roots of RCF using the simulation model of the iron ore wagon (Paper A). Secondly, the study is focused on predicting wear and RCF on the locomotive wheels also via a dynamic simulation model (Paper B).In the first paper, some key issues of the dynamic modelling of the wagons with three piece bogies are first discussed and then parameter studies are carried out to find the most important reasons of wheel damages. These parameter studies include track design geometry, track irregularities, wheel-rail friction level, cant deficiency and track stiffness. The results show a significant effect of the friction level on the amount of RCF risk.As the locomotive wheel life is much shorter than that of the wagons, LKAB has decided to change the locomotive wheel profile. Two final wheel profiles are proposed; however, one had to be approved for the field tests. In the second paper, the long term evolution of the two profiles is compared via wear simulation analysis. Also, the RCF evolution on the wheel profiles as a function of running distance is discussed. The process is first carried out for the current locomotive wheel profiles and the results are compared with the measurements. Good agreement is achieved. Finally, one of the proposed profiles is suggested for the field test because of the mild wear and RCF propagation.
|
|
| 41. |
- Hossein Nia, Saeed, 1983-, et al.
(författare)
-
Can Simulation Help to Find the Sources of Wheel Damages? : Investigation of Rolling Contact fatigue on the Wheels of a Three-Piece Bogie on the Swedish Iron ore Line via Multibody Simulation Considering Extreme Winter Condition
- 2013
-
Ingår i: Proceedings of the 10Th International Heavy Haul Association Conference IHHA. ; , s. 357-363
-
Konferensbidrag (refereegranskat)abstract
- The Swedish iron ore company LKAB uses freight wagon with three-piece bogie to transport iron ore from the mines in Kiruna and Malmberget to Luleå and Narvik. A simulation model of the freight wagon has been built at KTH Rail Vehicles using the Multibody simulation code GENSYS. The purpose is to investigate possible sources of rolling contact fatigue (RCF) of the wheels given the high level of damage, particularly in the winter.The wooden sleeper track has recently been replaced by a stiffer track with concrete sleeper. After the change, the frequency of RCF increased. Therefore, both track models are implemented. A parameter study is performed on vertical track stiffness and viscous damping regarding the seasonal variations of the track conditions. Another parameter study is carried out on the influence of the wheel-rail friction coefficient because in winter time the climate is very dry along most parst of the Swedish iron-ore line. The impact of new and worn wheel profiles on RCF is investigated. The wear number is calculated and compared with the RCF probability.The shakedown map is used to study the influence of an increase in track forces on RCF. It is shown that RCF happens on the tread of the inner wheels while negotiating curves below approximately 450 m radius. And in cold dry climate conditions when the wheel-rail friction coefficient significantly increases and when the wheel material behaves more brittle, the risk of RCF is significantly increased while the wear rate is not high enough to wear out the initiated cracks. It is proven that using concrete sleepers and vertically stiffer track might increase the track forces but it cannot be the main reason for severe RCF during winter.
|
|
| 42. |
- Hossein Nia, Saeed, et al.
(författare)
-
Fast Wear Calculation for Wheel Profile Optimization
- 2015
-
Ingår i: 10th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Colorado Springs, August 30 - September 3, 2015. - : 10th Contact Mechanics Conference.
-
Konferensbidrag (refereegranskat)
|
|
| 43. |
- Hossein Nia, Saeed, 1983-
(författare)
-
On Heavy-Haul Wheel Damages using Vehicle Dynamics Simulation
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Maintenance cost is one of the important issues in railway heavy-haul operations. In most of the cases, these costs are majorly referring to reprofiling and changing the wheels of the locomotives and the wagons. The main reason of the wheel damages is usually severe wear and/or surface initiated rolling contact fatigue (RCF).This work tries to enhance and improve the knowledge of the wheel wear and RCF prediction models using dynamic simulations. While most of the contents of this study can be generalised to other operational networks, this study is focused on the locomotives and wagons of the Swedish iron-ore company LKAB. The trains are operating on the approximately 500 km long IORE line from Luleå to Narvik in the north of Sweden and Norway respectively.Firstly, a literature survey of dynamic modelling of the wagons with various three-piece bogie types is presented. Then, with concentrating on the standard three-piece bogies, parameter studies are carried out to find out what the most important reasons of wheel damages are. Moreover, the long-term stability of wheel profiles of the IORE wagons is analysed. This is done by visualising the wear and RCF evolution on the wheel profiles over 150,000km of simulated running distance.Most of the calculations for the wagons are repeated for the locomotives. However, traction and braking are also considered in the simulation model and their effects on wheel damages are briefly studied. To improve the accuracy of the wheel damage analysis, a newly developed algorithm called FaStrip is used to solve the tangential contact problem instead of FASTSIM. The damage prediction model developed in the thesis is used to study the effects of increasing axle load, correcting the track gauge, limiting the electro-dynamic braking and using a harder wheel material on the wheel life. Furthermore, a new method is developed to predict the running distance between two consecutive reprofilings due to severe surface initiated fatigue. The method is based on shakedown analysis and laboratory tests.Most of the research works in wear calculation are limited to two approaches known as wear number and Archard methods. The correlation between these two methods is studied. The possibility of using the relation between the two methods for the wear calculation process is investigated mainly to reduce the calculation time for wheel profile optimisation models.
|
|
| 44. |
- Hossein Nia, Saeed, 1983-, et al.
(författare)
-
Prediction of RCF and Wear Evolution of Iron-Ore Locomotive wheels
- 2015
-
Ingår i: Wear. - : Elsevier. - 0043-1648 .- 1873-2577. ; 338-339, s. 62-72
-
Tidskriftsartikel (refereegranskat)abstract
- Locomotives for the iron ore line in northern Sweden and Norway have a short wheel life. The average running distance between two consecutive wheel turnings is around 40,000 km which makes the total life of a wheel around 400,000 km. The main reason of the short wheel life is the severe rolling contact fatigue (RCF). The train operator (LKAB) has decided to change the wheel profiles to get a better match with the rail shapes in order to decrease the creep forces leading to RCF. Two wheel profiles optimised via a genetic algorithm were proposed. They have, however, not been analysed for long term wear development. There is a risk that the optimised profiles might wear in an unfavourable way and after a while cause even higher RCF or wear than the original one. This study predicts wheel profile evolution using the uniform wear prediction tool based on Archard’s wear law. RCF evolution on the surface of the wheel profiles is also investigated. The impact of wear on polishing the wheel surface and avoiding the RCF cracks to propagate is considered via introducing a correction factor to the calculated RCF index. Traction and braking are also considered in the dynamic simulation model, where a PID control system keeps the speed of the vehicle constant by applying a torque on the loco wheels. The locomotives are also equipped with a flange lubrication system, therefore the calculations are performed both for lubricated and non-lubricated wheels. The simulation results for the wheel profiles currently in use, which are performed to validate the model and the simulation procedure, show a good agreement with the measurements. It is also concluded that the lubrication system partly does not perform as expected. Comparison between the proposed optimised profiles for their long term behaviour suggests that one of them produces less RCF and wear compared to the other one.
|
|
| 45. |
|
|
| 46. |
- Hossein Nia, Saeed, 1983-, et al.
(författare)
-
Prediction of rolling contact fatigue (RCF) for iron-ore locomotive wheels; comparison of an alternative contact algorithm with FASTSIM
- 2018
-
Ingår i: The Dynamics of Vehicles on Roads and Tracks. - : CRC Press/Balkema. - 9781138035713 ; , s. 835-840
-
Konferensbidrag (refereegranskat)abstract
- In this article, a model to estimate the evolution of surface initiated Rolling Contact Fatigue (RCF) is developed and applied to a heavy haul locomotive. To consider the changes in the wheel profile due to wear, a methodology based on Archard’s wear calculation theory is used. The method is based on the load collective concept, which determines a set of dynamic time-domain simulations as representative for the line. For RCF calculations a shakedown based theory is applied locally, using the FaStrip algorithm to estimate the tangential stresses instead of FASTSIM. The differences between the two algorithms regarding damage prediction models are studied. The differences are due to the accumulation of the FASTSIM error in the long-term process. The simulated crack locations and their angles are compared with a five-year field study and good agreements are achieved.
|
|
| 47. |
- Hossein Nia, Saeed, 1983-, et al.
(författare)
-
Predictive maintenance in railway systems : MBS-based wheel and rail life prediction exemplified for the Swedish Iron-Ore line
- 2022
-
Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; , s. 1-18
-
Tidskriftsartikel (refereegranskat)abstract
- A successful predictive maintenance strategy for wheels and rails depends on an accurate and robust modelling of damage evolution, mainly uniform wear and Rolling Contact Fatigue (RCF). In this work a life prediction framework for wheels and rails is presented. The prediction model accounts for wear, RCF, and their interaction based on the output from MBS simulations to calculate the remaining life of the asset, given in mileage for wheels and MGTs for rails. Once the model is calibrated, the proposed methodology can predict the sensitivity of the maintenance intervals against changes in operational conditions, such as changes in contact lubrication, track gauge, operating speeds, etc. The prediction framework is then used in two operational cases on the Swedish Iron-Ore line. The studied cases are, the analysis of wheel life for the locomotives, and the analysis of rail life for gauge widening scenarios. The results demonstrate the capabilities of the MBS-based damage modelling for predictive maintenance purposes and showcase how these techniques can set the path towards Digital Twins of railway assets.
|
|
| 48. |
- Hossein Nia, Saeed, 1983-, et al.
(författare)
-
Simulation-based evaluation of maintenance strategies from a life cycle cost perspective
- 2023
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. - 9780646865881 ; 532-533, s. 258-265
-
Tidskriftsartikel (refereegranskat)abstract
- A methodology that combines simulations of long-term mechanical degradation including maintenance interventions with an assessment of the associated socio-economic impact is proposed. This development responds to an urgent need within the railway sector to enable the evaluation of maintenance strategies from a LCC perspective. The functionality of the methodology is demonstrated in an investigation of rail grinding strategies for a curve on the Swedish Iron-ore line. The results indicate a reduction in LCC of 50% when using a harder rail material (R400HT) combined with annual rail grinding as compared to a softer rail material (R350LHT) and two grinding campaigns per year.
|
|
| 49. |
|
|
| 50. |
|
|
