Academic literature on the topic 'Wheel / rail contact'

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Journal articles on the topic "Wheel / rail contact"

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Chen, Zhi Wei, Linan Li, Shi Gang Sun, and Jun Long Zhou. "Wheel-Rail Multi-Point Contact Method for Railway Turnouts." Applied Mechanics and Materials 97-98 (September 2011): 378–81. http://dx.doi.org/10.4028/www.scientific.net/amm.97-98.378.

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A calculation method of wheel-rail multi-point contact based on the elastic contact model is introduced. Moreover, the simulation calculation of vehicles passing through branch lines of No.18 turnouts is carried out. The result showed that the acute change of wheel-rail normal force caused by the transfers of wheel-rail contact point between two rails can be avoid by wheel-rail multi-point contact method, and the transfers of wheel-rail normal force between two rails is smoother. The validity of wheel-rail multi-point contact method is verified.
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Ma, He, Jun Zhang, and Xiu Juan Zhang. "The Calculation and Analysis for the Independent Wheels of Tramcar." Applied Mechanics and Materials 577 (July 2014): 297–300. http://dx.doi.org/10.4028/www.scientific.net/amm.577.297.

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The wheel/rail profiles in different wear stages are measured using the apparatus of wheel-rail profile. The 3D elastic-plastic FEM contact models are established for the straight line and curves, in which attack angle is considered. Contact problems between the wheels in different wear stages and the worn rail are studied. Contact area, normal contact force, and equivalent Von Mises stress of different cases are analyzed. The obtained results show that the maximum equivalent Von Mises stress reduces and tends to be steady with the independent wheel wearing. Widening the track gauge can have an influence on the variation of wheel wear positions and the wear rules between wheel and rail. When the wheel with a certain attack angle contacts with rail, the maximum equivalent Von Mises stress appears at the contact region between the flange and rail side. The influence of attack angle on the wear between the wheel and rail is quite serious. It is very important to do the research for the further optimization and design of the wheel/rail profiles.
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Kumar, S., and S. P. Singh. "Heavy Axle Load Wheel-Rail Contact Stresses and Their Tread-Crown Curvature Relationships." Journal of Engineering for Industry 111, no. 4 (November 1, 1989): 382–87. http://dx.doi.org/10.1115/1.3188776.

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This paper presents a theoretical/design analysis of wheel-rail contact stresses and geometries for U.S. freight cars of 70, 95, 100, and 125 ton freight capacities operating on various crown rails. After discussing various types of rail stresses, it is pointed out that the contact stresses are the major factor and the only parameter that enables a designer to improve or optimize the rail life and performance. In order to determine the most suitable diameters for the heavier cars, an engineering lower bound analysis of the contact has been completed. It uses in a two-dimensional Hertzian analysis, the field information of well worn-out wheel and rail contacts which are almost rectangular and of 1 in. width. The lower engineering bound values of maximum normal contact stresses for the 100 and 125 ton cars using wheels of diameters from 33 to 42 in. are given. This stress for the current 100 ton car with 36 in. diameter wheels is 98.35 ksi. To approach this value for the 125 ton car it is necessary to use 42 in. diameter wheels which is strongly recommended for the U.S. railroads. A Hertz theory based analysis of the contact stresses with varying wheel diameter, tread profile radius and rail crown radius for the 70, 95, 100, and 125 ton cars has been presented. Using the field information that the difference in radii of curvature of worn wheel and rail is approximately 5 in., choice of radii of rail and wheel profile curvatures is made so that the design radii difference is always 5 in. or more. Wheel diameter and wheel profile radius ranges used for this analysis were 33 to 44 in. and 15 to 35 in., respectively. The rail crown radius range was 10 to 30 in. It was concluded that a rail crown radius of 15 to 20 in. and wheel tread profile radius of 22 to 30 in. are good initial ranges for further analysis of design.
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Kumar, S., and S. P. Singh. "Rail Head Geometry, Rail Rolling and Wheel-Rail Contact Tilting Analysis for Heavy Axle Loads." Journal of Engineering for Industry 111, no. 4 (November 1, 1989): 375–81. http://dx.doi.org/10.1115/1.3188775.

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This paper presents analytical considerations which are important to design a rail head for reducing rail damage due to heavy axle loads. There are two important parameters of design of rail crown: (1) the wheel tread rail crown contact stress and (2) the contact tilt angle called the β angle. Contact should not be allowed to move out of the rail crown. Analysis of lateral oscillations of new and worn wheel sets shows that they do not impose an engineering constraint on the choice of rail crown radius. Rail rolling on curves due to lateral creepage forces is however of great importance in rail loading and stresses. The point of contact location is significantly affected by such roll. For the two commonly used rails, 132 RE and 136 RE, this roll results in the contact moving to the part of the rail head with radius of 1 1/4 in. Such movement of the contact also develops rapidly when hollowed worn wheels roll on flattened worn rails. It is pointed out that this condition results in forces higher than the wheel load and stresses more than twice the value developed when the contact is within the rail crown and that this is most likely responsible for many of the rail failure problems including cracking, shelling, and fractures. A design analysis of rail crown including Hertzian contact and rail twist considerations shows that none of the three current rails analyzed satisfy the criteria developed for good rail head design. A suitable ellipitical crown should prove better. Finally a systems approach to rail wheel interaction with a number of design recommendations is given.
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Mazov, Yuriy Nikolaevich, Aleksey Alekseevich Loktev, and Vyacheslav Petrovich Sychev. "Assessing the influence of wheel defects of a rolling stockon railway tracks." Vestnik MGSU, no. 5 (May 2015): 61–72. http://dx.doi.org/10.22227/1997-0935.2015.5.61-72.

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Transfer of the load from the wheels on the rail occurs at a very small area compared with the size of the wheels and rails. The materials near this site have a very large voltage. Determination of contact stresses is complicated by the fact that the magnitude of these stresses in the rails under actually revolving wheel load exceeds the yield and compressive strength of modern rail steel. We should note that the metal of the rail head, experiencing contact stresses, especially when the location of the pads is closer to the middle of the rail head, works in the conditions close to the compression conditions, and therefore can withstand higher voltage without plastic deformation than the standard compressible sample. But, as a rule, the observed hardening of the metal in the zone of contact stresses and lapping at the edges of the rail head indicates the presence of plastic deformation and, consequently, higher stresses in the wheel-rail contact zone than the yield strength of the metal rail even in the conditions of its operation in the rail head.The use of the design equations derived on the basis of the Hertz theory for metal behavior in elastic stage, is valid. The reason is that each individual dynamic application of wheel loads on the rail is very short, and the residual plastic deformation from the individual loads of the pair of wheels on the rail is actually small. This elastic-plastic deformation of the rail becomes visible as a result of gradual gaining of a missed tonnage of rails and wheels respectively. Irregularities on the running surface of the wheels are of two types. The most common are the so-called continuous bumps on the wheel, when due to the uneven wear of rail the original shape of the wheel across the tread surface distorts. But nowadays, more and more often there occur isolated smooth irregularities of the wheel pairs, due to the increased wear of the wheel because of the stopping and blocking of wheels of the vehicles - slides (potholes), etc.The motion of the wheels with irregularities on the surface of the rail leads to vertical oscillation of the wheel, resulting in the forces of inertia, which is an additional load on the rail. In case of movement of the wheel with isolated roughness on the tread surface of the slide there is a strike, having a very large additional impact on the rail. Such attacks can cause kinked rails, especially in the winter months when there is increased fragility of rail steel, because of lowered temperatures. This is an abnormal phenomenon and occurs relatively rarely, at a small number of isolated irregularities on a wheel of the rolling stock. As correlations connecting the contact force and local deformation in the interaction of the wheel-rail system, we use the quasi-static Hertz’s model, linear-elastic model and two elastoplastic contact models: Alexandrov-Kadomtsev and Kil’chevsky. According to the results of Loktev’s studies ratios of the contact Hertz’s theory are quite suitable for modeling the dynamic effects of wheel and rail for speeds up to 90 km/h for engineering calculations. Since the contact surface is homogeneous and isotropic, the friction forces in the contact zone are not taken into account, the size of the pad is small compared to the dimensions of the contacting bodies and characteristic radii of curvature of the undeformed surfaces, the contacting surfaces are smooth.When train is driving, the position of the wheelset in relation to the rails varies con- siderably, giving rise to different combinations of the contact areas of the wheel and rail. Even assuming constant axial load the normal voltage will vary considerably because of the differences in the radii of curvature of the contacting surfaces of these zones. Thus, the proposed method allows evaluating the influence of several types of wheel defects on the condition of the rail and the prospects of its use in the upper structure of a railway track on plots with different speed and traffic volumes. Also the results can be used to solve the inverse of the considered problems, for example, when designing high-speed highways, when setting the vehicle speed and axle load, and the solution results are the parameters of the defects, both wheelsets and the rails, in case of which higher require- ments for the safe operation of railways are observed.
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Wei, Kai, Xin Xiao, and Yu De Xu. "Rail Pre-Grinding on Shanghai-Nanjing PDL and its Effect on Wheel-Rail Contact Geometry." Advanced Materials Research 779-780 (September 2013): 660–63. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.660.

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The paper tests the rail profiles of Shanghai-Nanjing PDL after its rail pre-grinding. The grinding values are counted, which shows that the grinding mainly occurs on the inner side of rail top, ranging from 0 to 1.26mm. Wheel-Rail Contact Geometry is also analyzed. Results shows that after pre-grinding, the wheel-rail contact points concentrate to the center of rail top, and it is good for rail wear control. But the rolling radius difference decreases and it weakens the rails ability of return the wheels position.
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Quan SUN, Yan, Maksym SPIRYAGIN, Colin COLE, and Dwayne NIELSEN. "WHEEL–RAIL WEAR INVESTIGATION ON A HEAVY HAUL BALLOON LOOP TRACK THROUGH SIMULATIONS OF SLOW SPEED WAGON DYNAMICS." Transport 33, no. 3 (October 2, 2018): 843–52. http://dx.doi.org/10.3846/16484142.2017.1355843.

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Heavy haul railway track infrastructure are commonly equipped with balloon loops to allow trains to be loaded/unloaded and/or to reverse the direction of travel. The slow operational speed of trains on these sharp curves results in some unique issues regarding the wear process between wheels and rails. A wagon dynamic system model has been applied to simulate the dynamic behaviour in order to study the wheel–rail contact wear conditions. A wheel–rail wear index is used to assess the wear severity. The simulation shows that the lubrication to reduce the wheel–rail contact friction coefficient can significantly reduce the wear severity. Furthermore, the effects of important parameters on wheel–rail contact wear including curve radius, wagon speed and track superelevation have also been considered.
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Ma, Xiaochuan, Ping Wang, Jingmang Xu, and Rong Chen. "Effect of the vertical relative motion of stock/switch rails on wheel–rail contact mechanics in switch panel of railway turnout." Advances in Mechanical Engineering 10, no. 7 (July 2018): 168781401879065. http://dx.doi.org/10.1177/1687814018790659.

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In order to enable the vehicle to change among the tracks, the stock and switch rails are separated and provided with different rail resilience levels on the baseplate in the railway turnout switch panel. Therefore, there will be vertical relative motion between stock/switch rails under wheel loads, and the relative motion will change the combined profile of stock/switch rails and consequently affect the wheel–rail contact mechanics. A method is developed in this article to investigate the effect of the relative motion of stock/switch rails on the wheel–rail contact mechanics along the railway turnout switch panel. First, the possible rigid wheel–rail contact points, called primary and secondary stock/switch rail contact points, are calculated based on the trace line method; second, the actual contact points are determined by the presented equations; finally, the distribution of wheel–rail contact forces on the stock/switch rails is obtained based on the continuity of interface displacements and forces. A numerical example is presented in order to investigate the effect of the relative motion of stock/switch rails on the wheel–rail contact points, stresses, and forces, and the results are presented and discussed.
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Unitsky, Anatoli E., Aliaksandr S. Khlebus, Elena A. Ivanova, Aliaksandr E. Shashko, and Michael I. Tsyrlin. "Simulation of the contact pair “wheel-rail” of the experimental design of the flexible rail in the lightweight tracks of the uST string transport system." Modern Transportation Systems and Technologies 8, no. 4 (December 24, 2022): 107–25. http://dx.doi.org/10.17816/transsyst202284107-125.

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Rationale: Development of string rails with low weight per meter and high-performance characteristics that determine durability, wear resistance, reliable grip of vehicle wheels to the rail rolling surface is a vital task. Objective: to investigate impact of the geometric parameters of the steel wheel and the flexible string rail with a polymer coating on the performance characteristics; to choose the most optimal parameters of the contact pair wheel-rail. Methods: The calculation was made using the ANSYS finite element analysis software package. Results: in order to reduce the level of contact pressures, it is more expedient to lower the load on the wheel or increase the width of the contact, rather than to increase the radius of the wheel; the most optimal is the contact pair, where the modulus of elasticity of the polymer rail head is equal to the modulus of elasticity of the wheel material, that is, materials similar in elasticity are used in the contact pair.
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Magel, Eric, and Joe Kalousek. "Designing and assessing wheel/rail profiles for improved rolling contact fatigue and wear performance." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 231, no. 7 (June 1, 2017): 805–18. http://dx.doi.org/10.1177/0954409717708079.

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A quick survey of wheel and rail profiles used around the world reveals a huge range of options. Wheels come in cylindrical, conical, and concave variations, while rails range in shape from a very flat 14 in. (350 mm) head radius to a tightly crowned 6 in. (150 mm) head radius. The rationale for implementing one or the other is often institutional inertia—a strong tendency to continue doing what has been done in the past. But the impacts of wheel and rail profiles on the performance of the vehicle/track interaction are large and the decision should not be made lightly. Unfortunately, there are few well-matched “off-the-shelf” solutions from the existing commercially available profiles, such that new rails and wheels often suffer early failures or infant mortality. Through examples and case studies, this paper discusses the significant role that wheel and rail profiles play with respect to performance and safety and makes the case for wheel and rail profiles specifically suited to the needs of each railway. Various techniques for assessing the performance of systems of wheels and rails are reviewed and discussed.
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Dissertations / Theses on the topic "Wheel / rail contact"

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Smith, Lindsey. "Rolling contact fatigue in wheel-rail contact." Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438385.

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Zhu, Yi. "Adhesion in the wheel-rail contact." Doctoral thesis, KTH, Tribologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-133342.

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To attract more customers and compete with other modes of transportation, railway transport needs to ensure safety, punctuality, high comfort, and low cost; wheel–rail adhesion, i.e., the transmitted tangential force in the longitudinal direction during driving and braking, plays an important role in all these aspects. Adhesion needs to be kept at a certain level for railway operation and maintenance. However, wheel−rail contact is an open system contact. Different contaminants can present between the wheel and rail surfaces, forming a third-body layer that affects the adhesion. Prediction of wheel–rail adhesion is important for railway operations and research into vehicle dynamics; however, this prediction is difficult because of the presence of contaminants. This thesis deals with wheel–rail adhesion from a tribological perspective. The five appended papers discuss wheel–rail adhesion in terms of dry conditions, lubricated conditions, leaf contamination, iron oxides, and environmental conditions. The research methodologies used are numerical modelling, scaled laboratory experiments, and field tests. The research objective is to understand the mechanisms of the adhesion loss phenomenon.  A numerical model was developed to predict wheel–rail adhesion based on real measured 3D surfaces. Computer simulation indicates that surface topography has a larger impact on lubricated than on dry contacts. Plastic deformation in asperities is found to be very important in the model. Ball-on-disc tests indicate that water can give an extremely low adhesion coefficient on smooth surfaces, possibly due to surface oxidation. Investigation of lubricated contacts at low speed indicates that oil reduces the adhesion coefficient by carrying a normal load, while adhesion loss due to water depends on the surface topography, water temperature, and surface oxidation. A field investigation indicates that leaves reduce the friction coefficient because of the chemical reaction between leaves and bulk materials. The thickness of the surface oxide layer was found to be an essential factor determining adhesion reduction. Pin-on-disc experiments found a transition in the friction coefficient with regard to the relative humidity, due to a trade-off between the water molecule film and the hematite on the surface.

QC 20131031

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Galas, Radovan. "Friction Modification within Wheel-Rail Contact." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-367508.

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Předložená disertační práce se zabývá experimentálním studiem modifikátorů tření a maziv pro temeno kolejnice, které jsou aplikovány do kontaktu kola a kolejnice za účelem optimalizace adheze a redukce hluku. Hlavním cílem práce bylo objasnit vliv aplikovaného množství a složení těchto látek na adhezi v kontaktu. Hlavní pozornost byla věnována zejména potencionálním hrozbám souvisejících s kriticky nízkou adhezí, která může nastat po aplikaci těchto látek. Experimentální studium probíhalo v laboratorních i reálných podmínkách, konkrétně v tramvajovém provozu. V případě laboratorních experimentů byl využit komerční tribometr a dvoudiskové zařízení umožňující simulovat průjezd vozidla traťovým obloukem. Kromě samotné adheze bylo při experimentech sledováno také opotřebení a míra hluku. Výsledky ukázaly, že maziva pro temeno kolejnice jsou schopna poskytovat požadované třecí vlastnosti, nicméně jejich chování je silně závislé na aplikovaném množství. V případě předávkování kontaktu dochází ke kriticky nízkým hodnotám adheze, které vedou k výraznému prodloužení brzdné dráhy. V případě modifikátorů tření bylo ukázáno, že chování těchto látek je výrazně ovlivněno odpařováním základního média. Výsledky také ukázaly, že nadměrné množství částic pro modifikaci tření může způsobit kriticky nízké hodnoty adheze. U obou výše zmíněných typů produktů byl prokázán pozitivní vliv na míru opotřebení a míru poškození povrchu, zatímco významná redukce hluku byla dosažena pouze v případech, kdy došlo ke značnému poklesu adheze. V závěru této práce jsou uvedena doporučení pro další výzkumné aktivity v této oblasti.
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Pang, Tao, and 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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Jon, Sundh. "On wear transitions in the wheel-rail contact." Doctoral thesis, KTH, Maskinkonstruktion (Avd.), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11563.

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Wear transitions in the wheel–rail contact are of increasing interest since the general trend in railway traffic is toward increased velocities and axle loads. Curving increases the risk of flanging, causing the contact to change from an almost pure rolling wheel tread–rail head contact to more of a sliding wheel flange–rail gauge contact on the high rail in curves. Under wheel flange–rail gauge contact conditions, wear transitions to severe or catastrophic wear will occur if the contact is improperly lubricated. Such a transition is the most undesirable transition in the wheel–rail contact, as it represents a very expensive operating condition for railway companies. The contact conditions responsible for this transition are very severe as regards sliding velocity and contact pressure, and thus place high demands on both the lubricant and the wheel and rail materials. The focus of this thesis is on the transitions between different wear regimes in a wheel–rail contact. Wear is discussed both in traditional tribological terms and in terms of the categories used in the railway business, namely mild, severe and catastrophic wear. Most of the work was experimental and was performed at the Royal Institute of Technology (KTH), Department of Machine Design. The effects of contact pressure, sliding velocity, and type of lubricant have been investigated, producing results that resemble those of other studies presented in the literature. The absence of research relating to the wheel flange–rail gauge contact is addressed, and it is concluded that a lubricant film must be present on rails in curves to prevent severe or catastrophic wear. The formulation of this lubricant can further increase its wear- and seizure-preventing properties. To obtain a deeper understanding of wear transitions, methods such as airborne particle measurement and electron microscopy have been used. Paper A presents the test methodology used to detect seizure and discusses the wear-reducing influence of free carbon in highly loaded contacts. Paper B presents the testing of seizure-initiating conditions for a range of environmentally adapted lubricants applied to wheel and rail materials; a transient pin-on-disc test methodology was used for the testing. Paper C presents the use of pin-on-disc methodology to study the wear-reducing effects of a wide range of lubricants. The best performing lubricant was a mineral oil containing EP and AW additives. Paper D relates wear rates and transitions to airborne particles generated by an experimentally simulated wheel–rail contact. The airborne particles generated varied in size distribution and amount with wear rate and mechanism. Paper E relates additional analysis techniques, such as FIB sectioning, ESCA analysis, airborne particle measurements, and SEM imaging of airborne wear particles, to the contact temperature.
QC 20100721
Samba 6
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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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Martin, Michael. "The Effect of Geometrical Contact Input to Wheel-Rail Contact Model." Thesis, KTH, Spårfordon, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-239735.

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Wheel-rail contact is an important aspect of railway, the forces transferred between the wheel and rail are the one that guide, brake, or accelerate the train, and that is why the understanding of the contact between wheel and rail is an interesting research topic. In this master thesis wheel-rail contact model named ANALYN is used to see the effect of the different geometrical input, like undeformed distance, relative longitudinal curvature, and relative lateral curvature calculation affect the contact patch estimation formed at the wheel-rail contact.  In the process, a geometrical contact search code is made to find the contact point between wheel and rail for certain lateral displacement, yaw angle, and roll angle of the wheelset. The codes used to calculate the three geometrical inputs are also prepared, with two methods are prepared for each input. The results that generated from combination of the geometrical contact search and geometrical input preparation are used as the input to ANALYN. The results showed that different geometrical input calculations do affect the shape of the contact patch, with the calculation of lateral curvature being the most important since it affects the shape of the contact patch greater than other geometrical inputs. It is also shown that taking yaw angle into account in the contact search will affect the shape of the contact patch.
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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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Zhu, Yi. "Adhesion in the wheel-rail contact under contaminated conditions." Licentiate thesis, KTH, Tribologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48441.

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Railway vehicles require a certain level of adhesion between wheel and rail to operate efficiently, reliably, and economically. Different levels of adhesion are needed depending on the vehicle running conditions. In the wheel tread–railhead contact, the dominant problem is low adhesion, as low adhesion on the railhead negatively affects railway operation: on one hand, the vehicle will lose traction resulting in delay when driving on low-adhesion tracks; on the other hand, low adhesion during deceleration will extend the braking distance, which is a safety issue. This thesis examines the influence of several contaminants, i.e., water, oil, and leaves, on the adhesion in the wheel tread–railhead contact. This study will improve our knowledge of the low-adhesion mechanism and of how various contaminants influence adhesion. The thesis consists of a summary overview of the topic and three appended papers (A–C). Papers A and B focus mainly on water and oil contamination examined using two methods, numerical simulation and lab testing. In paper A, real measured wheel and rail surfaces, low- and high-roughness surfaces, along with generated smooth surfaces are used as input to the numerical model for predicting the adhesion coefficient. Water-lubricated, oil-lubricated, and dry contacts are simulated in the model. In the research reported in paper B, scaled testing using a mini traction machine (MTM) was carried out to simulate the wheel–rail contact under lubricated conditions. Two types of disc surfaces of different roughnesses were run at different contact pressures and temperatures. A stylus machine and atomic force microscopy (AFM) were used to measure the surface topography. A study of leaf contamination on the railhead surface, based on field testing, is presented in paper C. Railhead surface samples were cut and the friction coefficient was measured on five occasions over the course of a year. Electron spectroscopy for chemical analysis (ESCA) and glow discharge optical emission spectrometry (GD-OES) were used to detect the chemical composition of the leaf-contamination layer on the railhead surface. The main conclusion of the thesis is that different contaminants reduce the adhesion coefficient in different ways. Oil reduces the adhesion coefficient by carrying the normal force due to its high viscosity. Water can reduce the adhesion coefficient to different degrees depending on the surface topography and water temperature. The mixture of an oxide layer and water contamination may have an essential impact. A leaf-formed blackish layer causes low adhesion by means of a chemical reaction between the leaves and bulk material. The thickness of the friction-reducing oxide layer predicts the friction coefficient and the extent of leaf contamination.
QC 20111123
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Zhou, Yongji. "System-on-chip accelerator of wheel-rail contact laws." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531591.

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Books on the topic "Wheel / rail contact"

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(Firm), Knovel, ed. Wheel-rail interface handbook. Boca Raton, FL: CRC Press, 2009.

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Bosso, Nicola, Maksym Spiryagin, Antonio Gugliotta, and Aurelio Somà. Mechatronic Modeling of Real-Time Wheel-Rail Contact. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36246-0.

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Bosso, Nicola. Mechatronic Modeling of Real-Time Wheel-Rail Contact. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013.

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L, Grassie S., ed. Mechanics and fatigue in wheel/rail contact: Proceedings of the Third International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Cambridge, U.K. July 22-26, 1990. Amsterdam: Elsevier, 1991.

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Association, International Heavy Haul. Guidelines to best practices for heavy haul railway operations: Wheel and rail interface issues. Virginia Beach, Va: International Heavy Haul Association, 2001.

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International Conference on Contact Mechanics and Wear of Rail/Wheel Systems (3rd 1990 Cambridge, UK). Papers presented at the ThirdInternational Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Cambridge, UK, July 22-26, 1990. Edited by Dowson Duncan. Lausanne: Elsevier Sequoia, 1991.

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International Conference on Contact Mechanics and Wear of Rail/Wheel Systems (4th 1994 Vancouver, Canada). Papers presented at the 4th International Conference on Contact Mechanics and Wear of Rail-Wheel Systems, Vancouver, Canada, July 24-28, 1994. Edited by Kalousek J. Amsterdam: Elsevier, 1996.

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L, Gladwell G. M., Ghonem H. 1947-, and Kalousek Joseph, eds. Contact mechanics and wear of rail/wheel systems II: Proceedings of the international symposium held at the University of Rhode Island, Kingston, R.I., July 8-11, 1986. Waterloo, Ont: University of Waterloo Press, 1987.

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Cellar, Horst. Untersuchung des Dämpfungsverhaltens der Schlupfstelle zwischen Rad und Schiene. Mülheim/Ruhr: Kirnberg-Verlag, 1989.

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Isaev, Igorʹ Petrovich. Problemy st͡s︡eplenii͡a︡ koles lokomotiva s relʹsami. Moskva: "Mashinostroenie", 1985.

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Book chapters on the topic "Wheel / rail contact"

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Knothe, Klaus, and Sebastian Stichel. "Modeling of Wheel/Rail Contact." In Rail Vehicle Dynamics, 33–79. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-45376-7_3.

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Bosso, Nicola, Maksym Spiryagin, Antonio Gugliotta, and Aurelio Somà. "Review of Wheel-Rail Contact Models." In Mechatronic Modeling of Real-Time Wheel-Rail Contact, 5–19. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36246-0_2.

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Bosso, Nicola, Maksym Spiryagin, Antonio Gugliotta, and Aurelio Somà. "Contact Model." In Mechatronic Modeling of Real-Time Wheel-Rail Contact, 55–71. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36246-0_5.

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Marques, Filip, Hugo Magalhães, Joao Pombo, Jorge Ambrósio, and Paulo Flores. "Contact Detection Approach Between Wheel and Rail Surfaces." In New Trends in Mechanism and Machine Science, 405–12. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-55061-5_46.

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Kalker, J. J. "Computational Contact Mechanics of the Wheel-Rail System." In 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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True, Hans. "Dynamics of Railway Vehicles and Rail/Wheel Contact." In Dynamical Analysis of Vehicle Systems, 75–128. Vienna: Springer Vienna, 2009. http://dx.doi.org/10.1007/978-3-211-76666-8_2.

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Bosso, Nicola, Maksym Spiryagin, Antonio Gugliotta, and Aurelio Somà. "Real-Time Simulation of the Contact Model." In Mechatronic Modeling of Real-Time Wheel-Rail Contact, 73–89. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36246-0_6.

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Bosso, Nicola, Maksym Spiryagin, Antonio Gugliotta, and Aurelio Somà. "Introduction." In Mechatronic Modeling of Real-Time Wheel-Rail Contact, 1–4. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36246-0_1.

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Bosso, Nicola, Maksym Spiryagin, Antonio Gugliotta, and Aurelio Somà. "Roller Rigs." In Mechatronic Modeling of Real-Time Wheel-Rail Contact, 21–35. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36246-0_3.

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Bosso, Nicola, Maksym Spiryagin, Antonio Gugliotta, and Aurelio Somà. "Design of Scaled Roller Rigs." In Mechatronic Modeling of Real-Time Wheel-Rail Contact, 37–54. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36246-0_4.

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Conference papers on the topic "Wheel / rail contact"

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Chen, Yung-Chuan, Jao-Hwa Kuang, Li-Wen Chen, Jiang-Che Shin, and Sing-You Lee. "Wheel-Rail Thermal Contact on Rail Corrugation During Wheel Braking." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-79859.

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This paper uses the finite element method to investigate the effect of rail corrugation on the wheel-rail thermal contact pressure and temperature distributions during wheel braking. Contact elements are used to simulate the contact between a wheel and a rail. Various friction coefficients, wavelengths and amplitudes of corrugated rails as well as braking times are considered in this study. The results indicate that, in the wheel-rail contact area, the rail corrugation affects the contact pressure and temperature distributions significantly. A modified equation with time-dependent heat partition factor is proposed to predict the rail surface temperature distribution for rails with smooth surfaces. Simulation results show that the proposed equation works very well. The results also indicate that the corrugated rail can lead to a wavy temperature distribution on the rail surface. Also, a smaller corrugated rail amplitude results in a higher maximum temperature near the trough region and a lower one near the crest region.
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Tunna, John. "Rolling Contact Fatigue in Passenger and Freight Railroads." In 2010 Joint Rail Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/jrc2010-36039.

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Rolling Contact Fatigue (RCF) can occur on wheels and rails in passenger and freight railroads. It can be a significant cost driver, and, if left untreated, it may lead to derailments. Tangential wheel-rail forces, creepage and contract stress are shown to be the causes of RCF. Improved vehicle curving performance and optimized wheel and rail profiles are shown to have benefits. Methods of managing RCF are preventive rail grinding and wheel turning. Improved wheel and rail materials can also have benefits. The paper includes examples of rail and wheel RCF in both passenger and freight railroads. References are given to other papers for further reading on this subject.
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Cummings, Scott M., Patricia Schreiber, and Harry M. Tournay. "Parametric Simulation of Rolling Contact Fatigue." In ASME 2008 Rail Transportation Division Fall Technical Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/rtdf2008-74012.

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Simulations of dynamic vehicle performance were used by the Wheel Defect Prevention Research Consortium (WDPRC) to explore which track and vehicle variables affect wheel fatigue life. A NUCARS® model was used to efficiently examine the effects of a multitude of parameters including wheel/rail profiles, wheel/rail lubrication, truck type, curvature, speed, and track geometry. Results from over 1,000 simulations of a loaded 1,272 kN (286,000-pound) hopper car are summarized. Rolling contact fatigue (RCF) is one way that wheels can develop treads defects. Thermal mechanical shelling (TMS) is a subset of wheel shelling in which the heat from tread braking reduces a wheel’s fatigue resistance. RCF and TMS together are estimated to account for approximately half of the total wheel tread damage problem [1]. Other types of tread damage can result from wheel slides. The work described in this paper concerns pure RCF, without regard to temperature effects or wheel slide events. Much work has been conducted in the past decade in an attempt to model the occurrence of RCF on wheels and rails. The two primary methods that have gained popularity are shakedown theory and wear model. The choice of which model to use is somewhat dependent on the type of data available, as each model has advantages and disadvantages. The wear model was selected for use in this analysis because it can account for the effect of wear on the contacting surfaces and is easily applied to simulation data in which the creep and creep force are available. The findings of the NUCARS simulations in relation to the wear model include the following: • Degree of curvature is the single most important factor in determining the amount of RCF damage to wheels; • The use of trucks (hereafter referred to as M-976) that have met the Association of American Railroads’ (AAR) M-976 Specification with properly maintained wheel and rail profiles should produce better wheel RCF life on typical routes than standard trucks; • In most curves, the low-rail wheel of the leading wheelset in each truck is most prone to RCF damage; • While the use of flange lubricators (with or without top of rail (TOR) friction control applied equally to both rails) can be beneficial in some scenarios, it should not be considered a cure-all for wheel RCF problems, and may in fact exacerbate RCF problems for AAR M-976 trucks in some instances; • Avoiding superelevation excess (operating slower than curve design speed) provides RCF benefits for wheels in cars with standard three-piece trucks; • Small track perturbations reduce the overall RCF damage to a wheel negotiating a curve.
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Sugiyama, Hiroyuki, and Yoshihiro Suda. "Hybrid Contact Search Algorithm for Wheel/Rail Contact Problems." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68588.

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In this investigation, the on-line and off-line hybrid contact algorithm for modeling wheel/rail contact problems is developed based on the elastic contact formulation. In the tabular contact search used in existing specialized railroad vehicle dynamics codes, contact points are predicted using an assumption of rigid contacts. For this reason, the contact points can be different from those predicted by the on-line based contact search used in general elastic contact formulations. The difference in the contact point becomes significant when flange contacts that have large contact angles are considered. In the hybrid algorithm developed in this investigation, the off-line tabular search is used for treating tread contacts, while the on-line iterative search is used for treating flange contacts. By so doing, a computationally efficient procedure is achieved while keeping accurate predictions of contact points on the wheel flange. Furthermore, the use of the proposed hybrid algorithm can eliminate the use of time-consuming on-line search procedures for the second points of contact as well. Since the location of second points of contact is pre-computed in the contact geometry analysis, the occurrence of two-point contact can be predicted using the look-up table in a straightforward manner. For the two-point contact scenarios encountered in curve negotiations, the online search is used for flange contacts, while the off-line search is used for tread contacts simultaneously. The on-line one-point contact search is also important for flange climb scenarios. It is demonstrated by several numerical examples that the proposed hybrid contact search algorithm can be effectively used for modeling wheel/rail contacts in the analysis of general multibody railroad vehicle systems.
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Cakdi, Sabri, Scott Cummings, and John Punwani. "Heavy Haul Coal Car Wheel Load Environment: Rolling Contact Fatigue Investigation." In 2015 Joint Rail Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/jrc2015-5640.

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Railway wheels and rails do not achieve full wear life expectancy due to the combination of wear, plastic deformation, and surface, subsurface, and deep subsurface cracks. Sixty-seven percent of wheel replacement and maintenance in North America is associated with tread damage [1]. Spalling and shelling are the two major types of wheel tread damage observed in railroad operations. Spalling and slid flat defects occur due to skidded or sliding wheels caused by, in general, unreleased brakes. Tread shelling (surface or shallow subsurface fatigue) occurs due to cyclic normal and traction loads that can generate rolling contact fatigue (RCF). Shelling comprises about half of tread damage related wheel replacement and maintenance. The annual problem size associated with wheel tread RCF is estimated to be in the tens of millions of dollars. The total cost includes maintenance, replacement, train delays and fuel consumption. To study the conditions under which RCF damage accumulates, a 36-ton axle load aluminum body coal car was instrumented with a high accuracy instrumented wheelset (IWS), an unmanned data acquisition (UDAC) system, and a GPS receiver. This railcar was sent to coal service between a coal mine and power plant, and traveled approximately 1,300 miles in the fully loaded condition on each trip. Longitudinal, lateral, and vertical wheel-rail forces were recorded continuously during four loaded trips over the same route using the same railcar and instrumentation. The first two trips were conducted with non-steering 3-piece trucks and the last two trips were conducted with passive steering M-976 compliant trucks to allow comparison of the wheel load environment and RCF accumulation between the truck types. RCF initiation predictions were made using “Shakedown Theory” [2]. Conducting two trips with each set of trucks allowed for analysis of the effects of imbalance speed conditions (cant deficiency or excess cant) at some curves on which the operating speeds varied significantly between trips.
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Cummings, Scott, Richard Reiff, John Punwani, and Todd Snyder. "Measurement of Wheel/Rail Load Environment in Relation to Rolling Contact Fatigue." In 2011 Joint Rail Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/jrc2011-56020.

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Wheel shelling is the cause of a large portion of high impact wheels. The impact loads produced by shelled wheels can have a damaging effect on track components and rolling stock components such as roller bearings. Shelling is the result of accumulated rolling contact fatigue (RCF) on the wheel tread surface. To investigate the specific conditions in which RCF occurs, wheel load environment data was collected from a car with three-piece trucks running in revenue service. This data was analyzed in order to assess the predicted wheel RCF through the use of shakedown theory. An inspection team was dispatched to several track sites to record relevant information including a visual assessment of rail RCF, rail transverse profile, rail age, and friction conditions. Track inspections were conducted at locations where RCF was predicted and at nearby locations with similar curvature where RCF was not predicted. Conclusions from this work are the following: • The curve unbalance condition, which is a combination of curvature, track superelevation, and train speed, is an important factor in RCF. • Wheel/rail coefficient of friction in curves can be a factor in RCF. • Rail profile and track condition were not found to be major factors in this analysis. • Observed rail RCF condition correlated reasonably well with predictions when considering extenuating factors such as rail age and curve unbalance conditions. • Confidence was increased in previous simulation results involving three-piece trucks due to good correlation with the results of the current work. The simulation results suggest that the use of AAR approved M-976 trucks should reduce RCF. This work was funded by the Federal Railroad Administration (FRA) and the Wheel Defect Prevention Research Consortium (WDPRC), a group that includes railroads, private car owners, and industry suppliers.
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Guan, Qinghua, Binbin Liu, and Stefano Bruni. "Effects of Non-Hertzian Contact Models on Derailment Simulation." In 2020 Joint Rail Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/jrc2020-8074.

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Abstract The derailment of trains is a complex phenomenon that requires an elaborate contact model in simulation to better understand its mechanism. The CONTACT program is a well-known reference for wheel-rail contact modeling due to its high accuracy. However, its low computational efficiency restricts its applications especially in the context of a multi-body simulation. Therefore, a high computational efficient, simplified and approximate non-Hertzian contact is preferred in derailment simulation. The aim of this research is to verify the efficiency of a recently developed non-Hertzian wheel-rail contact model in derailment simulation, which is a combination of the Kik-Piotrowski model and the KBTNH that is a fast creep force solver for non-Hertzian contacts. To assess the performance of the non-Hertzian model in derailment simulation, the derailment coefficient for steady-state and quasi-steady conditions, the wheel/rail contact forces during flange contact, and the dynamics behaviors of the wheelset prior to the derailment are compared with the state of the art contact methods representing different levels of modeling complexity, accuracy and efficiency, namely the classical approach (Hertz theory+FASTSIM algorithm) and the ‘exact’ solver CONTACT.
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Bosso, N., A. Gugliotta, and A. Soma`. "Introduction of a Wheel-Rail and Wheel-Roller Contact Model for Independent Wheels in a Multibody Code." In ASME/IEEE 2002 Joint Rail Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/rtd2002-1648.

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This paper reports the introduction of a contact model on multibody codes to simulate both wheel/rail and wheel/roller contact for independent wheel railway vehicle. The contact model has been developed both through external subroutines (used to develop the friction model and the determination of the creepages) and using standard element of the MBS code (used to define the cinematic constraints of the wheel). This model can be introduced in a general railway vehicle model with no limitations: each “contact element” so defined can be applied between two bodies of the MBS the one representing the wheel, the other the rail or the roller. It is possible to choose among several algorithms to solve the friction problem: the Fastsim code, the Polach’s method, the linearized Kalker method or a simplified analytical method with saturation. It is also possible to perform simulations using constant value for the friction coefficient and for the normal load (fast simulations) or to use a non-linear law for the friction coefficient and the actual value for the normal load on the wheel. Due to the structure of the code it is possible to change the shape of the wheels profiles during the simulations even if at the moment this features has not been introduced in the code. Finally In the paper is compared the behavior of a bogie on rail and on roller.
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Hosseinipour, Milad, Sajjad Z. Meymand, Michael J. Craft, and Mehdi Ahmadian. "Modeling of a Roller Rig for Evaluation of Wheel/Rail Contact Mechanics." In 2014 Joint Rail Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/jrc2014-3842.

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This paper provides a detailed dynamic model of the electromechanical system for a scaled roller rig that is under construction at the Railway Technology Laboratory of Virginia Tech (RTL) for accurate study of the mechanics and dynamics at wheel-rail interface in railway vehicles. Roller rigs are critical laboratory test equipment for studying rail vehicle dynamics, either as a full railcar or single component. The controlled laboratory environment will provide a successful path for obtaining data on the mechanics and dynamics of the system, including creepage and creep forces at the wheel-rail interface under various conditions. The single-wheel scaled rig under development at RTL includes a wheel that is placed on a roller with similar profile as a U.S. 136 weight rail. The test setup allows for adjusting the wheel load, the wheel angle of attack, the rail cant, and the lateral position of the wheel with respect to the rail (including flanging). The roller and the wheel are each powered independently by two AC motors that enable controlling their relative speed to a high degree of precision, i.e., 0.1 RPM, in order for precisely controlling and simulating various creep conditions that occur in practice. An essential step for the successful design and development of the test rig is modeling the motors and the roller/wheel drivelines. The model includes the electromagnetic dynamics of the AC motors, the compliances and damping of the drivelines, the inertial properties of the motors, shafts, couplers, and the rotating wheels, in a multi-domain (electrical, magnetic, and mechanical) lumped-parameter model. The model is used to determine the damped natural frequencies of the coupled system. The results of the study indicate that the compliances of the driveline mechanics is the most critical element in maintaining a prescribed speed at the driven wheel, and also controlling the relative creep between the wheel and the simulated (round) rail.
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Palese, Joseph W., Allan M. Zarembski, and Kyle Ebersole. "Stochastic Analysis of Transit Wheel Wear and Optimized Forecasting of Wheel Maintenance Requirements." In 2019 Joint Rail Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/jrc2019-1305.

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As transit vehicle wheels accrue mileage, they experience flange and tread wear based on the contact between the railhead and wheel-running surface. When wheels wear excessively, the likelihood of accidents and derailments increases. Thus, regular maintenance is performed on the wheels, until they require replacement. One common maintenance practice is truing; using a specially designed cutting machine to bring a wheel back to an acceptable profile. This process removes metal from the wheel and is often based on wheel flange thickness standards (and sometimes wheel flange angle). Wheel replacement is usually driven by rim thickness, which is continually reduced by wear and metal removed by truing. This research study used wheel wear data provided by the New York City Transit Authority (NYCTA) to analyze wheel wear trends and forecast wheel maintenance (truing based on flange thickness) and wheel life (replacement based on rim thickness). Using automatic wheel-scanning technology, NYCTA was able to collect wheel profile measurements for nearly 4,000 wheels in its fleet over a six-month period, measured weekly. The resulting wheel measurement data was analyzed using advanced stochastic techniques to determine relationships for the changes in flange thickness over time for each wheel in the fleet. Flange thickness wear rate relationships for each wheel were then used to forecast the time it would take for a wheel to reach the flange thickness maintenance threshold as defined by NYCTA standards. Furthermore, a subpopulation of wheels that exhibited very high rates of wear were classified as “bad actors” and identified for further investigation to understand the cause of accelerated wear. This allows for identification and addressing of causal factors that relate to accelerated wear, such as angle of attack and L/V ratio. NYCTA has recently started capturing such data that relates truck performance, which can be related to rate of wear.
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