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Gotowa bibliografia na temat „COMPUTATIONAL MODELLING OF RAIL WHEEL”

Autor: Grafiati

Data publikacji: 11 września 2023

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Artykuły w czasopismach na temat "COMPUTATIONAL MODELLING OF RAIL WHEEL"

Fajdiga, Gorazd, Matjaž Šraml i Janez Kramar. "Modelling of Rolling Contact Fatigue of Rails". Key Engineering Materials 324-325 (listopad 2006): 987–90. http://dx.doi.org/10.4028/www.scientific.net/kem.324-325.987.

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Rail dark spot defect, also termed as squat failure or shelling, is a rolling contact fatigue failure which occurs frequently on the high speed traffic railway rails. The main goal of this study is to develop a computational model for simulation of the squat phenomena on rails in rail-wheel contact. The proposed computational model consists of two parts: (i) Contact Fatigue Crack Initiation (CFCI) and (ii) Contact Fatigue Crack Propagation (CFCP). The results of proposed unified model enable a computational prediction of a probable number of loading cycles that a wheel-rail system can sustain before development of the initial crack in the rail, as well as the number of loading cycles required for a crack to propagate from initial to critical length, when the final fatigue failure (squat) can be expected to occur.

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An, Boyang, Jing Wen, Panjie Wang, Ping Wang, Rong Chen i Jingmang Xu. "Numerical Investigation into the Effect of Geometric Gap Idealisation on Wheel-Rail Rolling Contact in Presence of Yaw Angle". Mathematical Problems in Engineering 2019 (2.04.2019): 1–14. http://dx.doi.org/10.1155/2019/9895267.

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For a fast calculation of vehicle-track dynamics and wheel-rail contact mechanics, wheel-rail contact geometric gap is usually idealised in elliptic or nonelliptic form. These two idealisations deviate from the actual one if the lateral combined curvature within the contact patch is not constant or the yaw angle of wheelset exists. The influence of these idealisations on contact solution has not yet been deeply understood, and thus the accuracy of simplified contact modelling applied to vehicle-track dynamics and wheel-rail contact mechanics remains uncertain. This paper presents a numerical methodology to treat 3D wheel-rail rolling contact, in which the asymmetric geometric gap due to yaw angle is fully taken into account. The attention of this work is placed on investigating the effect of geometric gap idealisation on wheel-rail contact force, rolling contact solution, and wear distribution. It can help with the effective wheel-rail contact modelling on the computation of both vehicle-track dynamics and wheel-rail contact mechanics.

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Xu, Lei, Qiang Zhang, Zhiwu Yu i Zhihui Zhu. "Vehicle–track interaction with consideration of rail irregularities at three-dimensional space". Journal of Vibration and Control 26, nr 15-16 (14.01.2020): 1228–40. http://dx.doi.org/10.1177/1077546319894816.

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Modelling of vehicle–track interaction has long been a hot and interesting topic. In multibody dynamics based on force-equilibrium methods, Hertzian contact and creep theories have been applied in vehicle–track model constructions. In another aspect, the complementarity-based methods have also been widely used in establishing vehicle–track interaction, but still having drawbacks on characterization of wheel–rail contact geometry/creepage in three-dimensional space. In this study, we draw essences from methodologies of refined wheel–rail coupling models and energy-variational principle, and a model for vehicle–track three-dimensional interactions with inclusion of rail irregularity excitations is newly developed. This model possesses high accuracy compared with Hertzian contact, FastSim, and vehicle–track coupled model in the middle-low frequency domain, and also, the advantages in computational stability are possessed. In this model, the unevenness of rail irregularities at the three-dimensional space is preliminarily considered by taking a hypothesis of normal distribution and accordingly, the wheel–rail three-dimensional constraint equations are presented. Extensively, a series of numerical examples are shown to verify the effectiveness and engineering practicability of this model. Besides, the influence of rail three-dimensional irregularities on the dynamic performance of vehicle–track systems is further explored, which shows when the trochoid of the wheel–rail contact points changes rapidly, the additional inertial effects brought out by rail irregularities might exert great influence on wheel–rail forces.

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Dižo, Ján, Miroslav Blatnický, Jozef Harušinec i Andrej Suchánek. "Assessment of Dynamics of a Rail Vehicle in Terms of Running Properties While Moving on a Real Track Model". Symmetry 14, nr 3 (6.03.2022): 536. http://dx.doi.org/10.3390/sym14030536.

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Simulation computations represent a very effective tool for investigating operational characteristics and behaviours of vehicles without having a real product. The rail vehicles sector is typical, in that simulation computations including multibody modelling of individual vehicles (i.e., wagons) as well as entire trainsets are widely used. In the case of designing rail vehicles, running safety and ride comfort are two of the most important assessment areas. The presented work is focused on the research of the dynamical effects of a rail vehicle while running on a railway track created in a commercial multibody model. There is a lot of research focused on the investigation of dynamic performances while a rail vehicle is running on a flexible railway track. The real operation of a rail vehicle meets problems on track, where the stiffness-damping parameters of a railway track vary in transient sections (e.g., the exit of a tunnel). This work brings a contribution to research related to the assessment of the dynamic response of a rail vehicle on a chosen track section. A passenger railway vehicle is chosen as a reference multibody model. Simulation computations were performed for three different railway track models, i.e., for a rigid track model and for a flexible track model defined in two different manners. The stiffness-damping parameters of the rail vehicle are defined symmetrically in relation to the longitudinal axis of the vehicle, e.g., they are the same values for the left and right side. The centre of gravity is not located symmetrically, but it is partially shifted in the lateral direction. This can be observed in the results of wheel forces and their waveforms. There are evaluated values and waveforms of the vertical wheel forces, the lateral wheel forces and the derailment quotient. The obtained results have revealed the influence of the railway track formulation in the model on the output parameters.

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Baeza, L., F. J. Fuenmayor, J. Carballeira i A. Roda. "Influence of the wheel-rail contact instationary process on contact parameters". Journal of Strain Analysis for Engineering Design 42, nr 5 (1.07.2007): 377–87. http://dx.doi.org/10.1243/03093247jsa247.

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The rapid convergence of the tangential rolling contact parameters to their stationary values, combined with the high computational cost associated with calculations using instationary models, has meant that stationary models are usually employed in railway dynamics. However, the validity of stationary models when the applied contact conditions are subjected to rapid changes has not been sufficiently investigated. With the objective of deducing the effects of the evolution of the instationary process on the contact parameters, the tangential contact problem is solved for a set of reference conditions. For this purpose a calculation model is adapted, from which it is possible to analyse the evolution of the contact parameters when the forces exerted between rail and wheel are subjected to rapid changes. From the calculations made, situations impossible to simulate by means of stationary theories are obtained according to the frequency of variation in the forces, such as slip zones in the leading edge of the contact area and reverse contact (locally, the traction field is opposite to the direction of the external force transmitted to the contact).

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Zhao, Jing, Edwin A. H. Vollebregt i Cornelis W. Oosterlee. "EXTENDING THE BEM FOR ELASTIC CONTACT PROBLEMS BEYOND THE HALF-SPACE APPROACH". Mathematical Modelling and Analysis 21, nr 1 (26.01.2016): 119–41. http://dx.doi.org/10.3846/13926292.2016.1138418.

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The boundary element method (BEM) is widely used in fast numerical solvers for concentrated elastic contact problems arising from the wheel-rail contact in the railway industry. In this paper we extend the range of applicability of BEM by computing the influence coefficients (ICs) numerically. These ICs represent the Green’s function of the problem, i.e. the surface deformation due to unit loads. They are not analytically available when the half-space is invalid, for instance in conformal contact. An elastic model is proposed to compute these ICs numerically, by the finite element method (FEM). We present a detailed investigation to find proper strategies of FEM meshing and element types, considering accuracy and computational cost. Moreover, the effects of computed ICs to contact solutions are examined for a Cattaneo shift contact problem. The work in this paper provides a guidance to study fast solvers for the conformal contact.

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An, Boyang, Daolin Ma, Ping Wang, Jiayi Zhou, Rong Chen, Jingmang Xu i Dabin Cui. "Assessing the fast non-Hertzian methods based on the simulation of wheel–rail rolling contact and wear distribution". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, nr 5 (9.05.2019): 524–37. http://dx.doi.org/10.1177/0954409719848592.

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This paper aims at assessing several fast non-Hertzian methods, coupled with two wear models, based on the wheel–rail rolling contact and wear prediction. Four contact models, namely Kik-Piotrowski's method, Linder's method, Ayasse-Chollet's STRIPES algorithm and Sichani's ANALYN algorithm are employed for comparing the normal contact. For their tangential modelling, two tangential algorithms, i.e. FASTSIM and FaStrip, are used. Two commonly used wear models, namely the Archard (extended at the KTH Royal Institute of Technology) and USFD (developed by the University of Sheffield based on T-gamma approach), are further utilized for wear distribution computation. All results predicted by the fast non-Hertzian methods are evaluated against the results of Kalker's CONTACT code using penetration as the input. Since the two wear models adopt different expressions for calculating the wear performance, the attention of this paper is on assessing which one is more suitable for the fast non-Hertzian methods to utilize. The comparison shows that the combination of the USFD wear model with any of the fast non-Hertzian methods agrees better with CONTACT+USFD. In general, ANALYN+FaStrip is the best solution for the simulation of the wheel–rail rolling contact, while STRIPES+FASTSIM can provide better accuracy for the maximum wear depth prediction using the USFD wear model.

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Ramalho, A. "Wear modelling in rail–wheel contact". Wear 330-331 (maj 2015): 524–32. http://dx.doi.org/10.1016/j.wear.2015.01.067.

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Wu, Qing, Maksym Spiryagin, Peter Wolfs i Colin Cole. "Traction modelling in train dynamics". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 233, nr 4 (30.08.2018): 382–95. http://dx.doi.org/10.1177/0954409718795496.

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This paper presents five locomotive traction models for the purpose of train dynamics simulations, such as longitudinal train dynamics simulations. Model 1 is a look-up table model with a constant force limit to represent the adhesion limit without modelling the wheel–rail contact. Model 2 is improved from Model 1 by empirically simulating locomotive sanding systems, variable track conditions and traction force reduction due to curving. Model 3 and Model 4 have included modelling of the wheel–rail contact and traction control. Model 3 uses a two-dimensional locomotive model while Model 4 uses a three-dimensional locomotive. Model 5 is based on Model 2 and developed to simulate hybrid locomotives. Demonstrative simulations are presented for the case of longitudinal train dynamics. The results show that the consideration of locomotive sanding systems, variable track conditions and traction force reduction have evident implications on the simulated traction forces. There can be up to 30% difference in the simulated traction forces. Simulated traction forces by models that consider the wheel–rail contact are about 10–15% lower than those simulated by models without consideration of the wheel–rail contact. This is mainly due to the variable friction in the wheel–rail contact and conservative traction control schemes.

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Tao, Gongquan, Zefeng Wen, Xin Zhao i Xuesong Jin. "Effects of wheel–rail contact modelling on wheel wear simulation". Wear 366-367 (listopad 2016): 146–56. http://dx.doi.org/10.1016/j.wear.2016.05.010.

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Rozprawy doktorskie na temat "COMPUTATIONAL MODELLING OF RAIL WHEEL"

Shahzamanian, Sichani Matin. "Wheel-rail contact modelling in vehicle dynamics simulation". Licentiate thesis, KTH, Spårfordon, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-127949.

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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.

QC 20130911

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Pang, Tao, i tony_pang@hotmail com. "Studies on Wheel/Rail Contact Impact Forces at Insulated Rail Joints". Central Queensland University. Centre for Railway Engineering, 2008. http://library-resources.cqu.edu.au./thesis/adt-QCQU/public/adt-QCQU20080410.154708.

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To investigate the wheel/rail contact impact forces at insulated rail joints (IRJs), a three-dimensional finite element model and strain gauged experiments are employed and reported in this thesis. The 3D wheel/rail contact-impact FE model adopts a two-stage analysis strategy in which the wheel-IRJ railhead contact is first established in the static analysis and the results transferred to dynamic analysis for impact simulations. The explicit FE method was employed in the dynamic analysis. The Lagrange Multiplier method and the Penalty method for contact constraint enforcement were adopted for the static and dynamic analyses respectively. The wheel/rail contact-impact in the vicinity of the end post is exhibited via numerical examples from the FE modelling. The wheel/rail contact impact mechanism is investigated. The strain gauged experiments which consist of a lab test and a field test are reported. The signature of the strain time series from the field test demonstrates a plausible record of the dynamic responses due to the wheel/rail contact impact. By using the experimental data, both the static and the dynamic FE models are validated. It is found that the stiffness discontinuity of the IRJ structure causes a running surface geometry discontinuity during the wheel passages which then causes the impact in the vicinity of the end post. Through a series of sensitivity studies of several IRJ design parameters, it is shown that the IRJ performance can be effectively improved with optimised design parameters.

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Thompson, David John. "Wheel-rail noise : theoretical modelling of the generation of vibrations". Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277499.

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Shahzamanian, Sichani Matin. "On Efficient Modelling of Wheel-Rail Contact in Vehicle Dynamics Simulation". Doctoral thesis, KTH, Spårfordon, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-181691.

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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.

QC 20160202

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Enblom, Roger. "Simulation of Wheel and Rail Profile Evolution : Wear Modelling and Validation". Licentiate thesis, KTH, Aeronautical and Vehicle Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1754.

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Numerical procedures for reliable wheel and rail wearprediction are rare. Recent development of simulationtechniques and computer power together with tribologicalknowledge do however suggest computer aided wear prediction.The objective of the related research field at the RoyalInstitute of Technology (KTH) is to arrive at a numericalprocedure able to simulate profile evolution due to uniformwear to a degree of accuracy sufficient for application tovehicle dynamics simulation. Such a tool would be useful formaintenance planning as well as optimisation of the transportsystem and its components.

The research contribution accounted for in this thesisincludes, in addition to a literature review, refinement ofmethods applied to uniform wheel wear simulation by inclusionof braking and improvement of the contact model. Further atentative application to uniform rail wheel simulation has beenproposed and tested.

The first part addresses issues related to braking andwheel-rail contact conditions in the context of wheel wearsimulation. The KTH approach includes Archards wear modelwith associated wear maps, vehicle dynamics simulation andrailway network definition. In previous work at KTH certainvariations in operating conditions have been accounted forthrough empirically estimated average scaling factors. Theobjective of the current research is to be able to include suchvariations in the set of simulations. In particular theinfluence of disc braking and varying friction and lubricationconditions are investigated. Both environmental factors likemoist and contamination and deliberate lubrication need to beconsidered. As part of the associated contact analysis theinfluence of tangential elastic deformation of the contactingsurfaces on the sliding velocity has been separatelyinvestigated and found to be essential in case of partial slipcontact conditions.

In the second part validation of the improvements related towheel wear simulation is addressed. Disc braking has beenincluded in the simulation set and a wear map for moist contactconditions based on recent tribometer tests has been draftedand tested. It has been shown that the previously used brakingfactor accounts for the combination of the contributions fromsurface elasticity and braking. Good agreement withmeasurements from the Stockholm commuter service is achieved.It is concluded that the model improvements accounted for aresufficient for adequate simulation of tread wear but thatfurther development of the flange / gauge corner contactmodelling may be needed.

In the final part a procedure for simulation of rail wearand corresponding profile evolution has been formulated. Asimulation set is selected defining the vehicles running on thetrack to be investigated, their operating conditions, andcontact parameters. Several variations of input data may beincluded together with the corresponding occurrenceprobability. Trial calculations of four non-lubricated curveswith radii from 303 m to 802 m show qualitatively reasonableresults in terms of profile shape development and difference inwear mechanisms between gauge corner and rail head. The wearrates related to traffic tonnage are however overestimated. Itis believed that model refinements in terms of environmentalinfluence and contact stress calculation are useful to improvethe quantitative results.

QC 20100531

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Wickramasinghe, Munidasa Widhana Pathiranage Isuru Udara. "Investigation of surface ratchetting due to rail/wheel contact". Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/67800/1/Munidasa%20Widhana%20Pathiranage%20Isuru%20Udara_Wickramasinghe_Thesis.pdf.

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This project advances the knowledge of rail wear and crack formation due to rail/wheel contact in Australian heavy-haul railway lines. This comprehensive study utilised numerous techniques including: simulation using a twin-disk test-rig, scanning electron microscope particle analysis and finite element modeling for material failure prediction. Through this work, new material failure models have been developed which may be used to predict the lifetime and reliability of materials undergoing severe contact conditions.

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Öhnander, Fred. "An Attempt Towards FE-Modelling of Fracture Propagation in Railway Wheels". Thesis, KTH, Spårfordon, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-234468.

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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.
Efterfrågan på högre hastigheter och tyngre axelbelastningar för godståg leder till högre krafter på järnvägshjulen som i sin tur leder till ökade spänningar på och under ytan vid hjul-räl-kontakten. Med tiden induceras slitage på hjulen som följaktligen leder till höga underhållskostnader och i vissa fall olyckor. Förmågan att förutse utvecklingen av hjulprofiler på grund av enhetligt slitage har visats kunna ske med en noggrann precision under de flesta driftsförhållanden. Dessa slitagemodeller bygger på slitagekoefficienter, och eftersom de vanligtvis inte är giltiga under realistiska driftsförhållanden är modellerna i allmänhet kalibrerade mot verkliga händelseförlopp för att justera koefficienterna från testförhållandena till realistiska smörjförhållanden. Detta tekniska tillvägagångssätt kan vara användbart vid prognos av slitage i system där material och kontaktförhållanden inte varierar. När man addresserar materialutveckling inriktad på att reducera specifika skadelägen är emellertid tillvägagångssättet av begränsad användning eftersom de erhållna slitagekoefficienterna inte är direkt relaterade till materialegenskaper. Därför har försök gjorts till att utveckla fysikaliska sprickbildningsmodeller som relateras till kontaktförhållanden och materialegenskaper. Syftet har varit att erhålla viktig information om var en spricka initieras och hur den fortskrider. I det långa loppet är det även av stor vikt att kunna erhålla information om hur en materialpartikel avlägsnas från kontaktytan. Studier för denna typ av modeller har gjorts på 70- och 80-talet i huvudsak med stift- och skivexperiment men har inte använts inom det specifika området för hjul-räl-kontakt. Avhandligen ingår i FR8RAIL-projektet som arrangeras av det europeiska järnvägsinitiativet Shift2Rail. Literaturstudier har varit grunden för avhandlingen för att få väsentlig insikt i frakturmekanik och andra relaterade områden. De fysiska sprickbildningsmodellerna har konstrueras i FE-mjukvaran Abaqus med XFEM som implementering. För 2D-modellen initieras sprickan överst vid den implanterade imperfektionen när friktionskoefficienten är och propagerar uppåt några få element. För initieras sprickan på högra ytgränsen där tryckfördelning och friktionskraft appliceras. Utbredningsvinkeln för sprickan ökar relativt till ytan då friktionskoefficienten ökar. Sprickan för 3D-modellen breder ut sig mer jämfört med 2D-modellen överst vid imperfektionen då . Sprickan initieras på samma ytplats som för 2D-modellen vid . Sprickbildningen är dock obefintlig på grund av konvergensproblem. De konstruerade FE-modellerna är initiala steg mot att analysera sprickutbredningen och närbesläktade fenomen för ett godstågs järnvägshjul i detalj. I slutet av avhandlingen ger de förenklade modellerna huvudsakligen information om sprickinitiering, utbredning och dess mönster. Ytterligare justeringar och förbättringar kan ske efter denna första fas i syfte att eliminera felmarginalerna. På lång sikt kan slutligen helt integrerande modeller med ytterligare implementeringar såsom detaljerad mikrostruktur för kontaktförhållandena, oelastiskt materialbeteende och kompletta tredimensionella modeller användas.
FR8RAIL

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Lundberg, Oskar. "On the influence of surface roughness on rolling contact forces". Doctoral thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-193935.

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Road vehicle tyres, railway wheels and ball bearings all generate rolling contact forces which are transferred within a finite area of contact between the rolling element and the substrate. Either it is visible or not for the human eye, a certain degree of roughness is always present on the contacting surfaces and it influences the generation of both vertical and lateral contactforces. The purpose of this investigation is to enhance the understanding and modelling of the influence from small-scale surface roughness on the generation of rolling contact forces. To this end, a computationally efficient method to include roughness-induced contact nonlinearities in the dynamic modelling of rolling contacts is proposed. The method is implemented in a time domain model for vertical wheel–track interaction to model rolling-induced rail vibrations, showing good agreement with measurements. Furthermore, a test rig is developed and used for the investigation of tyre–road rolling contact forces. Detailed studies are performed on the influence of substrate roughness on the resulting contact forces for a tyre tread block which is rolling at different operating conditions. The choice of substrate as well as the rolling velocity and the slip ratio is observed to have significant influence on the resulting friction coefficient. For high slip ratios, stick–slip oscillations appear, exhibiting frequency content which is largely dependent on the choice of substrate. The outcomes of this study can potentially be used to improve future tyre–road contacts with respect to wear, traction and noise generation.

QC 20161013

Centre for Eco2 Vehicle Design

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Giner, Navarro Juan. "Advances Techniques for Time-Domain Modelling of High-Frequency Train/Track Interaction". Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/90637.

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[EN] The aim of the present Thesis is to develop models for the study of very high-frequency phenomena associated with the coupling dynamics of a railway vehicle with the track. Through these models, this Thesis intends to address squeal noise as a particular case of rolling noise when the train negotiates a small radius curve. Wheel/rail interaction is the predominant source of noise emission in railway operations. Rolling contact couples the wheel and the rail through a very small area, characterised by strongly non-linear and non-steady state dynamics that differentiates rolling noise from any other noise problem. Wheel/rail contact problem is studied based on Kalker's variational theory and the local falling behaviour of the coefficient of friction is introduced by means of a regularisation of Coulomb's law. Its implementation shows that the influence of the falling friction on the creep curves can be assumed negligible, thus rolling contact is finally modelled using a constant coefficient of friction. Flexibility is introduced in railway substructures through the Finite Element (FE) method in order to cover the high-frequency range. This work adopts a rotatory wheelset model that takes computational advantage of its rotational symmetry. It also develops a cyclic flexible rail model that fixes the translational contact force in a spatial point of the mesh through a technique called Moving Element (ME) method. A modal approach is used to reduce significantly the number of degrees of freedom of the global problem and a diagonalisation technique permits to decouple the resulting modal equations of motion in order to increase the computational velocity of the time integrator. Simulations in curving conditions in the time domain are carried out for constant friction conditions in order to study if the proposed interaction model can reproduce squeal characteristics for different curve radii and coefficients of friction.
[ES] El objetivo de la presente Tesis es desarrollar modelos para el estudio de fenómenos de muy alta frecuencia asociados a la dinámica acoplada de un vehículo ferroviario con la vía. A través de estos modelos, esta Tesis pretende abordar el fenómeno de los chirridos como un caso particular de ruido de rodadura en condiciones de curva cerrada. La interacción rueda/carril es la fuente predominante de ruido en las operaciones ferroviarias. El contacto es el responsable del acoplamiento entre la rueda y el carril a través de un área muy pequeña caracterizada por una dinámica fuertemente no lineal y no estacionaria. El problema de contacto rueda/carril se estudia mediante la teoría variacional de Kalker y la caída local del coeficiente de fricción se introduce por medio de una regularización de la ley de Coulomb, que muestra que su influencia sobre las curvas de fluencia se puede despreciar. Como consecuencia, el coeficiente de fricción se considera constante. La flexibilidad se introduce en las subestructuras ferroviarias a través del método de los Elementos Finitos (EF) para cubrir el rango de las altas frecuencias. La Tesis adopta un modelo de eje montado rotatorio que toma ventaja computacional de su simetría rotacional. También desarrolla un modelo de carril flexible y cíclico que fija la fuerza de contacto en un punto espacial de la malla mediante el método de los Elementos Móviles (EM). Se utiliza un enfoque modal para reducir significativamente el número de grados de libertad del problema global; las ecuaciones de movimiento resultantes en coordenadas modales se desacoplan mendiante una técnica de diagonalización para aumentar la velocidad computacional del integrador temporal. Las simulaciones en condiciones de curva en el dominio del tiempo se llevan a cabo en condiciones de fricción constante con el objetivo de estudiar si el modelo de interacción propuesto puede reproducir las características del chirrido en curva para diferentes radios de curva y coeficientes de fricción.
[CAT] L'objectiu de la present Tesi és desenvolupar models per a l'estudi de fenòmens de molt alta freqüència associats amb la dinàmica acoblada d'un vehicle ferroviari amb la via. Aquests models permeten simular el soroll de rodament encara que, en particular, aquest treball es proposa abordar el fenomen del soroll grinyolant produït quan el tren negocia un radi de curvatura estret. La interacció roda/carril és la font predominant de l'emissió de soroll en les operacions ferroviàries. El contacte acobla la roda i el carril a través d'una àrea molt reduïda que es caracteritza per una dinàmica fortament no lineal i no estacionària. El problema de contacte roda/carril s'estudia mitjançant la teoria variacional de Kalker i el descens local del coeficient de fricció s'introdueix per mitjà d'una regularització de la llei de Coulomb, què demostra que la seua influència en les corbes de fluència es pot suposar insignificant. Per tant, s'utilitza un coeficient de fricció constant per a modelar el contacte. La flexibilitat s'introdueix en les subestructures de ferrocarril a través del mètode d'Elements Finits (EF) per tal de cobrir el rang d'alta freqüència. La present tesi adopta un model d'eix muntat rotatori que s'aprofita de la seua la simetria rotacional per a augmentar la eficiència computacional. També desenvolupa un model de carril flexible i cíclic que fixa la força de contacte en un punt espacial de la malla a través del mètode dels Elements Mòbils (EM). S'empra un enfocament modal per reduir significativament el nombre de graus de llibertat del problema global, al temps que s'implementa una tècnica diagonalització que permet desacoblar les equacions modals de moviment per a augmentar la velocitat computacional de l'integrador temporal. Les simulacions en les condicions de corba en el domini del temps es duen a terme per a condicions de fricció constant per tal d'estudiar si el model d'interacció proposat pot reproduir les característiques del soroll grinyolant per a diferents radis de corba i coeficients de fricció.
Giner Navarro, J. (2017). Advances Techniques for Time-Domain Modelling of High-Frequency Train/Track Interaction [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90637
TESIS

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SINGH, DEVENDRA. "COMPUTATIONAL STRESS ANALYSIS OF RAIL-WHEEL MODEL OF INDIAN RAILWAYS". Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14637.

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ABSTRACT Wheel-rail contact analysis is one of the most standout problems in the modeling and analysis of railway vehicles. The wheel-rail interaction is an exceptional part of rail-vehicle progress as it accounts for the capacity of freight wagon and is being considered the most critical parameter for the freight traffic wagons on the railway tracks. In this thesis, the static response of the wheel on a rail is analyzed by modelling and analyzing the geometries of standard section of Rail and wheel through the softwares Creo parametric 2.0 and Ansys 15.0 for calculating the stresses between the Rail-wheel contact region. An analytical approach for calculating the tangent modulus has been drafted during the selection of material and its properties using the Ramberg Osgood Equation. The Hertzian contact theory gives the expression for the maximum contact shear stress value at the point of contact between the rail and the wheel. To validate the value of contact shear stresses founded in this thesis, responses of the assembled model using Ansys 15.0 are compared with the Hertzian approach as well as with the Hertzian stress calculator. Then it has been found that all the three maximum contact shear stresses achieved by different methods are less than the standard limiting values of maximum contact shear stresses in accordance to the Indian Railway Standard. Finally the effects of the results have been studied for the essence of analysis. Maximum contact shear stress between Rail-wheel is found to be 25.5 kg/mm2, 24.63 kg/mm2, 23.55 kg/mm2 by Ansys 15.0, Hertzian theory and Hertzian stress calculator respectively for 90 UTS rail of UIC 60 kg section and all are less than the limiting value of contact stress which is 27.0 kg/mm2 for 90 UTS rails and it was the prime objective of thesis. The thesis is divided into six chapters. The first chapter describes the introductory part of Indian Railways and importance of Freight traffic, followed by the scope and domain of the freight traffic. The next chapter gives an insight regarding the Railway track, rails and wheels, apart from this the chapter also focuses on theory of contact stresses as well as bending stresses. Chapter three, describes the processing of modelling of Rail UIC 60 kg (90 UTS) and wheel of BOXN standard, followed by the fourth chapter which accounts for the computational static analysis of the assembled model of rail and wheel. Chapter five, represents the result validation of contact shear stress and compares it with the limiting values in accordance to Indian Railway Standard. Chapter six delineates the conclusion.

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Części książek na temat "COMPUTATIONAL MODELLING OF RAIL WHEEL"

Kalker, J. J. "Computational Contact Mechanics of the Wheel-Rail System". W Rail Quality and Maintenance for Modern Railway Operation, 151–64. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-015-8151-6_13.

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Ienaga, Saki, Yoshiaki Terumichi, Kazuhiko Nishimura i Minoru Nishina. "Numerical and Experimental Study on Contact Force Fluctuation Between Wheel and Rail Considering Rail Flexibility and Track Conditions". W Computational Methods in Applied Sciences, 239–57. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-30614-8_11.

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Liu, Binbin, i Stefano Bruni. "Comparison of Wheel-Rail Contact Modelling in Multibody System Online Simulation". W Lecture Notes in Mechanical Engineering, 694–703. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-38077-9_81.

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Meijaard, J. P. "Continuous and Discontinuous Modelling of the Contact between Wheel Flange and Rail". W Topics in Applied Mechanics, 119–26. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-2090-6_12.

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Kukėnas, Vladas, Boris Kharitonov, Mikhail Levinzon, Raimondas Jasvičius i Viačeslav Petrenko. "Modelling and Analysis of a Rolling Wheel with “Inconsistent Abrasion” in Contact with the Rail". W TRANSBALTICA XII: Transportation Science and Technology, 120–30. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94774-3_12.

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Sheng, Xiaozhen, Gong Cheng i David J. Thompson. "Modelling Wheel/Rail Rolling Noise for a High-Speed Train Running on a Slab Track". W Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 613–20. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70289-2_67.

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Pieringer, A., i W. Kropp. "A Time-Domain Model for Coupled Vertical and Tangential Wheel/Rail Interaction - A Contribution to the Modelling of Curve Squeal". W Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 221–29. Tokyo: Springer Japan, 2012. http://dx.doi.org/10.1007/978-4-431-53927-8_26.

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Franklin, F. J., J. E. Garnham, C. L. Davis, D. I. Fletcher i A. Kapoor. "The evolution and failure of pearlitic microstructure in rail steel – observations and modelling". W Wheel–Rail Interface Handbook, 311–48. Elsevier, 2009. http://dx.doi.org/10.1533/9781845696788.1.311.

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Streszczenia konferencji na temat "COMPUTATIONAL MODELLING OF RAIL WHEEL"

Spiryagin, Maksym, Qing Wu, Chris Bosomworth, Colin Cole, Mark Hayman i Ingemar Persson. "Wheel-Rail Contact Modelling for Locomotive Traction Control System Studies". W 2020 Joint Rail Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/jrc2020-8108.

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Abstract Recent locomotive traction studies have been extensively focused on the development of wheel-rail contact models for application inside multibody software products to compute results which can be further used in the prediction of track damage indexes. These models are quite sufficient, but they have a significant disadvantage of slow computational speed. In order to use the same locomotive models for traction studies, a new concept of the model was studied. The main difference from existing models is the developed normal task approach that provides a transition from non-Hertzian to Hertzian contact patches and this innovation was validated against the results obtained in a parallel computation test implemented inside of the wheel-rail coupling based on the Extended Contact library. The test was performed with a multibody locomotive model running on tangent track. The first implementation of the developed wheel rail-coupling has been tested in a parallel mode with the Extended Contact library on a full mechatronic model of a locomotive and the results compared against each other. Discussion on the further development is provided.

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Myśliński, A., i A. Chudzikiewicz. "Wear modelling in elasto-plastic wheel-rail contact problems". W 8th European Congress on Computational Methods in Applied Sciences and Engineering. CIMNE, 2022. http://dx.doi.org/10.23967/eccomas.2022.296.

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Evtukh, E. S., i G. A. Neklyudova. "Computational modelling of the railway wheel dynamics when rolling through a rail gap". W PROCEEDINGS INTERNATIONAL CONFERENCE “PROBLEMS OF APPLIED MECHANICS”. AIP Publishing, 2021. http://dx.doi.org/10.1063/5.0047333.

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Landström, Eric Voortman, Tore Vernersson i Roger Lundén. "Improved modelling of tread braked wheels using an advanced material model". W EuroBrake 2022. FISITA, 2022. http://dx.doi.org/10.46720/eb2022-rlb-003.

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"Railway freight wagons are often braked using mechanical friction brakes in the form of tread brakes that act directly on the tread of the wheels which at the same time are in rolling contact with the rail. The tread brakes should provide sufficient braking capacity of the train for both normal service braking and extreme braking conditions. This braking system requires a minimum of components and is therefore a low-cost and low-maintenance choice for the industry. However, the utilisation of the wheel as a friction-heated component, also worn by the brake, comes at a cost in form of complex loading situations in which elevated temperatures resulting from braking are interacting with the wheel-rail rolling contact loads. To safely employ the brakes in all situations, accurate knowledge about how the materials interact during these loading situations is required. Studies have shown that temperatures above 500 °C are to be expected, and cases with temperatures more than 600 °C may occur. At such high temperatures, the normally employed ER7 wheel steel is significantly weakened and shows sign of rapid material breakdown by, e g, spheroidization of the pearlitic material structure. To account for these effects, computational models capable of simulation of the complex thermomechanical behaviour are a must. As part of our recent research, a novel viscoplastic material model has been calibrated against isothermal low cycle fatigue tests and against thermomechanical experiments based upon actual in-service scenarios for a range of temperatures, showing good results both for wheel rim material and for wheel web material. The novel material model constitutes a further enhancement of previously developed models that were calibrated solely by use of isothermal materials testing. The objective of the present study is to further investigate and examine the capabilities and accuracy of the novel material model when employed in detailed braking simulation. To achieve this, an axisymmetric finite element model of a standard freight wheel during tread braking is used to assess the performance of the material model. The finite element model accounts, in a simplified fashion, for residual stresses introduced by the rim hardening process at wheel manufacturing and for variations in material properties based on typical hardness values on a wheel cross section. A range of braking situations are assessed to achieve different loads and temperatures, mainly by mimicking downhill braking at constant speed for a prolonged time period. The numerical results are then compared to known experimental quantities, including residual stresses in the wheel rim as well as rim deflections. The results are also compared to the pertinent European standard on technical approval for forged wheels. Additionally, the same exercise is repeated for previous material models, calibrated merely by isothermal data, as a point of comparison with the thermomechanically calibrated one. The results show that the material model predicts realistic material behaviour for a wide range of braking situations. Compared with previous models, a general improvement is seen, suggesting that the newer features of the material model contribute substantially to more accurate modelling of the processes occurring in the wheel during high temperature tread braking. "

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Fisette, Paul, Krzysztof Lipiński i Jean-Claude Samin. "A Multibody Loop Constraints Approach for Modelling Cam/Follower Devices: Application in Mobile Robotics". W ASME 1999 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/detc99/vib-8246.

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Abstract This paper proposes a formulation for modelling mechanisms with cam/follower type of contact using a multibody approach in relative coordinates. The proposed approach is inspired from the wheel/rail contact model developed in (Fisette, Samin, 1994) but in the present case, possible intermittent contact between the cam and the follower is considered, for generality purposes. Loop kinematic constraints are introduced to satisfy tangent and punctual contact as long as the bodies lean against each other. The effective presence (or not) of the contact is governed by the sign of the normal constraint force which can be computed thanks to the Lagrange multipliers technique. The above-mentioned option to kinematically constraint the bodies in their “contact phase” unavoidably leads to shift from one model to another when a contact disappears (or conversely reappears). Indeed, this increases (or decreases) the number of degrees of freedom of the current system. The control of the variable partitioning is thus absolutely necessary and is all the more complex that practical applications can contain several pairs of bodies in intermittent contact. As regards the applications, a comparison with another multi-body formalism and an experimental validation are discussed at first. Then, the modelling and simulation of universal wheels of an omnimobile mobile robot, developed in our Division, are proposed. The latter model represents a quite original application of the proposed multibody formulation. Computations are now in progress to analyse the complete behaviour of the robot, including control performances.

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Anyakwo, Arthur, Crinela Pislaru i Andrew Ball. "Modelling Rail Vehicle Dynamics Using a Novel 2D Wheel-Rail Contact Model". W 2013 European Modelling Symposium (EMS). IEEE, 2013. http://dx.doi.org/10.1109/ems.2013.78.

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Sun, Yu, Sen Zhang, Yu Guo i Liming Zhu. "Effect of Wheel-Rail Contact Modelling on Vehicle Dynamics Simulation". W Second International Conference on Rail Transportation. Reston, VA: American Society of Civil Engineers, 2022. http://dx.doi.org/10.1061/9780784483886.007.

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Stonier, Russel J., Sita Kuppa, Peter J. Thomas i Colin Cole. "Fuzzy Modelling of Wagon Wheel Unloading Due to Longitudinal Impact Forces". W ASME/IEEE 2005 Joint Rail Conference. ASME, 2005. http://dx.doi.org/10.1115/rtd2005-70034.

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Mutswatiwa, Lovejoy, Celestin Nkundineza i Mehmet A. Güler. "Modelling the Effect of Track Stiffness Variation on Wheel Rail Interaction Using Finite Element Method". W 2021 Joint Rail Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/jrc2021-58519.

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Abstract For predictive maintenance purpose, wheel and rail wear evolution models have been developed based on wheel rail contact force calculations. These models are known to assume the wheel rotating on a rigid rail. However recent developments have shown that the flexibility of the track plays an important role in wear evolution. On the other hand, vertical track stiffness variation along the track is known to exist and to affect the track flexibility. The present research work investigates the influence of non-uniform track modulus on the wheel rail contact forces using elasto-plastic explicit dynamic Finite Elements (FE). The FE model is composed of a quarter car model running on a rail supported by three cross-ties. The modulus of elasticity of the cross-ties is calibrated to produce the total track modulus of the railroad track infrastructure. Non-uniformity of the track is modeled by assigning distinct elasticity moduli to the cross-ties. The instantaneous contact physical parameters are extracted from FE models repetitively for various cross-tie modulus ratios. The results show that increase in cross-tie modulus variation results in increased fluctuation amplitudes of wheel-rail contact parameters such as force, stress and contact area. This effect leads to changes of the rate of material removal on the wheels and rails. This research work intends to incorporate the spatial variation of the railroad track stiffness into rail vehicle wheel and track wear prediction models.

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Bosso, N., A. Gugliotta i N. Zampieri. "RTCONTACT: An Efficient Wheel-Rail Contact Algorithm for Real-Time Dynamic Simulations". W 2012 Joint Rail Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/jrc2012-74044.

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Determination of contact forces exchanged between wheel and rail is one of the most important topics in railway dynamics. Recent studies are oriented to improve the existing contact methods in terms of computational efficiency on one side and on the other side to develop more complex and precise representation of the contact problem. This work shows some new results of the contact code developed at Politecnico di Torino identified as RTCONTACT; this code, which is an improvement of the CONPOL algorithm, is the result of long term activities, early versions were used in conjunction with MBS codes or in Matlab® environment to simulate vehicle behaviour. The code has been improved also using experimental tests performed on a scaled roller-rig. More recently the contact model was improved in order to obtain a higher computational efficiency that is a required for the use inside of a Real Time process. Benefit of a Real Time contact algorithm is the possibility to use complex simulation models in diagnostic or control systems in order to improve their performances. This work shows several comparisons of the RTCONTACT contact code respect commercial codes, standards and benchmark results.

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