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Journal articles on the topic 'Wheel / rail contact'
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1
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.
Full textAbstract:
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.
2
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.
3
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.
4
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.
5
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.
Full textAbstract:
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.
6
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.
7
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.
8
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.
Full textAbstract:
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.
9
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.
Full textAbstract:
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.
10
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.
11
Wang, Zhi Chen, Ying Song, and Ying Ming Shen. "A New Monitoring Method of Wheel/Rail Contact Forces Caused by Out-of-Round Railway Wheels." Applied Mechanics and Materials 178-181 (May 2012): 1125–30. http://dx.doi.org/10.4028/www.scientific.net/amm.178-181.1125.
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Traditional methods of wheel-rail contact forces measurement all need strain gauges on wheel sets or rails. The shortcomings of strain gauges such as zero-drift, poor anti-interference property and instability of test system can’t meat wheel/rail force test requirements in high-speed railways. A method based on PVDF piezoelectric sensing technology is presented for the test of wheel/rail contact force. Firstly, on the basis of the theory of vehicle-track coupling dynamics and by means of simulation software ADAMS/Rail, a three-dimensional train-track simulation model is established. Secondly, the modes and characteristics of wheel/rail impact vibrations due to non-roundness of railway wheels are investigated in high-speed railway operation. The relationship between the range for acceptable roundness values and vehicle speed is determined. Finally, the view that it is of important significance to establish wheel/rail force real-time monitoring system is expanded, so that abnormal conditions caused by out-of-round wheels can be detected in time, to ensure high-speed railway traffic safety. The study is very important for enhancing the stability and economy signification of rail transmission.
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Zhang, Tie, Jun Zhang, and Chuan Xi Sun. "The Profile Analysis of Wheels and Rails of Different Wear Stages for Heavy-Haul Wagons." Applied Mechanics and Materials 602-605 (August 2014): 291–94. http://dx.doi.org/10.4028/www.scientific.net/amm.602-605.291.
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A large number of wheel and rail profiles of different wear stages are tracked and measured using the wheel/rail profile admeasuring apparatus for DaTong-QinHuangdao heavy-haul line. The finite element method (FEM) models and dynamic models of the contact between wheels and rails are both established for two working conditions (i.e., straight line and curve line). In addition, the corresponding parameters and indexes are obtained through the simulation and calculation. The results show that the maximum equivalent stress for the wheel profile of type II is lower than those of wheel profiles in other stages for the straight and curve lines. Its contact stress distribution is more uniform than others. The dynamics indexes including stationarity and stability of the standard wheel profiles ( i.e. LM) are the best. The indexes are gradually reduced along with the abrasion of wheel profiles. When passing the curve, the dynamics indexes of wheel profiles in each stage are reached the evaluation standard. The abrasion rate of wheels and rails can be reduced relatively when wheels are matched with the worn rails in the stable stage.
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Li, Yang, JinJie Chen, JianXi Wang, Hu Zhao, and Long Chen. "Study on the residual stress distribution of railway rails." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 23 (May 28, 2020): 4682–94. http://dx.doi.org/10.1177/0954406220927069.
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Rolling contact fatigue damage of rails is significantly influenced by residual stresses. A three-dimensional elastic-plastic finite element model of wheel–rail contact was established in the present study, and the influence of initial stresses resulting from rail manufacturing process on the residual stress distribution of rails was analyzed. The repeated rolling passes were simulated and the stable residual stress distribution of rails was obtained. The influence of factors, such as wheel load, friction coefficient, and longitudinal creep rate, on the residual stress distribution of rails was investigated. It is found that within the limited special scale affected by the wheel–rail contact, the difference between the longitudinal residual stress with initial stresses applied and that without initial stresses applied becomes quite small once enough rolling passes have occurred (i.e., 10 rolling passes). When the initial stresses are applied, the longitudinal residual compressive stress on wheel–rail contact center of the rail is approximately 500 MPa. The residual compressive stress decreases with the increasing depth and changes from compression to tension at the depth of 6 mm beneath wheel–rail contact center of the rail. The wheel load mainly affects the residual stress distribution along the depth direction beneath rail surface. The friction coefficient mainly affects the residual stress distribution on the rail surface. The longitudinal creep rate has a great influence on the longitudinal residual stresses at the surface and along the depth of the rail.
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Ma, Xiaochuan, Ping Wang, Jingmang Xu, and Rong Chen. "Comparison of non-Hertzian modeling approaches for wheel–rail rolling contact mechanics in the switch panel of a railway turnout." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 233, no. 4 (September 20, 2018): 466–76. http://dx.doi.org/10.1177/0954409718799825.
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Due to the complicated wheel–rail contact relation of railway turnouts, it is necessary to select a reasonable rolling contact model to simulate the vehicle–turnout dynamics and wheel–rail damages. This paper mainly aims to evaluate the calculation accuracy and efficiency of different non-Hertzian modeling approaches in solving normal and tangential wheel–rail contact problems of railway turnouts. Four different non-Hertzian approaches, namely CONTACT, Kik–Piotrowski, Ayasse–Chollet, and Sichani methods are compared and analyzed. The above four models are built considering the relative motion of stock/switch rails. A wheel profile called LMA contacting with stock/switch rails (head width 35 mm) of CN60-1100-1:18 turnouts is selected as the object of analysis. The normal contact problems are evaluated by the wheel–rail contact areas, shapes, and normal contact pressures. The assessment of tangential contact problems is based on the creep curves, tangential contact stresses, and distribution of the stick/slip region. In addition, a contrast analysis is performed on the calculation efficiencies of the four approaches. It is found that the normal and tangential contact results calculated based on the Sichani method coincide well with those obtained according to CONTACT, and the calculation efficiency is about 262 times that of CONTACT. The conclusions can provide some guidance to the selection of wheel–rail rolling contact approach in the simulation of vehicle–turnout dynamics and wheel–rail damages.
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Ji, Yuanjin, Lihui Ren, Jian Wang, and Dao Gong. "Mechanism and affecting factors of Translohr tramway guide rail side wear." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, no. 21 (July 14, 2016): 3898–912. http://dx.doi.org/10.1177/0954406216660333.
Full textAbstract:
The wheel–rail contact can be found in two patterns. In the first pattern, the treads of both wheels are in contact with the two top surfaces of the ^-shaped guide rail; in the second pattern, the treads of both wheels are in contact with the two top surfaces of the ^-shaped guide rail, and the wheel edge is in contact with the guide rail web on one side. Based on these findings, an equivalent mechanical model with four unilateral springs is proposed to describe the wheel–rail contact. Additionally, a dynamic model of the Translohr tramway is established using Matlab/Simulink. The wheel–rail contact in a tramway moving along curves with different radii is calculated using simulation, and the results obtained are consistent with the observations and results of field measurements. The effects of various factors, including curve radius, tram speed, guide rail pre-pressure, and guide rod length, on the side wear of the guide rail were investigated. The results revealed that curve radius and tram speed are the critical factors affecting rail track side wear. These two factors can qualitatively determine rail track side wear, while other factors can only quantitatively affect the degree of rail track side wear.
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Andersson, C., and T. Dahlberg. "Wheel/rail impacts at a railway turnout crossing." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 212, no. 2 (March 1, 1998): 123–34. http://dx.doi.org/10.1243/0954409981530733.
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The vertical dynamics of a common Swedish railway turnout under the load of moving vehicles is investigated. The turnout is described by a linear finite element model with modal damping. The model of the turnout (a section of it) has a length of 36 sleeper spans surrounding the crossing. Rails and sleepers are modelled with uniform Rayleigh-Timoshenko beam elements. The rails are connected via railpads (linear springs) to the sleepers, which rest on an elastic foundation. The vehicles which model the dynamic behaviour of trains are discrete systems of masses, springs and dampers. They pass the turnout on the through rails at a constant speed and only vertical dynamics (including roll and pitch motions) is studied. The wheel/rail contact is modelled by use of a non-linear Hertzian spring. The train/track interaction problem is solved numerically by using an extended state space vector approach in conjunction with modal superposition for the turnout. The analyses show that the rail discontinuity at the crossing leads to an increase in the wheel/rail contact force. Both smooth and irregular transitions of the wheels from the wing rail to the crossing nose have been examined for varying speeds of the vehicle. Under perfect conditions, the wheels will change quite smoothly from rolling on the wing rail to rolling on the nose. The impact at the crossing will then be small, giving a maximum wheel/rail contact force which is only 30-50 per cent larger than the static contact force. For uneven transitions, the severity of the impact loading at the crossing depends strongly on the train speed. The increase in the contact force, as compared with the static force, is of the order of 100 per cent at 70 km/h and 200 per cent at 150 km/h.
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Корчагин, Вадим, Vadim Korchagin, Виктор Тихомиров, Viktor Tikhomirov, Александр Стриженок, Aleksandr Strizhenok, Олег Измеров, and Oleg Izmerov. "METHOD LOCOMOTIVE WHEELSLIP PREDICTION BY ANALYZING CHARACTERISTICS CONTACT WHEEL AND RAIL." Bulletin of Bryansk state technical university 2016, no. 4 (December 28, 2016): 57–65. http://dx.doi.org/10.12737/23164.
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The problems of the analytical analysis of the contact wheel and rail to meet the challenges of energy efficiency increase of the locomotive effect of the magnetic field on the contact zone. By comparing, the profiles of equations and their derivatives are defined in terms of contact with the rail wheels. Obtained geometric parameters of the wheel profile with contact rail profile.
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Six, Klaus, Tomislav Mihalj, Gerald Trummer, Christof Marte, Visakh V. Krishna, Saeed Hossein-Nia, and Sebastian Stichel. "Assessment of running gear performance in relation to rolling contact fatigue of wheels and rails based on stochastic simulations." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 4 (October 9, 2019): 405–16. http://dx.doi.org/10.1177/0954409719879600.
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In this work, the authors present a methodology for assessing running gear with respect to rolling contact fatigue of wheels and rails. This assessment is based on the wheel/rail contact data of different wheel profile wear states obtained from a wheel profile prediction methodology. The approach allows a cumulative assessment of the rolling contact fatigue of rails in different curve radii (e.g. the sum of damage over the lifetime of wheel profiles). Furthermore, the assessment of the rolling contact fatigue can be undertaken at different wear states of the wheel profiles to provide an insight on how the rolling contact fatigue of wheels and rails varies depending on the evolution of wheel wear. The presented methodology is exemplarily applied to two bogie types, the UIC-Y25 standard bogie and the so-called FR8RAIL bogie with a mechanical wheelset steering device. The presented methodology has been shown to be a useful tool for the optimisation of vehicles already in an early stage of the vehicle development process.
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Markov, D. P. "Tribology of rail bogie." Vestnik of the Railway Research Institute 77, no. 4 (August 28, 2018): 230–40. http://dx.doi.org/10.21780/2223-9731-2018-77-4-230-240.
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Railway bogie is the basic element that determines the force, kinematic, power and other parameters of the rolling stock, and its movement in the railway track has not been studied enough. Classical calculation of the kinematic and dynamic parameters of the bogie's motion with the determination of the position of its center of rotation, the instantaneous axes of rotation of wheelsets, the magnitudes and directions of all forces present a difficult problem even in quasi-static theory. The paper shows a simplified method that allows one to explain, within the limits of one article, the main kinematic and force parameters of the bogie movement (installation angles, clearance between the wheel flanges and side surfaces of the rails), wear and contact damage to the wheels and rails. Tribology of the railway bogie is an important part of transport tribology, the foundation of the theory of wheel-rail tribosystem, without which it is impossible to understand the mechanisms of catastrophic wear, derailments, contact fatigue, cohesion of wheels and rails. In the article basic questions are considered, without which it is impossible to analyze the movement of the bogie: physical foundations of wheel movement along the rail, types of relative motion of contacting bodies, tribological characteristics linking the force and kinematic parameters of the bogie. Kinematics and dynamics of a two-wheeled bogie-rail bicycle are analyzed instead of a single wheel and a wheelset, which makes it clearer and easier to explain how and what forces act on the bogie and how they affect on its position in the rail track. To calculate the motion parameters of a four-wheeled bogie, it is represented as two two-wheeled, moving each on its own rail. Connections between them are replaced by moments with respect to the point of contact between the flange of the guide wheel and the rail. This approach made it possible to give an approximate estimation of the main kinematic and force parameters of the motion of an ideal bogie (without axes skewing) in curves, to understand how the corners of the bogie installation and the gaps between the flanges of the wheels and rails vary when moving with different speeds, how wear and contact injuries arise and to give recommendations for their assessment and elimination.
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Liu, Kai, and Lin Jing. "A finite element analysis-based study on the dynamic wheel–rail contact behaviour caused by wheel polygonization." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 10 (December 4, 2019): 1285–98. http://dx.doi.org/10.1177/0954409719891549.
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In this study, an explicit finite element analysis method was adopted to investigate the wheel–rail impact response generated by wheel polygonization, using a three-dimensional wheel–rail rolling contact finite element model. In this model, the infrastructure below the rails and the stiffness and damping of the sleeper supports were considered. Then, the characteristics of the wheel–rail contact zone, the stress/strain state and the wheel–rail impact force of the polygonal wheel–rail system were presented and discussed and were compared with those of the ideally perfect wheel–rail system. A parametrical study was then carried out to examine the influences of train speed and the polygonal order of the wheel on the wheel–rail impact response. The finite element analysis results revealed that the vertical wheel–rail impact force induced by wheel polygonization is related to the wheel radial deviation; the maximum contact force, stress and strain are all elevated with the increase of the order of the polygonal wheel, which suggested that the wheel should be repaired when it is in the initial lower order polygonal state. These findings can provide some theoretical and technical support for the optimal design of the wheel–rail system and the safe operation of high-speed trains.
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Tran, Minh Thi, Kok Keng Ang, and Van Hai Luong. "Multiple-Railcar High-Speed Train Subject to Braking." International Journal of Structural Stability and Dynamics 17, no. 07 (September 2017): 1750071. http://dx.doi.org/10.1142/s0219455417500717.
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The dynamic response of a high-speed multiple-railcar train experiencing deceleration under braking condition over a straight track is investigated using the moving element method. Possible sliding of train wheels over the rails is accounted for. The train is assumed to comprise a locomotive as the leading railcar and several passenger railcars connected to each other through train couplers. Each railcar is modeled as a 15-DOF system of interconnected car body, two bogies and four wheels. The rail is modeled as an Euler–Bernoulli beam resting on a two-parameter elastic damped foundation. The train and rails are coupled through normal and tangential wheel–rail contact forces. The effects of various parameters, such as braking torque, coupler stiffness, coupler gap, wheel load, wheel–rail contact condition, initial train speed and partial failure in braking mechanism on the dynamic response of the train subject to braking are investigated. It is found that there is significant interaction between neighboring railcars when the braking torque is applied between the optimal and critical torques. The former is the torque that would result in the smallest braking distance with no occurrence of wheel sliding and the latter is the smallest torque to cause wheel sliding in all four wheels.
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Descartes, S., C. Desrayaud, and Y. Berthier. "Experimental identification and characterization of the effects of contaminants in the wheel—rail contact." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 222, no. 2 (March 1, 2008): 207–16. http://dx.doi.org/10.1243/09544097jrrt191.
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Previous results have highlighted the presence of a natural third body ranging in thickness from a few micrometres to several dozen micrometres on the rail and wheel. The third body layer, initially composed of particles stemming from the wheels and rails, flows into the contact to accommodate local sliding inside it. The work presented in this paper focuses on the identification of contaminants whose influence on the wheel—rail contact is significant. This influence can be considered as significant if it enters the contact, affects surface properties, modifies the third body layer, and possibly damages or protects the rail. The third body layer can progressively absorb and assimilate solid (ballast stone, sand) and fluid (oil) contaminants existing on rails, and thus reduce their negative consequences on rail lifetime. These phenomena are the result of the exchange of third body flows between the wheel and rail. A high-speed camera was used for this experimental study performed on a real site. The analyses of the dynamic images are coupled with tribological analyses of the surfaces by scanning electron microscopy and X-ray energy dispersive analysis.
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Zhou, Jian Hua, Yu Ji, An Chao Ren, and You Deng Zhang. "Analysis of the Generation Cause of Scale Shelling Defects on Running Surface of 60kg/m U71Mn Rail." Advanced Materials Research 291-294 (July 2011): 1062–68. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.1062.
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There were different degree scale shelling defects on running surface of 60kg/m U71Mn rail after used on the curve for a period of time, the characteristics and the generating reasons of the defects were analyzed, and the improvement measures were presented. There test results indicated that the scale shelling defects found on rail running surface were a sort of typical rolling contact fatigue damage, which caused mainly by the excessive contact stress, as a result of the wheel long-term contact with rail on the gauge corner of the rail on curve. It is effective to prevent and reduce rolling contact fatigue damage by following measures, such as improving the wheel/rail shape matching, and guaranteeing the wheel/rail interface locating on the rail tread center position, and strengthening the railway maintenance, and reasonable preventive grinding and corrective grinding for rails, and strict executing the system that rail grading use, the heat-treated rails should be used on small curve radius and heavy-load railway.
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Qian, Yao, Ping Wang, Yibin Liu, Tianci Gao, Jingmang Xu, and Yuan Wang. "Using the geometric wheel-rail contact algorithms for fault detection in turnout areas based on the variable section characteristics of rails." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 5 (May 31, 2019): 550–63. http://dx.doi.org/10.1177/0954409719848602.
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This paper presents a geometric wheel–rail contact algorithm suitable for fault detection in a railway turnout. It employs a dynamic profile sampling method based on the characteristics of the variable section rails in the turnout regions. This algorithm provides a fast and accurate method to identify the wheel–rail contact points in turnouts under different degrees of lateral shift and yaw angles. This method determines the contact point based on the minimum distance and can be applied quickly through the use of a moving window to scale the potential contact boundary within the rail width. The wheel–rail contact points and the geometric contact parameters in the internal rail that matched with the LMa and 60 N were virtually identical in both methods, which verifies the accuracy of the dynamic profile sampling model. A comparison of the different wheel–rail contact points and geometric parameters under different wheelset yaw angles in turnouts using the trace line and dynamic profile sampling methods shows that a trace method based on the assumption of equal rail sections is not applicable to turnouts, thus demonstrating the necessity of calculating the wheel–rail contact geometry in turnouts using the dynamic profile sampling method, which takes the characteristics of the variable sections into account.
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Bureika, Gintautas, and Šarūnas Mikaliūnas. "PECULIARITIES OF TRACTION FORCES IN WHEEL/RAIL CONTACT AREA." TRANSPORT 17, no. 1 (February 28, 2002): 8–14. http://dx.doi.org/10.3846/16483480.2002.10414004.
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Tractive force and train movement stability dependence on division of forces involved in wheel/rail contact area are the main subjects of this article. The influence of wheel/rail contact properties in the vehicle dynamics and adhesion fields is investigated. Current tendency all over the world is to reduce the conicity of wheels with the aim of increasing the speed of trains. Wave-length of moving wheel-set in track for worn wheel-set tyre is twice less than for new wheel running profile.
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Yu, Miao, Wei-dong Wang, Jin-zhao Liu, and Shan-chao Sun. "The transient response of high-speed wheel/rail rolling contact on “roaring rails” corrugation." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 233, no. 10 (February 2, 2019): 1068–80. http://dx.doi.org/10.1177/0954409719825682.
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A high-speed wheel/rail finite element model is developed to focus on the non-steady-state rolling contact. The wheel/rail contact is solved based on the surface-to-surface contact algorithm, and the explicit finite element method is used to simulate the dynamic high-speed wheel/rail rolling contact. Considering the track–vehicle coupling system dynamics and the wheel/rail geometric nonlinearities, the wheel/rail contact on the short wave rail corrugation under the high-frequency vibration and the influence of train passing frequency on the track–vehicle system dynamics are studied. The explicit finite element method can be used to simulate the non-steady-state rolling contact process of the high-speed wheel/rail. After the initial load condition, the wheel/rail contact state tends to be stable in a short period of time. The short wave corrugation causes the high-frequency vibration of the track–vehicle system; the slightly advanced phase of the wheel/rail contact force promotes the development of rail corrugation in the rolling direction. When the train passing frequency is close to the rail pinned–pinned frequency, the pinned–pinned resonance occurs. The overall vibration near the fastening is relatively large and accelerates the damage of components. The longitudinal force is clearly affected by the traction torque with a periodic wheel/rail stick-slip vibration. The pinned–pinned resonance will promote the sliding wear at the wave trough near the fastening and it will become severe with the increase of the traction.
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Xiao, Xiang, and Wei-Xin Ren. "A Versatile 3D Vehicle-Track-Bridge Element for Dynamic Analysis of the Railway Bridges under Moving Train Loads." International Journal of Structural Stability and Dynamics 19, no. 04 (April 2019): 1950050. http://dx.doi.org/10.1142/s0219455419500500.
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There has been a growing interest to carry out the vehicle–track–bridge (VTB) dynamic interaction analysis using 2D or 3D finite elements based on simplified wheel–rail relationships. The simplified or elastic wheel–rail contact relationships, however, cannot consider the lateral contact forces and geometric shapes of the wheel and rails, and even the occasional jump of wheels from the rails. This does not guarantee a reliable analysis for the safety running of trains over bridges. To consider the wheel–rail constraint and contact forces, this paper proposes a versatile 3D VTB element, consisting of a vehicle, eight rail beam elements, four bridge beam elements, and continuous springs as well as the dampers between the rail and bridge girder. With the 3D VTB element matrices formulated, a procedure for assembling the interaction matrices of the 3D VTB element is presented based on the virtual work principle. The global equations of motion of the VTB interaction system are established accordingly, which can be solved by time integration methods to obtain the dynamic responses of the vehicle, track and bridge, as well as the stability and safety indices of the moving train. Finally, an illustrative example is used to verify the proposed the versatile 3D VTB element for the dynamic interactive analysis of railway bridges under moving train loads.
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Kapitsa, Mikhail, Evgen Mikhailov, Sergii Kliuiev, Stanislav Semenov, and Maksim Kovtanets. "Study of rail vehicles movement characteristics improvement in curves using fuzzy logic mechatronic systems." MATEC Web of Conferences 294 (2019): 03019. http://dx.doi.org/10.1051/matecconf/201929403019.
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The article deals with the effectiveness of reducing the level of force interaction of the rail vehicle wheels with rails in curved sections of the track through the use of mechatronic position control systems for wheel pairs in the rail gauge in the horizontal plane. The approaches to the creation of such a mechatronic system operating on the principles of fuzzy logic are described. To determine the angles of attack of wheels on the rails, it was proposed to use the acoustic emission indicators of the contact of the wheel with the rail. To determine the direction of curvature of the rail track, it is advisable to use data from navigation systems. The study of the dynamics of the rail vehicle during the passage of a curved section of the track in real time was carried out using the Matlab/Simulink software package. The proposed mechatronic control system for the position of the wheel sets in the horizontal plane allows to ensure their optimal installation under various driving conditions in the rail gauge. This makes it possible to minimize the angles of attack of the wheels and reduce the forces of the horizontal interaction of the wheels with the rails.
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Hou, Maorui, Bingzhi Chen, and Di Cheng. "Study on the Evolution of Wheel Wear and Its Impact on Vehicle Dynamics of High-Speed Trains." Coatings 12, no. 9 (September 14, 2022): 1333. http://dx.doi.org/10.3390/coatings12091333.
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Wheel wear is one of the most critical factors affecting the vehicle performances and maintenance costs of railway vehicles. However, previous research has to ignore the initial wheel-rail profiles for the evolution of wheel wear. Therefore, this work investigates the relationship between the evolution of wheel wear corresponding to different initial wheel-rail profiles and vehicle dynamics, wheel-rail deterioration. Firstly, the evolution of wheel wear during a long service period is measured from two high-speed railway trains running on two different lines. Contact geometry, e.g., equivalent conicity and contact pair distribution, are extracted. After that, the influence of wheel wear on the vehicle dynamic performance is studied using a multi-body dynamic software. The calculated contact parameters, e.g., pressure, shear traction, and creepage, are used to analyze the distribution of rolling contact fatigue. Based on the experimental and simulation results, the initial wheel and rail profiles significantly affects the wheel wear pattern, the thin rim wheel has uniform wear, and other wheels occurs hollow wear. The hollow wear can lead to gradual deterioration of vehicle dynamics, which conversely aggravates the wheel reprofiling.
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Wei, Kai, Rui Ying Chen, and Yu De Xu. "Rail Profile Wear on Curve and its Effect on Wheel-Rail Contact Geometry." Advanced Materials Research 779-780 (September 2013): 655–59. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.655.
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The paper has carried out continued tests on a curve of a heavy haul railway in China for its rail profiles. Based on the data, the paper has counted the development of the rail profile wear, and then analyses the influence of wheel-rail contact geometry on the rail profile wear. The results show that the wear of high rails develops around the rail corners, while the one of low rails around the rail top. The development of the rail wear speeds up after the transport mass passes 210MGT. The wheel-rail contact geometry deteriorates when the transport mass grows up to 60MGT and lower than 210MGT.
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Babici, Laura Mariana, Andrei Tudor, and Jordi Romeu Garbi. "Acoustic emission at the wheel-rail contact with micro-slip and stick-slip." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 6 (February 1, 2023): 1477–84. http://dx.doi.org/10.3397/in_2022_0205.
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The paper aims to analyse the occurrence of acoustic emission at the wheel-rail contact during micro-slip. The experimental model allows the contact pressure variation (MPa..GPa) and the sliding speed (0.01 to 0.5 mm/s) specific to the wheel-rail contact. It is determined experimentally and theoretically the appearance of the stick-slip phenomenon at the Hertzian contact of cylinder type (fixed-wheel specimen) - plane (mobile with very low speed - rail specimen). The experimental stand simultaneously measures the normal force, the friction force and the acoustic emission at different contact pressures, sliding speeds and rigidities of the wheel specimen fixing system. The specimens are made of UIC standard materials used in the driving wheels and rails. The stick-slip phenomenon occurs at low micro-slip speeds and normal bending stiffness. Experimentally, it is found that the jumps specific to the stick-slip phenomenon( friction coefficient-COF) are accompanied by the acoustic emission (AE) at the cylinder-plane interface. The energy emitted by AE (WAE) is correlated with the energy consumed by friction during the stick-slip period (WCOF). The theoretical model regarding the stick-slip phenomenon of the Hertzian contact with slip specific to the experimental stand allows the analysis of the stability of the stick-slip movement.
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Sebeşan, Ioan, and Valeriu Ştefan. "The Influence of the Suspension on the Phenomena of Wheel-Rail Contact." Applied Mechanics and Materials 809-810 (November 2015): 1061–66. http://dx.doi.org/10.4028/www.scientific.net/amm.809-810.1061.
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Efficient use of adhesion between wheels and rails involves a good knowledge of this phenomenon, in order to equip the vehicle with adequate facilities and systems that protect the vehicle and the rail. The loading of the vehicle's axle with dynamic loads in vertical and horizontal planes, are to be developed in the area of contact, both normal stress and shear distributed stress, their sum giving the friction force and the moment of pivoting friction (spin). This makes the wheel-rail contact problems take the two aspects of the study, namely the problem of normal and tangential contact issue. The normal contact problem involves regular geometric shape bodies, determining the size of the resulting contact surface, the distribution of the normal contact pressures and the relationship between the proximity of the bodies and the normal contact force. Solving the problem of the tangential wheel-rail contact is about to establish the correlation between the creepage, normal contact forces and friction forces, and also the ratio between the adherent contact surface and the nominal contact surface where the creepage ocurs.
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Pau, M. "Ultrasonic waves for effective assessment of wheel-rail contact anomalies." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 219, no. 2 (March 1, 2005): 79–90. http://dx.doi.org/10.1243/095440905x8808.
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Ultrasonic waves are routinely used in the railway industry to supply information about integrity of wheels, rails, and axles for both quality control assessment (during the production process) and ‘in situ’ when the rolling stock has to be periodically checked for maintenance purposes. Nevertheless, recently the authors proposed a different application of this technique which, although employing the same kind of equipment as a standard NDE control, is able to investigate the main features of the wheel-rail contact interface such as nominal contact area, real contact area, and contact pressure distribution. On the grounds of the promising results obtained in the previous tests, this study proposes a further practical approach to common problems of wheel-rail contact that possibly affect the regular development of railway operations. To this end, a number of wheel-rail systems were altered by artificially producing several kind of defects on their surfaces and thus obtained couplings were then analysed by the ultrasonic method in order to assess the capability of the technique to faithfully reproduce the modification introduced in the contact patch. The results of the experimental tests allow us to state that the ultrasonic analysis of wheel-rail contact interfaces can be effectively employed to detect any sort of irregularities potentially present due to normal operations, and foresees a future application of the method as a tool to monitor critical points of a railway line in order to ensure significant improvements in safety conditions.
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An, Boyang, Jing Wen, Panjie Wang, Ping Wang, Rong Chen, and 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 (April 2, 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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Aceituno, Javier F., Pu Wang, Liang Wang, and Ahmed A. Shabana. "Influence of rail flexibility in a wheel/rail wear prediction model." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 231, no. 1 (August 5, 2016): 57–74. http://dx.doi.org/10.1177/0954409715618426.
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The aim of this paper is to study the influence of rail flexibility when a wheel/rail wear prediction model that computes the material loss based on an energy approach is used. The wheel/rail wear model used in this investigation is a simplified combined wear hypothesis that is based on the frictional energy loss in the contact patch. In order to account for wear and its distribution in a profiled wheel surface, the contact forces, creepages and location of the wheel/rail contact points are first calculated using a fully nonlinear multibody system (MBS) and three-dimensional contact formulations that account for the rail flexibility. The contact forces, creepages and contact point locations are defined as nonlinear functions of the rail deformations. These nonlinear expressions are used in the wear calculations. The wear distribution is considered to be proportional to the normal force in the contact area. Numerical simulations are first performed in order to compare between the results obtained using the simplified wheel/rail wear model and the results obtained using Archard’s wear model with a focus on sliding when the track is modeled as a rigid body. This simplified wear model is then used in the simulation of the MBS vehicle model in the case of a flexible body track, in which the rails are modeled using the finite element floating frame of reference approach and modal reduction techniques. The effect of the rail deformation on the wear results are examined by comparing these results with those obtained using the rigid-body track model.
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Marshall, M. B., R. Lewis, R. S. Dwyer-Joyce, U. Olofsson, and S. Björklund. "Experimental Characterization of Wheel-Rail Contact Patch Evolution." Journal of Tribology 128, no. 3 (March 21, 2006): 493–504. http://dx.doi.org/10.1115/1.2197523.
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The contact area and pressure distribution in a wheel/rail contact is essential information required in any fatigue or wear calculations to determine design life, re-grinding, and maintenance schedules. As wheel or rail wear or surface damage takes place the contact patch size and shape will change. This leads to a redistribution of the contact stresses. The aim of this work was to use ultrasound to nondestructively quantify the stress distribution in new, worn, and damaged wheel-rail contacts. The response of a wheel/rail interface to an ultrasonic wave can be modeled as a spring. If the contact pressure is high the interface is very stiff, with few air gaps, and allows the transmission of an ultrasonic sound wave. If the pressure is low, interfacial stiffness is lower and almost all the ultrasound is reflected. A quasistatic spring model was used to determine maps of contact stiffness from wheel/rail ultrasonic reflection data. Pressure was then determined using a parallel calibration experiment. Three different contacts were investigated; those resulting from unused, worn, and sand damaged wheel and rail specimens. Measured contact pressure distributions are compared to those determined using elastic analytical and numerical elastic-plastic solutions. Unused as-machined contact surfaces had similar contact areas to predicted elastic Hertzian solutions. However, within the contact patch, the numerical models better reproduced the stress distribution, as they incorporated real surface roughness effects. The worn surfaces were smoother and more conformal, resulting in a larger contact patch and lower contact stress. Sand damaged surfaces were extremely rough and resulted in highly fragmented contact regions and high local contact stress.
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Chen, Rui Ying, Kai Wei, and Yu De Xu. "Simulation Analysis on Wheel and Groove Rail Contact Position." Advanced Materials Research 779-780 (September 2013): 607–10. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.607.
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A vehicle-rail dynamic model is established and the calculated results are verified with trace method. And under the conditions of a same curve section, simulations are made on the contact position of groove rail and standard rail. Variation of contact points and contact area are analyzed. Furthermore, comparisons are made on the two rails with different lateral displacements.
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Wang, Pu, Liang Gao, and Bo Wen Hou. "Influence of Rail Cant on Wheel-Rail Contact Relationship and Dynamic Performance in Curves for Heavy Haul Railway." Applied Mechanics and Materials 365-366 (August 2013): 381–87. http://dx.doi.org/10.4028/www.scientific.net/amm.365-366.381.
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Rail cant is one of the most important track geometry parameters, which can change the wheel-rail contact relationship and then influence the dynamic interaction. Static contact geometry parameters for 75kg/m rail in contact with LM wheel tread under different rail cants are analyzed on the basis of the wheel-rail spatial contact geometry algorithm. A train (multi-vehicle)-track coupling dynamic model is established with the help of the software Universal Mechanism (UM), and dynamic performances of train-track system in curves are compared under different rail cants. The results indicate that: (1) flange contact is less likely to occur under 1/20 rail cant, which will reduce uneven wear of wheel/rail tread. (2) In the single-point contact range, when the rail cant increases from 1/40 to 1/20, the corresponding rolling radius difference, contact angle parameter, equivalent conicity and equivalent contact angle parameter all increase, which means the self-centring capacity of wheelset is enhanced and the wheel-rail relationship is improved. (3) When the train passes curves, the increase of rail cant from 1/40 to 1/20 can reduce the wheel-rail dynamic interaction and wear. Besides, the wheel-rail contact area may become bigger, which is conductive to reducing contact stress and contact fatigue failures. The results can provide reference for the design of rail cant of heavy haul railway.
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Vernersson, T., and R. Lundén. "Temperatures at railway tread braking. Part 3: wheel and block temperatures and the influence of rail chill." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 221, no. 4 (July 1, 2007): 443–54. http://dx.doi.org/10.1243/09544097jrrt91.
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Tread braking generates high temperatures in railway wheels and brake blocks as the kinetic energy of the running train is transformed into heat. The temperatures induced in the components are here analysed with particular focus on the cooling influence from the rolling contact between the hot wheel and a cold rail. Controlled brake rig tests are reported, where the rolling contact is studied using a so-called rail-wheel in contact with the braked wheel, along with results from field tests. The data from these experimental studies are used for calibration of a simulation tool for calculation of wheel and block temperatures. The calibrated model analyses heat partitioning between block, wheel and rail and finds the resulting temperatures at braking. The rail chill is found to have a considerable influence on the wheel temperatures for long drag braking cycles. A successful calibration of the model using data from field tests is also reported.
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Chen, Yung-Chuan, and Jao-Hwa Kuang. "Partial Slip Rolling Wheel-Rail Contact With a Slant Rail Crack." Journal of Tribology 126, no. 3 (June 28, 2004): 450–58. http://dx.doi.org/10.1115/1.1759339.
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This paper investigates the tip characteristics of an oblique crack in the wheel-rail contact problem. The wheel-rail normal contact pressure and interfacial shear stress distributions, and the stress intensity factors (SIF), are studied for oblique cracks of different inclinations, and the variations in both contact stress distributions near the crack edge are simulated under normal and traction loads, respectively. Contact elements are employed to model the interactions between the wheel-rail contact surfaces and the crack surfaces, respectively. The effects of crack orientation, crack length, and contact distance on the contact stress distributions and stress intensity factors, KI and KII, are investigated. The results indicate that a wheel-rail traction force reduces KII significantly as the contact point travels over the crack edge. Furthermore, fluctuations in KI and KII are very significant with regard to early squat propagation of cracks. The results also demonstrate that applying Carter’s contact model or the full slip contact model to the same wheel-rail contact crack problem yields significantly different stress intensity factor values.
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Fajdiga, Gorazd, Matjaž Šraml, and Janez Kramar. "Modelling of Rolling Contact Fatigue of Rails." Key Engineering Materials 324-325 (November 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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Kalker, J. J. "Wheel-rail rolling contact theory." Wear 144, no. 1-2 (April 1991): 243–61. http://dx.doi.org/10.1016/0043-1648(91)90018-p.
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Mao, Xin, and Gang Shen. "A design method for rail profiles based on the geometric characteristics of wheel–rail contact." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 5 (July 10, 2017): 1255–65. http://dx.doi.org/10.1177/0954409717720346.
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Designing a proper rail profile carries more significance than designing a wheel profile because of the amount of work and cost involved in the maintenance of rails. A better rail profile will not only help to ensure achieving the desired dynamic performance of rail vehicles but it also extends the service life of rails. This paper presents a unique design method for the design of rail profiles based on the given geometric contact characteristics. The proposed method utilizes a given wheel profile and two typical functions respectively to set the main design targets. The first function is the rolling radii difference and the second one is the contact angle difference. Wheel–rail contact distribution is chosen as the secondary target to prevent stress concentration and the associated fatigue failure. With certain assumptions, the solution process becomes a reverse designed one, which can be solved by using proper discrete numerical methods. Two examples of rail profile designs have been discussed in detail for rigid and independent wheelsets.
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Choi, Jung-Youl, Sang-Won Yun, Jee-Seung Chung, and Sun-Hee Kim. "Comparative Study of Wheel–Rail Contact Impact Force for Jointed Rail and Continuous Welded Rail on Light-Rail Transit." Applied Sciences 10, no. 7 (March 27, 2020): 2299. http://dx.doi.org/10.3390/app10072299.
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In this study, the measured track impact factor induced by the wheel–rail contact impact force of each test section (two continuous welded rails on slab tracks and rail joint on a ballasted track) was compared with the design track impact factor under service conditions of a curved light-rail transit system. The measured track impact factor (TIF) was estimated from the measured dynamic wheel load and vertical rail displacement at each test section. In the case of the rail joint section, the rail joint was found to directly affect the track impact factor. Moreover, the dynamic wheel load fluctuation and vertical rail displacement were found to be significantly greater than those of the continuous welded rails (CWRs) on slab tracks. In addition, vertical rail displacements were measured by field measurement and finite element analysis (FEA) was conducted to simulate dynamic wheel load on the jointed rail. Using the field measurements, the rate of dynamic wheel load fluctuation and the TIF were calculated for the CWR and rail joint sections. Subsequently, the calculated TIF values were analytically validated through a comparison with the measured vertical rail displacement, the results of FEA, and the designed TIF for rail joints and CWRs. Finally, the TIF measured by field measurement was compared with the result predicted by FEA. The difference between the results of field measurements and FEA for vertical rail displacement was within approximately 4%.
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Suparno, Joko, Dimas Ardiansyah Halim, Junaidi, Ady Setiawan, Marwan Effendy, and J. Jamari. "Graphite as Dry Lubricant to Reduce Rail Wheels Wear Level." Materials Science Forum 961 (July 2019): 126–33. http://dx.doi.org/10.4028/www.scientific.net/msf.961.126.
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Wear occurs in rail wheels due to varying surface contact between wheel and railway. Many materials are used to minimize the wear effect of friction, one of which is graphite. Graphite has been known having dry lubricating ability. To find out the effect of graphite lubrication on wear level of wheel and railway, an experiment-based research is important to conduct. This research started with designing the construction of disc-on-disc wear testing instrument, wheel specimen using EMS45 material and railway specimen using VCL140 material. Dry lubricant used was graphite bar polished onto wheel specimen surface. The result of research showed that graphite could adhere to wheel surface and penetrate into the fissures of contact between wheel and railway. Varying graphite polishing conducted once in 5 minutes and 10 minutes resulted in different volume of graphite filling in the fissures of wheel specimen surface. The more the graphite volume polished onto wheel specimen surface, the less is the material loss due to surface contact. Graphite’s ability of filling in this contact area fissure when administered in appropriate volume would enable graphite to be a good dry lubricant. If this graphite polishing technique is applied to rail wheels, it would be beneficial, as it can lengthen the wheel life.
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Gu, Shao Jie, Xin Wen Yang, and Song Liang Lian. "An Analysis of 3-D Wheel-Rail Contact Stress under Heavy Axle Load Using Non-Linear Finite Element Method." Applied Mechanics and Materials 638-640 (September 2014): 1128–34. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.1128.
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Wheel-rail contact stress is foundation of the relationship between wheel and rail, and also an important basis for investigating further wear, surface damage and other problems of wheel and rail system. A three dimension elastic-plastic wheel/rail contact model is established using non-linear finite element method. The changes of wheel/rail normal contact stress, Mises stress and elastic-plastic deformations are analyzed under different conditions in heavy haul railway. A method is provided for a foundation of the future study of wheel-rail contact wear, fatigue and cracks germination and development in this paper.
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Wu, Feng Qi, Jin Zhang, and Wen Qing Yao. "Crane Wheel-Rail Contact Stresses Research Based on Experimental Test and Finite Element Analysis." Applied Mechanics and Materials 496-500 (January 2014): 662–65. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.662.
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The wheel-rail contact is a boundary condition highly nonlinear complex problem, which need to accurately track the wheel-rail movement and the interaction contact stress between wheel-rail before and after the occurrence of wheel-rail contact, nonlinear contact stress of wheel-rail is analyzed through the contrast of finite element analysis and the actual detection, the experimental and theoretical calculation results show the compliance of the finite element model of wheel-rail, at the same time also point out some differences of theoretical calculation and actual manufacturing, which establish the theoretical and experimental foundation for the advanced research movement friction etc..
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Kumar, S., and S. P. Singh. "Threshold Stress Criterion in New Wheel/Rail Interaction for Limiting Rail Damage Under Heavy Axle Loads." Journal of Engineering for Industry 114, no. 3 (August 1, 1992): 284–88. http://dx.doi.org/10.1115/1.2899793.
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This paper presents a qualitative discussion of the effects of increasing new (initial) wheel-rail contact stresses on the degree of damage to the rail due to heavy axle loads. The importance and need of heavy axle loads and its relationship to rail damage as a result of the increasing wheel-rail contact stresses is discussed. Various mechanisms of energy absorption/losses due to free rolling and modes of rail damage are presented. These modes include surface and internal damage due to wear, contact shear, plasticity, fatigue, shelling, crack formation, etc. The concept of threshold stress observed in free rolling friction much earlier by Drutowski is discussed and analyzed. It is believed by the authors that the threshold stress is s material property. This concept of threshold stress, based on sharply increased rates of wear in free rolling contact, is then presented and analyzed. Considerations of increased plasticity-region development, due to increasing contact stresses and their relationship to increased rates of wear seen in experiments, is utilized to determine an upper bound of contact stresses for new wheel and rail under heavy axle load conditions. It is indicated that new wheel-rail profiles, which will achieve contact stresses below the threshold stress, will enable the U.S. railroads to carry heavy axle loads without serious future damage to the rails. It is concluded that a satisfactory solution for maintaining rail integrity under heavy axle loads is possible with proper design accompanied with laboratory experimentation for the new steels as they may be used in the rails.
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Vickerstaff, Andy, Adam Bevan, and Pelin Boyacioglu. "Predictive wheel–rail management in London Underground: Validation and verification." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 4 (October 10, 2019): 393–404. http://dx.doi.org/10.1177/0954409719878616.
Full textAbstract:
London Underground is facing the challenge of increasing timetables against spending cuts across renewals and maintenance in all assets. In order to meet this challenge, it is reviewing all maintenance practices to make sure that they are appropriate for the current asset conditions. Management of the wheel–rail interface is critical to maximising the life of wheels and rails through preventative maintenance regimes that ensure all activities offer value for money and safe operation. Detailed monitoring of the asset condition using novel non-destructive techniques has allowed the identification of the problems which currently occur at the wheel–rail interface on the London Underground network. These problems are discussed in this paper along with some of the solutions proposed to manage them. Site observations from a range of rail rolling contact fatigue monitoring sites have also been compared to the outputs from vehicle dynamic simulations. These outputs were post-processed using a circle plotting technique, which illustrates the location, direction and severity of the forces, and the Whole Life Rail Model to predict the susceptibility to rail damage for two rail steel grades. The outputs from these comparisons have helped to illustrate the wheel–rail contact conditions and forces which are driving the observed damage and potential future enhancements to improve the accuracy of the models for predicting the observed rolling contact fatigue damage.
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Xue, Fuchun. "Investigation of rolling wheel–rail contact using an elaborate numerical simulation." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 10 (November 6, 2019): 1198–209. http://dx.doi.org/10.1177/0954409719886171.
Full textAbstract:
In this paper, a non-linear model is developed for analyzing rolling wheel–rail contact in a wheel–track–infrastructure system. Because of the random irregularity across the surface of the rail, the process of the wheel accelerating from rest and rolling forward at its expected speed can be simulated and verified. The dynamic characteristics of the rolling wheel–rail contact at the expected speed are also carefully investigated. The results showed that the top of the rail consists of spatially curved planes due to the deformation induced by the rolling wheel. In addition to the adhesion and slipping zones, there was also a disengaging zone existing within the contact area. The random irregularity throughout the top of the rail significantly reduced the area of contact between the wheel and the rail. By comparing the Hertz contact theory with a smooth rail top, significant differences were observed in the vertical contact stress distribution mode throughout the contact area for the real wheel–rail rolling contact, with a sharp increase in the absolute values of contact pressure. The stress distribution in the contact area was highly non-uniform, and a severe local concentration of dynamic stress was observed.