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Journal articles on the topic '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.
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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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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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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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Seo, Jung Won, Hyun Kyu Jun, Seok Jin Kwon, and Dong Hyeong Lee. "Rolling Contact Fatigue and Wear Behavior of Rail Steel under Dry Rolling-Sliding Contact Condition." Advanced Materials Research 891-892 (March 2014): 1545–50. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.1545.
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Rolling contact fatigue and wear of rails are inevitable problems for railway system due to wheel and rail contact. Increased rail wear and increased fatigue damage such as shelling, head check, etc. require more frequent rail exchanges and more maintenance cost. The fatigue crack growth and wear forming on the contact surface are affected by a variety of parameters, such as vertical and traction load, friction coefficient on the surface. Also, wear and crack growth are not independent, but interact on each other. Surface cracks are removed by wear, which can be beneficial for rail, however too much wear shortens the life of rail. Therfore, it is important to understand contact fatigue and wear mechanism in rail steels according to a variety of parameters. In this study, we have investigated fatigue and wear characteriscs of rail steel using twin disc testing. Also the comparative wear behavior of KS60 and UIC 60 rail steel under dry rolling-sliding contact was performed.
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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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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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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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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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Seo, Jung Won, Seok Jin Kwon, Hyun Kyu Jun, and Dong Hyung Lee. "Microstructure Features and Contact Fatigue Crack Growth on Rail." Materials Science Forum 654-656 (June 2010): 2491–94. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.2491.
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Rolling Contact Fatigue (RCF) damage on the surface of rails such a head check, squats is a growing problem. Since rail fractures can cause derailment with loss of life and property, the understanding of rail fracture mechanism is important for reducing damages on the rail surface. In this study, we have investigated RCF damage, fatigue growth and fracture surface morphology on the surface of broken rail using failure analysis and finite element (FE) analysis. The investigation indicates that the crack grows at about 20° to the depth of 8mm from the surface and branches into two cracks. One crack propagates downward at about 47°, the other propagates upward. Since the crack growth rate of the downward crack was faster than that of upward crack, rail eventually was broken. Since the downward branches lead to fracture of the rail, they are more dangerous to the integrity of rails. It has been observed that White Etching Layer (WEL) occurs within the surface of broken rail. It was found that the fatigue crack initiation and propagation was accelerated by WEL.
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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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Sasaki, Toshihiko, Osama Yaguchi, and Yuichi Kobayashi. "A Study on Area Detector Type Diffraction Stress Measurement and its Application to Shelling Problem in Railway Tracks." Materials Science Forum 638-642 (January 2010): 2458–63. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.2458.
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In order to study on the effects of grinding of rail head on rolling contact fatigue of rails, residual stress measurements were conducted for rails processed under different grinding conditions. In this study, residual stresses in rails used for a service line were measured with the method of X-ray stress measurement. The triaxial stress analysis was conducted using a new method for an area detector type X-ray stress analysis proposed by the authors. Four grinding conditions were used to rail specimens. The distributions of residual stresses in the surface layer of the rail head were obtained. It was found that the tensile residual stresses were generated at the field-side of the ground rai1, and that the triaxial stress state was formed in the surface of the rail head widely.
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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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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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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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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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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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Kossov, V. S., A. V. Savin, and O. G. Krasnov. "On the Issue of Determining Relative Rail Rolling Contact Fatigue Damageability." World of Transport and Transportation 19, no. 1 (September 8, 2021): 6–17. http://dx.doi.org/10.30932/1992-3252-2021-19-1-06-17.
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Adoption of heavy haul traffic on many railroads, comprising Russian railways, has highlighted the relevance of assessing the effect of increased axial loads on the contact fatigue life of rails.The article describes a set of theoretical studies carried out to create a scientifically substantiated method for predicting the contact fatigue life of rails depending on the values of axial loads. The stress-strain state of the contact area has been determined using the finite element model of wheel rolling on a rail. It has been found that the wheel-rail rolling contact area undergoes complex multiaxial loading with the simultaneous action of normal and shear strains. Based on the analysis of models describing multiaxial fatigue damage, the Brown–Miller model was chosen, which considers the simultaneous action of normal strains at the contact area and of maximum shear strains, which most fully describes the stress-strain state of the wheel-rail rolling contact area. To apply the Brown–Miller model, fatigue stress-strain curves for rail steel have been identified. Based on the analysis of methods for determining the parameters of stress-strain curves carried out by V. A. Troschenko, a modified Roessle– Fatemi hardness method has been applied. Based on the experimentally determined values of hardness on the rolling surface, the parameters of the curves of elastic and plastic fatigue have been revealed by calculation and experiment. To establish the damaging effect of the load from wheel rolling on a rail, the concept of relative damage per rolling cycle had been assumed which is the value inverse to the number of cycles preceding formation of a contact-fatigue crack at a given value of the axial load.Calculations of the relative damage rate of the rolling surface of rails caused by contact fatigue defects were carried out with the Fatigue software package considering mean values of the indicators of the degree of fatigue strength and plasticity of rail steel and the calculated stresses in the wheel-rail contact area, as well as the plasticity correction using Neuber method. The polynomial dependence of relative damageability of the rolling surface of rails is obtained. The established functional dependence of relative damageability of the rolling surface of rails on the values of vertical forces can be used as the basis for the developed methodology for predicting the contact fatigue life of rails.
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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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Xu, Jingmang, Ping Wang, Jian Wang, Boyang An, and Rong Chen. "Numerical analysis of the effect of track parameters on the wear of turnout rails in high-speed railways." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 3 (December 22, 2016): 709–21. http://dx.doi.org/10.1177/0954409716685188.
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In this study, a numerical procedure is developed to predict the wear of turnout rails, and the effect of track parameters is investigated. The procedure includes simulation of the dynamic interaction between the train and the turnout, the rolling contact analysis, and the wear model. The dynamic interaction is simulated with the validated commercial software Simpack that uses a space-dependent model of a railway turnout. To reproduce the actual operating conditions of a railway turnout, stochastic variations in the input parameters are considered in the simulation of the dynamic interaction. The rolling contact is analyzed with the semi-Hertzian method and improved FASTSIM algorithm, which enable the contact model to deal with situations of multipoint contact and nonelliptic contact. Based on the Archard’s wear law, the wear model requires the calculation of normal/tangential stresses and a relative slide on the contact patches. The numerical procedure is performed for the selected sections of the vehicle, which runs through the railway turnout in the diverging route. By using the numerical procedure, the effect of track parameters (track gage, rail inclination, and friction coefficient) on the wear of turnout rails is analyzed. The results show that the wear of the front wheelset is more serious than the wear of the rear wheelset for a single vehicle. The degree of wear of switch rails is more severe than that of the stock rails and the difference is more obvious for the front wheelset of the switch rails. The wear of switch rails is mainly concentrated on the rail gage corner, while the wear of stock rails is mainly concentrated on the rail crown. For the analysed CN60-1100-1:18 turnout and the high-speed vehicle CRH2 in China, the rail wear rate could be slowed down by increasing the track gage and decreasing the rail inclination. Alternatively, the rail wear rate could be slowed by decreasing the friction coefficient; however, the variation of wear depth is quite small for friction coefficients that are larger than 0.3.
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Moreau, A. "Le contact roue-rail." Revue de Métallurgie 88, no. 12 (December 1991): 1211–22. http://dx.doi.org/10.1051/metal/199188121211.
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Kuznetsova, N. V., and E. A. Sidorova. "Features of the influence of intermediate rail fastenings on the operational durability of rails." VNIIZHT Scientific Journal 80, no. 4 (September 1, 2021): 201–8. http://dx.doi.org/10.21780/2223-9731-2021-80-4-201-208.
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Heat-strengthened rails of the R65 type are the main type of rails used on the railway network of Russian Railways. Reducing the number of cropped and acutely defective rails is possible due to the rational use of the design features of intermediate rail fasteners and their current content.The article presents study results of the stiffness influence of intermediate fasteners on the operational durability of rails. The general statistics of the use of various types of intermediate rail fastenings on the network of Russian railways is considered. The main results of previously published studies on the effect of the stiffness of intermediate rail fasteners on the accumulation of contact fatigue damage in rails are briefly presented.Calculations of the accumulation of contact-fatigue damages in rails, carried out by the authors, are based on the data on the vertical and horizontal transverse stiffness of intermediate rail fastenings obtained from the results of bench tests. Calculations of the accumulation of contact-fatigue damage were carried out using the “Universal Mechanism” software package. In the process of modeling, four types of intermediate rail fasteners were considered: ARS-4, ZhBR-65Sh, ZhBR-65PShM and W-30. Calculation results were obtained for a curve with a radius of 650 m on a continuous welded track section.
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Zakharov, S. M., and E. V. Torskaya. "Approaches to modeling occurrence of rolling contact fatigue damages in rails." Vestnik of the Railway Research Institute 77, no. 5 (November 13, 2018): 259–68. http://dx.doi.org/10.21780/2223-9731-2018-77-5-259-268.
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Rolling contact-fatigue damages of rails along with their wear are the most common types of rail defects. In recent years, there have been significant changes in the distribution of rolling contact fatigue damages of rails especially on railways operating under heavy haul conditions.This paper is devoted to the overview of approaches to modeling of the occurrence of rolling contact fatigue (RCF) damages on working surfaces of rails. Four types of such approaches to modeling are considered. The first is based on the methods of contact mechanics. To realize it, the vehicle movement on the characteristic sections of the track is modeled, the forces acting in contact are determined, the contact problem is solved, and the values of the linear criterion of contact fatigue damage are determined. The required characteristics of rolling contact fatigue of the rail material are established on the basis of laboratory tests. The second approach uses the diagram of the adaptability of rail material to cyclic loads, proposed by K. Johnson, established on the basis of laboratory tests. The third approach uses criteria that have the physical meaning of the energy released at the contact as an index of the product of the tangential force in contact and relative slippage. In the fourth approach predicting the accumulation of plastic deformation under conditions of cyclic loading is performed on the basis of a series of standard tests of rail steels, including in the welded joint zone, and finite element modeling. In addition, there is also a probabilistic model, based on the assumption that it is possible to transfer the results of the RCF damage of rails on the experimental section of the road to any other site.As the conclusion the authors formulated directions for further studies on the formation and development of surface rolling contact fatigue defects in rails.
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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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Obara, T., N. Kumagai, and T. Takiguchi. "Development of Hybrid Rail Brake." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 209, no. 2 (July 1995): 61–65. http://dx.doi.org/10.1243/pime_proc_1995_209_257_02.
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In Japan three types of rail brake were tested in the field. They were the eddy current rail brake, the electromagnetic rail brake, and the hybrid rail brake. The eddy current type, which does not come into contact with rails, needs high current and greatly increases the temperature in rails. The electromagnetic type which attracts rails and achieves braking by frictional force cannot generate a stable braking force. Therefore the authors developed a hybrid rail brake, which has advantages over the other two types. This type does not need as much current, and keeps rail temperature low.
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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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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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Jalili, Mohammad Mahdi, and Hassan Salehi. "Wheel/rail contact model for rail vehicle dynamics." Comptes Rendus Mécanique 339, no. 11 (November 2011): 700–707. http://dx.doi.org/10.1016/j.crme.2011.07.006.
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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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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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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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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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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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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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Feng, Xiaohe, Shibin Gao, Yang Song, Zeyao Hu, Long Chen, and Tao Liang. "Static and Dynamic Analysis of Conductor Rail with Large Cross-Sectional Moment of Inertia in Rigid Catenary Systems." Energies 16, no. 4 (February 11, 2023): 1810. http://dx.doi.org/10.3390/en16041810.
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The rigid catenary system is widely used in tunnels to power electric trains via contact with a pantograph. Due to gravity, the contact wire normally has a sag that may affect the dynamic interaction performance with a pantograph. To reduce the contact wire sag, the most efficient measure is to improve the moment of inertia of the conductor rail, which is used to clamp the contact wire. Six new types of conductor rail with large moments of inertia are developed based on a conventional conductor rail. Then both the static and dynamic analyses are conducted to investigate the performance of the new types of conductor rail with a big moment of inertia. The conductor rail’s 3D solid finite element model is built using a finite element approach. The vertical deflection and the stress distribution are comparatively analyzed among different types of conductor rail. The analysis results indicate that the vertical deflection and maximum stress are significantly reduced when using the conductor rail with a large moment of inertia. The best performance is observed when the conductor rail of case 1 is used. The maximum sag is reduced by 28.37%, and the maximum stress is decreased by 27.76% compared with the conventional conductor. Finally, a pantograph model is included to evaluate the dynamic performance of the conductor rail with large moments of inertia. The results indicate that contact force fluctuation is significantly reduced after the conductor rails with large moments of inertia are presented. The conductor rail of case 1 shows the best performance, which can reduce the contact force standard deviation by 32% and 27% at speeds of 160 km/h and 200 km/h.
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Amini Sarabi, Mohammad, and Parisa Hosseini Tehrani. "A New Combined Model for considering the Plasticity Effects in Contacting Asperities." Mathematical Problems in Engineering 2020 (November 18, 2020): 1–12. http://dx.doi.org/10.1155/2020/4640204.
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Wheel-rail contact in railway engineering is an important topic. Due to different materials and surface roughness of wheel and rail, the contact characteristics can alter significantly. This article aims to investigate the effects of surface roughness and asperities on the contact parameters such as contact area, contact force, and contact stiffness. The lateral contacts between asperities are assumed to be the general contact condition. Azimuthal and contact angles distributions are assumed to be spherical harmonic distribution. This assumption is compatible with the asperity distribution on the wheel and the rail surfaces. Besides, a new combined model is developed to cover the stick-slip and the plasticity effects in contacting asperities. The results of the presented model offer very good estimations for the asperities contact characteristics, especially at the small-contact area and separation where high-contact pressure and plastic deformation usually exist.
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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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Axinte, Tiberiu. "Hertz Contact Problem between Wheel and Rail." Advanced Materials Research 837 (November 2013): 733–38. http://dx.doi.org/10.4028/www.scientific.net/amr.837.733.
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Rail-wheel contact problems have been analyzed by the use of the three-dimensional finite element models. Based on these models, the paper presents a study regarding the applicability of the Hertz contact to rail-wheel contact problems. Beside a standard rail, the study also considers a crane rail and a switching component. The bodies of the contact problem are the standard rail UIC60 and the standard wheel UICORE. The maximum contact pressure which the material can support in the elastic range in steady state conditions is known as the shakedown limit. With an operating contact pressure below the shakedown limit the rail would be expected to remain elastic a long period of its lifecycle. However, examination of rail cross-sections shows severe plastic deformation in a sub-surface layer of a few tens of microns thickness; the contact patch size is in tens of millimeters. Three-dimensional elastic-plastic rolling contact stress analysis was conducted incorporating elastic and plastic shakedown concepts. The Hertzian distribution was assumed for the normal surface contact load over a circular contact area. The tangential forces in both the rolling and lateral directions were considered and were assumed to be proportional to the Hertzian pressure. The elastic and plastic shakedown limits obtained for the three-dimensional contact problem revealed the role of both longitudinal and lateral shear traction on the shakedown results. An advanced cyclic plasticity model was implemented into a finite element code via the material subroutine. Finite element simulations were conducted in order to study the influences of the tangential surface forces in the two shear directions on residual stresses and residual strains. The Hertz theory is restricted to frictionless surfaces and perfectly elastic solids, but it is the best method for determining deformations and stress from pitch of contact. Form change due to wear and plastic deformation of a rail can reduce the service life of a track. The purpose of this investigation was to study the development of these damage mechanisms on new and three years old rails in a commuter track over a period of two years.
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Hu, Pan, Haitao Wang, Chunlin Zhang, Liang Hua, and Guiyun Tian. "Wheel-Rail Contact-Induced Impact Vibration Analysis for Switch Rails Based on the VMD-SS Method." Sensors 22, no. 18 (September 11, 2022): 6872. http://dx.doi.org/10.3390/s22186872.
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When trains pass through damaged switch rails, rail head damage will change wheel–rail contact states from rolling frictions to unsteady contacts, which will result in impact vibrations and threaten structural safeties. In addition, under approaching and moving away rolling contact excitations and complex wheel–rail contacts, the non-stationary vibrations make it difficult to extract and analyze impact vibrations. In view of the above problems, this paper proposes a variational-mode-decomposition (VMD)-spectral-subtraction (SS)-based impact vibration extraction method. Firstly, the time domain feature analysis method is applied to calculate the time moments that the wheels pass joints, and to correct vehicle velocities. This can help estimate and confine impact vibration distribution ranges. Then, the stationary intrinsic mode function (IMF) components of the impact vibration are decomposed and analyzed with the VMD method. Finally, impact vibrations are further filtered with the SS method. For rail head damage with different dimensions, under different velocity experiments, the frequency and amplitude features of the impact vibrations are analyzed. Experimental results show that, in low-velocity scenarios, the proposed VMD–SS–based method can extract impact vibrations, the frequency features are mainly concentrated in 3500–5000 Hz, and the frequency and peak-to-peak features increase with the increase in excitation velocities.
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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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Ishida, Makoto. "History of Mitigating Rolling Contact Fatigue and Corrugation of Railway Rails in Japan - Review." EPI International Journal of Engineering 1, no. 2 (November 20, 2018): 13–24. http://dx.doi.org/10.25042/epi-ije.082018.02.
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Rail is the one of the most important materials to support and guide railway vehicles safely and smoothly. Since rail suffers from variousinteracting forces and environmental atmosphere, wear and fatigue pose large problems with wheel and rail. Hence, wear and fatigue ofwheel and rail have been studied so far to keep running safety and some level of riding comfort of vehicle taking into account trackmaintenance cost in the world. In this review, the history of theory and practice of rail maintenance in Japanese railways is describedfocusing on rolling contact fatigue (RCF) corrugation of rails caused by dynamic rolling friction at wheel/rail interface. In particular, “squat”mainly callled in UK or “rail surface shelling” called in Japan which is one of typical fatigue phenomenon for steel wheel-on-rail system andrail corrugations caused by dynamic lateral friction and vertical loading at sharp curves and/or long wavelength of rail corrugation causedby longitudinal roll-slip or stick-slip excited by the resonance of unsprung mass of bogie vertical vibration supported by track stiffness. Inaddition, the practice of countermeasure for RCF defect of squat, preventive grinding, and countermeasure for top of low rail corrugation,top of low rail lubrication “Friction Moderating System” are described. Also, the possibility of preventing long wavelength of rail corrugationformed in tangential track in undersea tunnel (salty water) enviornment is described.
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Chen, Y. C. "The effect of proximity of a rail end in elastic-plastic contact between a wheel and a rail." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 217, no. 3 (May 1, 2003): 189–201. http://dx.doi.org/10.1243/095440903769012894.
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This paper investigates the effects of a free rail end on the contact stress distribution near the rail end by employing elastic-plastic finite element methods. The contact elements were used to simulate the interaction between a wheel and a rail. A plane strain model was used in this study. Variations in contact stress fields at various contact points near the rail end were compared. The availability of the Hertz contact theory in the region near the rail end was also investigated. The numerical results indicated that the contact stress distributions around the rail end are sensitive to the contact distance. The location of the maximum von Mises stress was shifted to the contact surface as the contact point moves close to the rail end. Results also show that the plastic zone size and the von Mises stress are increased gradually and extend to the rail end as the contact point moves near the rail end. A higher stress, larger deflection and serious plastic deformation occurring at the rail end may lead to deterioration and delamination at the rail end.
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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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Groβ-Thebing, Arnold, Klaus Knothe, and Klaus Hempelmann. "WHEEL-RAIL CONTACT MECHANICS FOR SHORT WAVELENGTHS RAIL IRREGULARITIES." Vehicle System Dynamics 20, sup1 (January 1992): 210–24. http://dx.doi.org/10.1080/00423119208969399.
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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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YAMASHITA, Shunpei, Motoki YADA, and Hiroyuki SUGIYAMA. "336 Multiple Wheel/Rail Contacts using Constraint Contact Formulations." Proceedings of the Dynamics & Design Conference 2011 (2011): _336–1_—_336–10_. http://dx.doi.org/10.1299/jsmedmc.2011._336-1_.
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Ringsberg, J. "Rolling contact fatigue analysis of rails inculding numerical simulations of the rail manufacturing process and repeated wheel-rail contact loads." International Journal of Fatigue 25, no. 6 (June 2003): 547–58. http://dx.doi.org/10.1016/s0142-1123(02)00147-0.
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PATRA, AMBIKA PRASAD, SUJIT BIDHAR, and UDAY KUMAR. "FAILURE PREDICTION OF RAIL CONSIDERING ROLLING CONTACT FATIGUE." International Journal of Reliability, Quality and Safety Engineering 17, no. 03 (June 2010): 167–77. http://dx.doi.org/10.1142/s0218539310003731.
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Rolling Contact Fatigue (RCF) is a major cause of rail failure leading to replacement of rails. RCF defects are caused by a combination of high normal and tangential stresses between the wheel and rail. In this study, a methodology has been proposed to evaluate P-F (Potential failure-functional failure) interval of RCF defects based on RCF defect rate distribution and fatigue design life distribution. For estimating fatigue design life distribution, load under variable amplitude has been considered which is a case in the mixed traffic scenario. Stochastic S-N curve has been considered to account for probabilistic nature of fatigue life. The stress history can be calculated from the actual load history. RCF defect distribution can be estimated from the probability density function of the defects from the actual field data. The proper estimation of P-F interval will help the infrastructure managers to define rail inspection interval scientifically.
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Lafilé, Vincent, Julie Marteau, Marion Risbet, Salima Bouvier, Pierrick Merino, and Aurélien Saulot. "Characterization of the Microstructure Changes Induced by a Rolling Contact Bench Reproducing Wheel/Rail Contact on a Pearlitic Steel." Metals 12, no. 5 (April 27, 2022): 745. http://dx.doi.org/10.3390/met12050745.
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Understanding the effects of wheel-rail contact on the microstructure of rails is an important issue for railway management. The impact of wheel-rail contact and surface preparation on the microstructure of rails is studied using a rolling contact bench. Microstructure changes are characterized by coupling microhardness measurements and scanning electron microscopy combined with electron backscattering diffraction. This analysis led to a complete description of the sub-surface microstructure in link with the contact conditions. It was found that the use of a corroded layer on the material surface led to a considerable strain-hardening decrease. Lower surface strain-hardening was also found for sliding conditions compared to pure rolling conditions. EBSD characterizations using different indicators highlighted the importance of the scale of investigation: the use of Kernel Average Misorientation led to the identification of larger impacted depths than the Inverse Pole Figures.
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Axinte, Tiberiu. "Analysis of Rails of a Ferry Boat under Wheels Contact Loading." Advanced Materials Research 837 (November 2013): 739–44. http://dx.doi.org/10.4028/www.scientific.net/amr.837.739.
Full textAbstract:
The paper presents the effect of the discontinuity of the rails of a ferry boat and the presence of lower modulus insulation material at the gap to the variations of stresses in the insulated rail. The analysis consists of a three-dimensional wheel rail contact model based on the finite element method. One of the results shows that the maximum stress occurs in the subsurface of the railhead of the ferry boat. The ratio of the elastic modulus of the railhead and insulation material is found to alter the levels of stress concentration. Numerical result indicates that a higher elastic modulus insulating material can reduce the stress concentration in the railhead but will generate higher stresses in the insulation material, leading to earlier failure of the insulation material. A general subsurface crack propagation analysis methodology is used for the wheel and rail rolling contact. The fatigue damage in the wheel is calculated using a previously developed mixed-mode fatigue crack propagation model. The advantages of the proposed methodology are that it can accurately represent the contact stress of complex mechanical components and can consider the effect of loading non-proportionality. The effects of wheel diameter, vertical loading amplitude, initial crack size, location and orientation on stress intensity factor range are investigated using the proposed model. The prediction results of the proposed methodology are compared with in field observations. The contact elements were used to stimulate the interaction between a wheel and a railhead. Variations in contact stress fields at various locations of the rail are sensitive to the contact distance. The location of the maximum von Mises stress was shifted to the contact surface as the contact point moves close to the rail end. A higher stress, larger deflection and significant plastic deformation occurring at the rail from ferry boat may lead to deterioration at the rail end.