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1
Zhang, Tie, Jun Zhang i Chuan Xi Sun. "The Profile Analysis of Wheels and Rails of Different Wear Stages for Heavy-Haul Wagons". Applied Mechanics and Materials 602-605 (sierpień 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.
2
Ma, He, Jun Zhang i Xiu Juan Zhang. "The Calculation and Analysis for the Independent Wheels of Tramcar". Applied Mechanics and Materials 577 (lipiec 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
Milošević, Miloš, Aleksandar Miltenović, Milan Banić i Miša Tomić. "DETERMINATION OF RESIDUAL STRESS IN THE RAIL WHEEL DURING QUENCHING PROCESS BY FEM SIMULATION". Facta Universitatis, Series: Mechanical Engineering 15, nr 3 (9.12.2017): 413. http://dx.doi.org/10.22190/fume170206029m.
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Residual stresses of the rail wheels are influenced by heat treatment during the manufacturing process. The quenching process during the manufacturing results in the residual stresses within the rail wheel that may be dangerous for the rail wheel during its operation. Determination of the residual stress in the rail wheel is important for understanding the damage mechanisms and their influence on the proper work of rail wheels. This paper presents a method for determining the residual stresses in the rail wheel during the quenching process by using the directly coupled thermal-structural analysis in ANSYS software.
4
Liu, Kai, i 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, nr 10 (4.12.2019): 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.
5
Kumar, S., i S. P. Singh. "Rail Head Geometry, Rail Rolling and Wheel-Rail Contact Tilting Analysis for Heavy Axle Loads". Journal of Engineering for Industry 111, nr 4 (1.11.1989): 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.
6
Kumar, S., i S. P. Singh. "Heavy Axle Load Wheel-Rail Contact Stresses and Their Tread-Crown Curvature Relationships". Journal of Engineering for Industry 111, nr 4 (1.11.1989): 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.
7
Axinte, Tiberiu. "Analysis of Rails of a Ferry Boat under Wheels Contact Loading". Advanced Materials Research 837 (listopad 2013): 739–44. http://dx.doi.org/10.4028/www.scientific.net/amr.837.739.
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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.
8
Gu, Shao Jie, Xin Wen Yang i 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 (wrzesień 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.
9
Akeel, N. A., M. A. Aziman, Zainuddin Sajuri, Ahmad Kamal Ariffin i A. W. Ikhsan. "Identification of Damages and Stress Analysis of Rail/Wheel Rolling Contact Region". Key Engineering Materials 462-463 (styczeń 2011): 1152–57. http://dx.doi.org/10.4028/www.scientific.net/kem.462-463.1152.
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This paper presents the identification of damages and stress analysis of rail/wheel rolling contact region. The railhead surface of used rail track was investigated to identify damages and the hardness of the rail/wheel contact area was measured. Finite element method FEM code, ANSYS was used to determine the stress distribution at vicinity of rail/wheel contact area. The results showed that the hardness increased on the contact area between rail and wheel due to repeated rolling contact of rail and wheel surface. Severe damages and cracks were observed on the railhead surface and in the cross section of the rail at the contact region. The FEM simulation showed that the highest stress distribution regions were matched with the area of severely damage and high hardness obtained from the observation and experimental results.
10
Wu, Feng Qi, Jin Zhang i Wen Qing Yao. "Crane Wheel-Rail Contact Stresses Research Based on Experimental Test and Finite Element Analysis". Applied Mechanics and Materials 496-500 (styczeń 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..
11
Han, Liangliang, Lin Jing i Longmao Zhao. "Finite element analysis of the wheel–rail impact behavior induced by a wheel flat for high-speed trains: The influence of strain rate". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, nr 4 (18.04.2017): 990–1004. http://dx.doi.org/10.1177/0954409717704790.
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The wheel–rail impact response induced by a wheel flat for high-speed trains is simulated numerically, based on the strain rate-dependent constitutive parameters of wheel–rail materials, using the finite element software LS-DYNA explicit algorithm. Influences of the speed of the train, the length of the wheel flat, and axle load on the wheel–rail impact behavior are discussed over a wide range, in terms of the vertical impact force, von Mises equivalent stress, shear stress, and equivalent plastic strain. The maximum wheel–rail impact forces are 2.6–4.4 times greater than the corresponding static axle loads due to the presence of a wheel flat. The maximum von Mises equivalent stress and equivalent plastic strain have occurred on the wheel–rail contact surface, while the maximum xy shear stress has often occurred on the subsurface of 4–6 mm below the contact surface. The wheel–rail impact responses induced by a wheel flat are sensitive to the speed of trains, flat length, and axle load. Besides, the strain rate effect of wheel–rail materials has a significant influence on the maximum von Mises equivalent stress, shear stress, and equivalent plastic strain, while it has no influence on the maximum vertical impact force. These findings are very helpful to guide the maintenance and repair of wheel–rail components in rail transport.
12
Song, Du, Zhang i Sun. "Evaluating the Effect of Wheel Polygons on Dynamic Track Performance in High-Speed Railway Systems Using Co-Simulation Analysis". Applied Sciences 9, nr 19 (4.10.2019): 4165. http://dx.doi.org/10.3390/app9194165.
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With increases in train speed and traffic density, problems due to wheel polygons and those caused by wheel–rail impacts will increase accordingly, which will affect train operational safety and passenger ride comfort. This paper investigates the effects of polygonal wheels on the dynamic performance of the track in a high-speed railway system. The wheel–rail interaction forces caused by wheel polygons are determined using a dynamic vehicle–track model, and the results are entered into a slab track finite element model. The influence of the harmonic order and out-of-roundness (OOR) amplitude of wheel polygons on the transient dynamic characteristics of the track(von Mises equivalent stress, displacement, and acceleration) is examined under high-speed conditions. The results indicate that the vibration acceleration and von Mises equivalent stress of the rail increase in proportion to the harmonic order and the OOR amplitude and velocity of a polygonized wheel. The vibration displacement of the rail first increases and then decreases with a change in the harmonic order, and reaches a maximum at the ninth order. The dynamic responses of the concrete slab layer, cement-asphalt layer, and support layer increase linearly with the harmonic order and amplitude of wheel polygons and decrease from top to bottom. Through a combination of numerical simulations and real-time monitoring of rail vibrations, this study provides guidance on potential sensor locations to identify polygonized wheels before they fail.
13
Zhou, Jian Hua, Yu Ji, An Chao Ren i 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 (lipiec 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.
14
Seo, Jung Won, Byeong Choon Goo, Heung Chai Chung, Jae Boong Choi i Young Jin Kim. "The Effects of Residual Stress of Contact Fatigue Life for Railway Wheels". Key Engineering Materials 297-300 (listopad 2005): 115–21. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.115.
Pełny tekst źródłaStreszczenie:
Railway wheels and axles belong to the most critical components in railway vehicles. The service conditions of railway vehicles became more severe in recent years due to the increase of speed. Therefore, a more precise evaluation of railway wheel life and safety has been requested. Wheel/rail contact fatigue and thermal cracks due to braking are two major mechanisms of the railway wheel failure. One of the main sources of the contact zone failure is the residual stress. The residual stress on wheel is formed during the manufacturing process which includes a heat treatment, and then, is changed in the process of braking which results in wheel/rail contact stress and thermal stress. In this paper, an evaluation procedure for the contact fatigue life of railway wheel including residual stress is proposed. Also, the cyclic stress history for fatigue analysis is simulated by applying finite element analysis for the moving contact load. As a result, a fatigue life estimation methodology is proposed for railway wheels which includes the effects of residual stresses due to heat treatment, braking and repeated contact load, respectively.
15
Chen, Dilai, Gang Shen, Xin Mao i Buchen Chen. "A Design Method for Rail Profiles in Switch Panel of Turnout Based on the Contact Stress Analysis". Shock and Vibration 2020 (9.10.2020): 1–15. http://dx.doi.org/10.1155/2020/8575498.
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Contact stress between wheel and rail is believed to cause damage to the rail. The relationship between the contact stress and the radius of the rail is initially based on the Hertz contact theory. By adjusting its radius, the rail profile is designed with an objective of reducing the maximal contact stress between wheel and rail. The rail profile of turnout is parameterized by defining several control cross sections along the switch. The experiment of dynamic vehicle-turnout interaction is also carried out to investigate the effect of the improved rail profile on the dynamical behavior of the vehicle. The method is then verified through examples using rail profile with a switch width of 20 mm and LM worn-type tread at the CN60-350-1:12 turnout. The results show that the designed rail has a higher matching degree with the wheel profile. It can reduce the contact stress, improve the wheel-rail contact state, and prolong the service life of the rail without deteriorating the dynamic performance of the vehicle passing through the turnout.
16
Han, Feng, Hao Wei i Yang Liu. "Thermal–Mechanical Coupling Analysis of Wheel–Rail Sliding Friction under Two-Point Contact Conditions". Lubricants 11, nr 5 (22.05.2023): 232. http://dx.doi.org/10.3390/lubricants11050232.
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The generation of wheel–rail-sliding frictional heat is often accompanied by transverse displacement of a wheel. To study the thermal problem of wheel–rail sliding friction at two-point contact, this paper uses an LM tread wheel and a 60 kg·m−1 rail as examples. A thermal–mechanical-coupled finite-element model of equal proportion wheel–rail sliding is established. A direct-coupling method is used to analyze the thermal–mechanical coupling of the wheel–rail interface under sliding contact. This model considers the temperature-dependent material properties and boundary conditions, such as thermal convection and thermal dissipation, in the process of nonstationary frictional-heat conduction. Firstly, the effects of different sliding speeds, axle loads, and contact modes on the temperature and stress fields of the contact area are analyzed. Then, the lubrication and cooling effects of friction modifiers on the rail top and rail gauge angle are compared. The results show that, at a sliding speed of 2 m/s and an axle load of 30 t under a sliding condition of 200 mm, on the top and side of the rail, the temperatures at the contact patch centers are 813 °C and 547.7 °C, respectively. Under different operating conditions, the rail-side temperature is 55–75% of that of the temperature at the rail top, and the rail-side contact and friction stress values are 76–96% of those at the rail top. This indicates that frictional thermal damage on the rail side cannot be ignored. With a lower sliding speed, the thermal response of the two contact patches is closer. The impact of axle load on the frictional temperature and stress on the rail side is more critical than the sliding speed. The optimal lubrication choice is overall lubrication, which can decrease the rail top temperature by 47.2% and frictional stress by 56.2%, as well as decreasing the rail side temperature by 70.3% and frictional stress by 77.4%.
17
Tiago Cruz Tepedino, Marcelo Leite Ribeiro i Gustavo Tressia. "Effect of rail cant on stress distribution". World Journal of Advanced Engineering Technology and Sciences 9, nr 1 (30.06.2023): 372–86. http://dx.doi.org/10.30574/wjaets.2023.9.1.0184.
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The rail cant is an important geometry parameter and is commonly monitored to ensure railway safety and comfort conditions. Understanding the influence of cant variation on the performance of railway components is extremely important to define the tolerance limits of the track and adequacy of maintenance plans. There are numerous rail cant patterns on railways, 1:40, 1:30, 1:20. However, the optimal rail cant to reduce the stress and wear of rail head not been extensively studied. This work performs an analysis of the effect of the rail cant on the rail head stress distribution. To investigate stress and strain in rail head, a Finite Element Model with Ansys software was used. For the analysis was considered a 136RE rail, axle load of 32 ton and AAR-1B wheel profile. The rail cant was varied in 0, 1:20 and 1:40. The results show that the stress in rail and wheel increases with the rail cant. The maximum stress occurred in the condition with rail cant of 1:20. The variation of cant from 0 to 1:20 results in a decrease of approximately 9% in maximum stress, ranging from 947 MPa to 867 MPa. The wheel/rail contact in cant zero condition occurred close to the transition of the wheel tread and the beginning of flange root, resulting in a dynamic instability in the wheelset. In addition to higher contact stress, increases the propensity for the hutting phenomenon, which can accelerate rail and wheel wear
18
Kumar, S., P. K. Krishnamoorthy i D. L. Prasanna Rao. "Influence of Car Tonnage and Wheel Adhesion on Rail and Wheel Wear: A Laboratory Study". Journal of Engineering for Industry 108, nr 1 (1.02.1986): 48–58. http://dx.doi.org/10.1115/1.3187041.
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This study presents the results and analysis of a laboratory investigation, of rail and wheel wear under clean and dry tangent track conditions, utilizing the IIT-GMEMD quarter scale simulation facility. Important factors influencing rail degradation are discussed followed by five different load/lubrication classifications of contacts. Influence of two important parameters, viz. wheel load (N) and adhesion coefficient of the tractive wheels (μ), on rail and wheel wear has been studied under conditions of Hertzian simulation. Seven separate experiments were conducted to measure wear of rail and nontractive freight car wheels. These were followed by six additional wear tests, simulating a typical U.S. locomotive, to investigate the effect of adhesion coefficients. The wear rates for tonnages* exceeding 65–70 t car increase at a much higher rate than those for tonnages below 65 t. Nonlinear relationship showing wear rate proportional to N5.4 and a bilinear relation have been developed. Considerations of contact plasticity show that the stress corresponding to 68-t freight load is a threshold stress which when exceeded leads to continual plasticity of new rails thus preventing shakedown. The influence of adhesion coefficient is also quite nonlinear, the wear rates being much higher for μ > 0.3. Photomicrographs of the surfaces of the wheel and rail at the end of the tests showed mild wear for μ ≤ 0.25 and severe wear for μ ≥ 0.35 indicating a transition of wear mechanism from mild to severe slightly above μ = 0.25. Wear rate is found to be approximately proportional to the square of the adhesion coefficient. A bilinear relation of wear rate versus μ, which is more accurate, is also given. It was observed that the effect of adhesion is more severe than the effect of tonnage alone. However, the tonnage effect is of serious consequence regarding plastic shakedown of the rails. A formulation of wear rate as a combined function of tonnage and adhesion coefficient is given. The urgent need for a solution of this problem is pointed out.
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Coo, Byeong-Choo, i Young-Jin Lee. "Railway Vehicle Wheel Restoration by Submerged Arc Welding and Its Characterization". Sci 1, nr 1 (17.04.2019): 25. http://dx.doi.org/10.3390/sci1010025.
Pełny tekst źródłaStreszczenie:
When a railway vehicle moves on a curved rail, sliding contact occurs between the rail head side and wheel flange, which wears the wheel flange down. The thinned flange needs to be restored above the required minimum thickness for structural safety. In this study, a new process and welding wire for restoring worn-out railway wheels by submerged arc welding was developed. To characterize the properties of the restored wheel, dilatometric analysis of phase transformation, SEM/EDX analyses, hardness measurement, and residual stress measurement using the X-ray diffraction method were performed. Finally, wear tests with full-size wheel/rail specimens were carried out. It was confirmed that the weld metal was composed of bainitic microstructures as intended, and welding defects were not observed. The wear amount of the restored wheel was greater than that of the base material, but it was less than half of the wear depth of the weld-repaired wheel with ferritic–pearlitic microstructures. The developed process seems applicable to industry.
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Coo, Byeong-Choo, i Young-Jin Lee. "Railway Vehicle Wheel Restoration by Submerged Arc Welding and Its Characterization". Sci 1, nr 2 (4.09.2019): 52. http://dx.doi.org/10.3390/sci1020052.
Pełny tekst źródłaStreszczenie:
When a railway vehicle moves on a curved rail, sliding contact occurs between the rail head side and wheel flange, which wears the wheel flange down. The thinned flange needs to be restored above the required minimum thickness for structural safety. In this study, a new process and welding wire for restoring worn-out railway wheels by submerged arc welding was developed. To characterize the properties of the restored wheel, dilatometric analysis of phase transformation, SEM/EDX analyses, hardness measurement, and residual stress measurement using the X-ray diffraction method were performed. Finally, wear tests with full-size wheel/rail specimens were carried out. It was confirmed that the weld metal was composed of bainitic microstructures as intended, and welding defects were not observed. The wear amount of the restored wheel was greater than that of the base material, but it was less than half of the wear depth of the weld-repaired wheel with ferritic–pearlitic microstructures. The developed process seems applicable to industry.
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Coo, Byeong-Choo, i Young-Jin Lee. "Railway Vehicle Wheel Restoration by Submerged Arc Welding and Its Characterization". Sci 2, nr 2 (14.05.2020): 33. http://dx.doi.org/10.3390/sci2020033.
Pełny tekst źródłaStreszczenie:
When a railway vehicle moves on a curved rail, sliding contact occurs between the rail head side and wheel flange, which wears the wheel flange down. The thinned flange needs to be restored above the required minimum thickness for structural safety. In this study, a new process and welding wire for restoring worn-out railway wheels by submerged arc welding was developed. To characterize the properties of the restored wheel, dilatometric analysis of phase transformation, SEM/EDX analyses, hardness measurement, and residual stress measurement using the X-ray diffraction method were performed. Finally, wear tests with full-size wheel/rail specimens were carried out. It was confirmed that the weld metal was composed of bainitic microstructures as intended, and welding defects were not observed. The wear amount of the restored wheel was greater than that of the base material, but it was less than half of the wear depth of the weld-repaired wheel with ferritic–pearlitic microstructures. The developed process seems applicable to industry.
22
Huo, Junzhou, Hanyang Wu, Dong Zhu, Wei Sun, Liping Wang i Jianghui Dong. "The rigid–flexible coupling dynamic model and response analysis of bearing–wheel–rail system under track irregularity". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, nr 21 (12.12.2017): 3859–80. http://dx.doi.org/10.1177/0954406217745336.
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As the main bearing components of vehicle wheel/rail systems, railway bearings take on the main load of wheel/rail system. These bearings can be easily damaged after a long-term load, which causes vibrations and significant deterioration of force distribution and directly affects the driving stability of the locomotive. Current systems available for modeling the dynamics of wheel/rail systems rarely consider nonlinear contact load bearing, which causes errors in the calculation of wheel/rail system dynamics. According to the bearing structure characteristics and working features of a specific system, this paper thoroughly evaluates the flexible deformation of shaft and bearing, time-varying nonlinear contact load, track irregularity, and bearing to establish a wheel/rail system coupling dynamics model. Then, based on the coupling dynamics theoretical model, the wheel/rail system’s coupling nonlinear dynamic characteristics are studied under random load. Then, this theoretical model of the wheel–bearing–rail system dynamics is verified using the railway bearing as an example. Finally, the model is applied to the process of rail/wheel low force design. Results show that under irregular stimulation, the maximum contact load increased by 71.2% and the maximum contact stress increased by 19.6%. After moderate wear, the wheel/rail system vibration and loading condition deteriorate rapidly. Under the low rail/wheel force, the wheel tread and diameter had significant effects on wheel/rail contact force distribution. The rail specifications are found to affect the wheel/rail system’s vibration significantly. This paper has important theoretical value and practical significance for developing reliable railway bearings and wheel/rail systems with good static/dynamic characteristics that can withstand dynamic impact load.
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Lisowski, Filip, i Edward Lisowski. "Optimization of ER8 and 42CrMo4 Steel Rail Wheel for Road–Rail Vehicles". Applied Sciences 10, nr 14 (8.07.2020): 4717. http://dx.doi.org/10.3390/app10144717.
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Railway track maintenance services aim to shorten the time of removing failures on the railways. One of the most important element that shorten the repair time is the quick access to the failure site with an appropriate equipment. The use of road-rail vehicles is becoming increasingly important in this field. In this type of constructions, it is possible to use proven road vehicles such as self-propelled machines or trucks running on wheels with tires. Equipping these vehicles with a parallel rail drive system allows for quick access to the failure site using both roads and railways. Steel rail wheels of road-rail vehicles are designed for specific applications. Since the total weight of vehicle is a crucial parameter for roadworthiness, the effort is made to minimize the mass of rail wheels. The wheel under consideration is mounted directly on the hydraulic motor. This method of assembly is structurally convenient, as no shafts or intermediate couplings are required. On the other hand, it results in strict requirements for the wheel geometry and can cause significant stress concentration. Therefore, the problem of wheel geometry optimization is discussed. Consideration is given to the use of ER8 steel for railway application and 42CrMo4 high-strength steel. Finite element analysis within Ansys software and various optimization tools and methods, such as random tool, subproblem approximation method and first-order method are applied. The obtained results allow to minimize the rail wheel mass with respect to the used material. Moreover, computational demands and methods leading to the best results are compared.
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Kossov, V. S., A. V. Savin i O. G. Krasnov. "On the Issue of Determining Relative Rail Rolling Contact Fatigue Damageability". World of Transport and Transportation 19, nr 1 (8.09.2021): 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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Sung, Ki Deug, Tae Hyeok Yun, Geun Sun Lee i Ki Hong Kim. "A Study on the Stress Analysis and Optimum Design of S-Shape Wheel for Rolling Stock". International Journal of Modern Physics B 17, nr 08n09 (10.04.2003): 1953–58. http://dx.doi.org/10.1142/s0217979203019939.
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The mechanical stress due to the wheel-rail contact and thermal stress due to the drag braking increase the incidence of wheel failure. So, firstly, stress analyses(mechanical, thermal and combined stress) of wheel plate are performed using 3-dimensional finite element method(FEM). Secondly, the optimum design of wheel plate is investigated in order to reduce weight of the wheel based on results of stress analysis. The optimum design is performed using 2-dimensional axisymmetric F.E. model and its results are verified by 3-dimensional F. E. analysis.
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Wang, Zhiqiang, i Zhenyu Lei. "Analysis of Rail Corrugation Characteristics on High-Speed Rail Based on Transient Finite Element Method". International Journal of Acoustics and Vibration 26, nr 3 (30.09.2021): 231–39. http://dx.doi.org/10.20855/ijav.2021.26.31778.
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By using the transient finite element method, a three-dimensional wheelset-track coupled rolling contact model for high-speed rail is established, and the rationality and effectiveness of the model are verified by field measurements. Next, the wheel-rail contact stress states and relative slip characteristics are calculated and analyzed to reveal the cause of inner rail corrugation. Then, the vertical vibration acceleration of the rail/wheel is taken as the output variable to study the dynamic responses of the wheelset-track system. Finally, the parameter sensitivity analysis is carried out. The results show that the maximum normal/tangential contact stress between the inner wheel and inner rail is greater than that between outer wheel and outer rail due to the unbalanced load of inner rail caused by the excess superelevation of track structure, which indicates that the unbalanced load of the inner rail may aggravate the development of rail wear, and the rationality of the model established in this paper is verified. The wheel-rail relative slip region on the inner rail side appears periodically, and the distance between the two adjacent slip regions is close to the characteristic wavelength of the measured inner rail corrugation, which illustrates that the periodic variation of slip regions on the inner rail surface plays an important role in the formation of rail corrugation, and the validity of the model is verified. The periodic distribution of wheel-rail relative slip regions on the outer rail surface is not obvious, demonstrating that the outer rail tends to form uniform wear, which is consistent with the fact that the outer rail corrugation is slight in the measured section. The wheelset-track system has been in the process of unstable continuous oscillation in the analysis interval, combined with the analysis results of the wheel-rail relative slip characteristics, it can be concluded that the unstable self-excited vibration of wheelset-track system under the condition of tangential contact force reaching saturation is the main cause of rail corrugation. The dominant characteristic frequencies of vertical vibration accelerations of rail and wheel are all 561 Hz, the corresponding characteristic wavelength (148 mm) is close to the distance (150 mm) between the calculated adjacent slip regions, and is also close to the characteristic wavelengths (125 mm and 160 mm) of inner rail corrugation, which shows that the resonance phenomenon occurs in the wheelset-track system at the above frequency, thus leading to the increase of dynamic responses of wheelset-track system. The fastener vertical stiffness and wheel-rail coefficient of friction have significant effect on the development of rail corrugation, and the running speed determines the occurrence probability of inner/outer rail corrugation by affecting the track superelevation state.
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Peixoto, D. F. C., L. A. A. Ferreira i Paulo Manuel Salgado Tavares de Castro. "Application of the Dang Van Fatigue Criterion to the Rail/Wheel Contact Problem". Materials Science Forum 636-637 (styczeń 2010): 1178–85. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.1178.
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Great interest is dedicated to the wheel/rail contact problem, in particular as a result of some accidents worldwide and also in Portugal. In the present work a three dimensional finite element analysis of the wheel/ rail contact problem was performed using the software ABAQUS. A preliminary study on simpler geometries was carried out, in order to identify the solution strategies giving more accurate solutions. The influence of mesh refinement, friction coefficient, and numerical techniques as Lagrange and penalty functions were analysed in the simpler cases of contact of two cylinders along a generatrix, and the contact of a cylinder and a rigid plane. The corresponding Hertz solutions were programmed using MATLAB in order to compare with the finite element analyses. The numerical procedures giving better results were later applied to the wheel/rail contact problem, using standard rail and wheels profiles used by the Portuguese Railways company (CP). The influence of small geometry variations on the stress analysis results was then studied, and the study of initiation of defects using the Dang Van fatigue criterion was performed.
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Xiao, Qian, Yihang Yang, Chao Chang i Dongzhe Li. "Monitoring and Evaluation of High-Speed Railway Turnout Grinding Effect Based on Field Test and Simulation". Applied Sciences 13, nr 16 (11.08.2023): 9177. http://dx.doi.org/10.3390/app13169177.
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Turnouts are the weak spot in high-speed rail systems, and it is simple for the phenomenon of the wheel–rail force and the carbody lateral acceleration over-limit to arise when the train passes through, which affects the service life of the rail and the running stability of the train. In this paper, the turnout with wheel–rail force over-limit and carbody lateral acceleration over-limit is selected for analysis, and the profiles of the wheel and rail are monitored. Then, the vehicle–turnout coupled multi-body dynamics model is simulated. Additionally, the portable vibration analyzer, the comprehensive inspection train, and the wheel–rail contact dynamic stress tester monitors the data and evaluates the impact of rail grinding on high-speed railway. The results of this study demonstrated that the turnout profiles are in good agreement with the standard wheel profiles following grinding, and the wheel–rail contact point and equivalent conicity both improved. When the train passes the ground turnout at high speed with and without the wheel polygonal wear, the wheel–rail force and the carbody acceleration were clearly improved. Using the wheel–rail contact dynamic stress tester, the comprehensive inspection train, and the portable vibration analyzer monitoring the changes in the carbody acceleration, the wheel–rail force and the carbody acceleration are definitely better after grinding. Similar to the pattern in the simulation, the train’s running steadiness increased by grinding.
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Goo, Byeong Choon, i Jung Won Seo. "Finite Element Analysis of the Rolling Contact Fatigue Life of Railcar Wheels". Materials Science Forum 575-578 (kwiecień 2008): 1461–66. http://dx.doi.org/10.4028/www.scientific.net/msf.575-578.1461.
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Railcar wheels and axles belong to the most critical components in railway vehicles. The service conditions of railway vehicles have been more severe in recent years due to speed-up. Therefore, a more precise evaluation of railcar wheel life and safety has been requested. Wheel/rail contact fatigue and thermal cracks due to braking are two major mechanisms of the railcar wheel failure. One of the main sources influencing on the contact zone failure is residual stress. The residual stress in wheels formed during heat treatment in manufacturing changes in the process of braking. Thus the fatigue life of railcar wheels should be estimated by considering both thermal stress and rolling contact. Also, the effect of residual stress variation due to manufacturing process and braking process should be included in simulating contact fatigue behavior. In this paper, an evaluation procedure for the contact fatigue life of railcar wheels considering the effects of residual stresses due to heat treatment, braking and repeated contact load is proposed. And the cyclic stressstrain history for fatigue analysis is simulated by finite element analysis for the moving contact load.
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Kulkarni, S. M., G. T. Hahn, C. A. Rubin i V. Bhargava. "Elasto-Plastic Finite Element Analysis of Repeated Three-Dimensional, Elliptical Rolling Contact With Rail Wheel Properties". Journal of Tribology 113, nr 3 (1.07.1991): 434–41. http://dx.doi.org/10.1115/1.2920643.
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This paper presents an elasto-plastic analysis of the repeated, frictionless, three-dimensional rolling contact similar to the ones produced by the rail-wheel geometry. This paper treats an elliptical contact rolling across a semi-infinite half space. The contact shape and loading: semi-major axis (in the rolling direction), w1 = 8 mm, and semi-minor axis, w2 = 5.88 mm, reflect standard rail and wheel curvatures and a wheel load of 149 KN (33,000 lb). A three-dimensional, elasto-plastic finite element model, developed earlier, is employed together with the elastic-linear-kinematic-hardening-plastic (ELKP) idealization of the cyclic plastic behaviour of a material similar to rail and wheel steels. The calculations present the displacements, the stress-strain distributions, stress-plastic strain histories and the plastic strain ranges in the half-space. The cyclic plasticity approaches a steady state after one contact with further contacts producing open but fully reversed stress-strain hysteresis loops, i.e., plastic shakedown.
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Pun, Chung Lun, Qian Hua Kan, Peter J. Mutton, Guo Zheng Kang i Wen Yi Yan. "On the Evaluation of the Stress State in Rail Head for Assessing Fatigue Resistance". Advanced Materials Research 891-892 (marzec 2014): 1157–62. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.1157.
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To search for a single parameter to evaluate the stress state in rail head during wheel/rail rolling contact situations, the stress-based and the strain based phenomenological approaches for multiaxial fatigue analysis can be considered as the candidates. Following the stress-based approach, the maximum von Mises stress range can be applied as a single parameter to evaluate the stress state in the rail head. However, the von Mises stress range only relies on the stress field in the rail head for the fatigue analysis, which is not sufficient for assessing the fatigue resistance of the rail steel. The Smith-Watson-Topper (SWT) method, the strain-based phenomenological approach for multiaxial fatigue analysis which considers stress, elastic strain and plastic strain components, is then adopted to study rolling contact fatigue in the rail head. Combining with the three-dimensional finite element modelling of a steady-state wheel/rail rolling contact, the numerical procedure to calculate the SWT parameter in the rail head is presented. The capability of the SWT method to predict the initiation of fatigue cracks in the rail head is confirmed in a case study. Consequently, the maximum SWT parameter is proposed as a single parameter to effectively evaluate the stress state in the rail head.
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Jelila, Y. D., H. G. Lemu, W. Pamuła i G. G. Sirata. "Fatigue life analysis of wheel-rail contacts at railway turnouts using finite element modelling approach." IOP Conference Series: Materials Science and Engineering 1201, nr 1 (1.11.2021): 012047. http://dx.doi.org/10.1088/1757-899x/1201/1/012047.
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Abstract The article deals with wheel-rail contact analysis at railway turnout using a finite element modelling approach. The focus is understanding the wheel-rail contact problems and finding the means of reducing these problems at railway turnouts. The main aim of the work reported in this article is to analyse fatigue life and simulate the wheel-rail contact problems for a repeated wheel loading cycle by considering the effect of normal and tangential contact force impact under different vehicle loading conditions. The study investigates the impact of tangential contact force generated due to different-angled shapes of the turnout and aims to reveal how it affects the life of contacting surfaces. The obtained results show that the maximum von-Mises equivalent alternating stress, maximal fatigue sensitivity, and maximum hysteresis loop stresses were observed under tangential contact force. These maximum stresses and hysteresis loops are responsible for rolling contact fatigue damage, and excessive deformation of the wheel-rail contact surface. At a constant rotational velocity, the tangential contact force has a significant impact on the fatigue life cycle and wheel-rail material subjected to fatigue damage at lower cycles compared to the normal contact force. The finite element modelling analysis result indicated that the contact damages and structural integrity of the wheel-rail contact surface are highly dependent on contact force type and can be affected by the track geometry parameters.
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Krotov, Sergey, i Dmitriy Kononov. "Analysis of Contact Zone of Railway Wheel and Rail". Proceedings of Petersburg Transport University 19, nr 2 (22.06.2022): 221–31. http://dx.doi.org/10.20295/1815-588x-2022-19-2-221-231.
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Purpose: Investigation of stresses on contact surface during interaction of a railway wheel and rail from normal pressure and tangential forces in the presence of adhesion and sliding zones of different sizes. Methods: Formulas for equivalent and tangential stresses for plane deformation and plane stress state are given and used for calculations. Special attention is paid to the study of stress state at contact boundary points of cylinders, which parameters are calculated for at contact surface points at boundary between sliding and adhesion zones. Results: The study of the distribution of equivalent stresses in the zone of their maximal values is carried out, the dependence from friction coefficients is established. The distribution of stresses on contact surface of a drive cylinder from normal pressure and from contact tangential forces in the presence of adhesion and slippage zones for different ratios between them is shown. The obtained results revealed the increase in stresses at the boundaries of sliding and adhesion sections, the effect of absence of tangential forces or presence of complete slippage. Practical importance: The data make it possible to predict more accurately a decrease in the contact-fatigue durability of samples and can be useful in studying the appearance of microcracks of a wheel or rail during their interaction. Physical modeling of the interaction of rolling elements, such as a rail and a wheel, which is performed at actual work loads, interaction speeds, various friction coefficients, at sliding or adhesion recreates with certain reliability actual conditions of interaction of a wheel and a rail, and the results help to predict the reliability of a wheel-rail pair in railway transport.
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Axinte, Tiberiu. "Finite Elements Analysis of the Rail-Wheel Rolling Contact". Advanced Materials Research 1036 (październik 2014): 559–63. http://dx.doi.org/10.4028/www.scientific.net/amr.1036.559.
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The railway transportation system is nowadays one of the most important systems for land transport because its increased load carrying capacity, high speed, low costs, connectivity and ecologic features. As a result, the railways are subjected to additional loads which produce a higher level of strains and stresses. The rolling contact of a wheel on a rail is the basis of many rail-wheel related problems including the rail corrugation, wear, plastic deformation, rotating interaction fatigue, thermo-elastic-plastic behavior in contact, fracture, creep, and vehicle dynamics vibration. Therefore, this topic became the research subject for many researchers worldwide. Practical experience shows that the stress distribution is an important factor at the rail-wheel contact interfaces, that is, two materials in contact at rolling interfaces which are highly influenced by the geometry of the contacting surfaces, material constants, loads and boundary conditions. Three different procedures have conventionally been utilized to inspect rail-wheel contacts including Hertzs theory and Kalkers analytical method. The calculation of these stresses becomes much more complicated in three dimensional real size geometries. For this reason, many scientists have simplified the problem mainly by means of theoretical or numerical approaches based on the Hertzs theory, which can be considered the starting point of all subsequent researches. Both static and dynamic contact stresses have been carefully examined. Accurate theories, as well as computer software have been developed to evaluate all the parameters which influence the rail-wheel interaction. The analytical equations were employed to calculate the Hertzian stresses using the Octave software. For these elements, the simplifying hypothesis was to consider only the elastic properties of materials and, consequently, to neglect the elastic-plastic characteristics. Besides, many models generally neglected the friction coefficient between the rail and wheel, which is one of the most critical factors in determining the precise amount of stresses and distribution of contact pressure in rail-wheel contact area. On the other hand, some practical methods have also been introduced to solve traditional problems related to rail-wheel interaction. Other original contribution of this research is to create a precise finite element model of a 3D rail-wheel, axle and pads in order to evaluate stresses, strains, and contact forces in this complex interaction system. However, unlike many previous works, this study focuses on the real conditions of the problem including exact boundary and loading conditions, using real-size complete model of various components with precise shapes.
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Lack, Tomáš, i Juraj Gerlici. "Y25 freight car bogie models properties analysis by means of computer simulations". MATEC Web of Conferences 157 (2018): 03014. http://dx.doi.org/10.1051/matecconf/201815703014.
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The article deals with the results of the simulation analysis of a railway wagon bogie model. We analysed four freight wagon bogie variants for its dynamics properties research. The bogie models correspond in general to the Y25 bogie concept. The models were created in SIMPACK software enhanced by the RAIL module. From the research results depicted in the graphs we found out, that the newly designed bogie variant gives the best results when compared to the other analysed versions. The newly designed model consists of a standard Y25 bogie frame with two Lenoire friction dampers. This bogie is equipped with longitudinal linkages on both sides. These linkages are completed with a radial torsion binding, torsion rod, between side bogie parts. The contact of railway wheels and rails generates active forces affecting the surface contact, affecting the size of the normal and tangential stress, wear surfaces of the wheel/rail, or directly the size of the derailment.
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Yin, Hao, Yu Qian, J. Riley Edwards i Kaijun Zhu. "Investigation of Relationship between Train Speed and Bolted Rail Joint Fatigue Life using Finite Element Analysis". Transportation Research Record: Journal of the Transportation Research Board 2672, nr 10 (1.07.2018): 85–95. http://dx.doi.org/10.1177/0361198118784382.
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Reducing the allowable operating speed or imposing temporary speed restrictions are common practices to prevent further damage to rail track when defects are detected related to certain track components. However, the speeds chosen for restricted operation are typically based on past experience without considering the magnitude of the impact load around the rail joints. Due to the discontinuity of geometry and track stiffness at the bolted rail joints, an impact load always exists. Thus, slower speeds may not necessarily reduce the stresses at the critical locations around the rail joint area to a safe level. Previously, the relationship between speed and the impact load around the rail joints has not been thoroughly investigated. Recent research performed at the University of Illinois at Urbana-Champaign (UIUC) has focused on investigating the rail response to load at the joint area. A finite element model (FEM) with the capability of simulating a moving wheel load has been developed to better understand the stress propagation at the joint area under different loading scenarios and track structures. This study investigated the relationship between train speed and impact load and corresponding stress propagation around the rail joints to better understand the effectiveness of speed restrictions for bolted joint track. Preliminary results from this study indicate that the contact force at the wheel–rail interface would not change monotonically with the changing train speed. In other words, when train speed is reduced, the maximum contact force at the wheel–rail interface may not necessarily reduce commensurately.
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Seo, Jung Won, Hyun Mu Hur, Sung Tae Kwon, Jae Boong Choi i Young Jin Kim. "Effects of Residual Stress and Traction Force on the Contact Fatigue Life of Railway Wheels". Key Engineering Materials 326-328 (grudzień 2006): 1067–70. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.1067.
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Damage often occurs on the surface of railway wheels due to wheel-rail contact fatigue. Since the wheel failure can cause derailment causing the loss of life and property, it should be removed prior to the wheel failure. The effect of surface removal on contact fatigue life has been investigated by many researchers, however, the effects of residual stress and traction force have not been reported yet. The railway wheel reserves the initial residual stress due to the manufacturing process, and this residual stress is changed by the thermal stress induced by braking. Also, the traction force is usually applied along with residual stress on wheels of locomotive and electric motor vehicle. In this study, the effect of surface removal on the contact fatigue life for a railway wheel has been evaluated by applying the rolling contact fatigue test. Also, the effect of traction force and change of residual stress on the contact fatigue life has been estimated by applying finite element analysis. It is found that the residual stress is a dominant factor determining the surface removal depth as far as the traction coefficient is less than 0.15. If the traction coefficient is greater than 0.2, however, the surface removal depth is observed to be independent on the residual stress.
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Sirata, G. G., H. G. Lemu, K. Waclawiak i Y. D. Jelila. "Study of rail-wheel contact problem by analytical and numerical approaches". IOP Conference Series: Materials Science and Engineering 1201, nr 1 (1.11.2021): 012035. http://dx.doi.org/10.1088/1757-899x/1201/1/012035.
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Abstract This study presents the rail wheel contact problems under normal and tangential categories. Both analytical and numerical approaches were used for modelling, where the analytical approach assumed elliptical contact patches based on the Hertz theory. In the numerical approach, 3D finite element models were used to investigate non-elliptical contact patches. The only elastic material model was considered in the case of Hertz theory. However, in the case of finite element analysis, both elastic and elastoplastic material models were used to simulate the material's behavior under the applied load. The elastoplastic material model was used to determine the amount of stress at which the plastic deformation starts, which enables determining the rail wheel's critical load. The commercial software ABAQUS was employed for 3D modeling and contact stress analysis. The study shows maximum stress at 3 mm from the rail wheel contact surface when the maximum load of 85 kN is applied. This initiates the cracks in the subsurface and causes the portion of the rail wheel to break off in the form of spalling after a certain time.
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Axinte, Tiberiu. "Hertz Contact Problem between Wheel and Rail". Advanced Materials Research 837 (listopad 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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Watanabe, Tsutomu, Keiichi Goto, Kodai Matsuoka i Shintaro Minoura. "Validation of a dynamic wheel load factor and the influence of various track irregularities on the dynamic response of prestressed concrete sleepers". Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, nr 10 (9.12.2019): 1275–84. http://dx.doi.org/10.1177/0954409719891655.
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Prestressed concrete sleepers are generally designed taking into account the influence of the dynamic wheel load. In Japan, the dynamic wheel load factor of 2.0 has been typically used for the serviceability limit state since the 1950s. However, there are few examples that have proved its validity. In this study, field measurement tests and three-dimensional numerical analysis were conducted for prestressed concrete sleepers laid on a straight section of a railway track with continuously welded rails. According to the results of the field tests, the measured dynamic wheel load factor was less than the conventionally used dynamic wheel load factor of 2.0, and the bending moments exceeding the full prestress condition, i.e. the compressive stress on all sections, were generated in some cases. Furthermore, even with the prestressed concrete sleepers of the same type laid continuously, the bending moment was increased more than three times due to the support conditions of the prestressed concrete sleepers and the rail roughness. Results of the numerical analyses also revealed that the bending moment was increased more than two times because of the hanging (unsupported) sleepers, and the tensile stress of the prestressed concrete sleeper exceeded 3 N/mm2 when the rail roughness was approximately 2 mm or more. Based on this investigation, the validity of the dynamic wheel load factor of 2.0 was proved.
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Wen, Zefeng, Lei Wu, Wei Li, Xuesong Jin i Minhao Zhu. "Three-dimensional elastic–plastic stress analysis of wheel–rail rolling contact". Wear 271, nr 1-2 (maj 2011): 426–36. http://dx.doi.org/10.1016/j.wear.2010.10.001.
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Genshu, Tong, i Xuan Zejun. "Revisiting the bearing stresses in webs of crane runway girders under wheel loads". Advances in Structural Engineering 21, nr 12 (20.02.2018): 1792–801. http://dx.doi.org/10.1177/1369433218755520.
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This article revisited the problem of local bearing stress in webs of I-section girders supporting overhead cranes. Finite element analysis was carried out to determine the equivalent bearing length. It was found that the moment of inertia of the rail and the web thickness of the girder are the two predominant factors. The equivalent bearing lengths by the finite element analysis were found to be significantly smaller than that predicted by the formula in various codes. Analysis revealed that the differences come from the shear deformation in the rail and the load position on the rail. Closed-form solutions for a Timoshenko’s beam on a semi-infinite plane subjected to a concentrated or distributed load were presented in which the Fourier transform is used. After the shear deformation was considered and a widened load distribution length on the centroid axis of the rail, which considered the load dispersion in an angle of 35°–40° from the top of the rail to the centroid axis, are adopted in the Fourier transform solution, the analytical results are in good agreement with finite element analysis. Formulas of equivalent bearing lengths for two types of rails used in China are recommended for practical use.
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Akeel, Norie, Zainuddin Sajuri, Ahmad Kamal Ariffin i Mohamed M. Abdulrazzaq. "Three Dimensional Simulations on Stress Distribution and Fatigue Damage Life of Wheel/Rail Contact Region". Advanced Materials Research 284-286 (lipiec 2011): 1262–65. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.1262.
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This paper discusses the effect of different loading analysis on crack initiation life of wheel/rail in the contact region. A simulated three dimensional (3D) elastoplastic model of a wheel/rail contact is modelled using the fine mesh technique in the contact region by using Finite Element Method FEM code ANSYS 11.0 software. Different loads of approximately 70, 80, 90, 100, 110, 120, 130 and 140 KN were applied to the wheel tread during the running surface of the railhead to simulate stress distribution (Von Mises) and a life prediction of the crack initiation. Stress analysis is performed and the fatigue damage to the railhead surface is calculated numerically by using a multi-axial fatigue life of crack initiation model. Results obtained from previous researches are compared with this research.
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Ranjha, Sagheer Abbas, Peter J. Mutton i Ajay Kapoor. "Fatigue Analysis of the Rail Underhead Radius under High Axle Load Conditions". Advanced Materials Research 891-892 (marzec 2014): 1181–87. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.1181.
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An evaluation of the potential risk of fatigue damage at the rail underhead radius (UHR) due to the occurrence of a short duration tensile stress peak, as a wheel passes over, has been examined. The tensile stress peak is mainly due to the localised bending of the rail head-on-web and its magnitude is associated with the contact position, lateral and vertical forces and rail head wear (HW). The stresses at the underhead radius have been explored using the finite element method (FEM). The Dang Van (DV) criterion, implemented as a customised computer programme, was used to identify the fatigue damage at the UHR. Fatigue behaviour under heavy haul conditions was compared for heat-treated low alloy, euctectoid and hypereutectoid rail grades in order to predict allowable rail head wear limits.
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Thadsoongnoen, Kotchaporn, Anat Hasap, Nitikorn Noraphaiphipaksa i Chaosuan Kanchanomai. "Numerical Investigation of Residual Stress Formation Mechanisms in Flash-Butt Welded Rail". Metals 13, nr 8 (28.07.2023): 1359. http://dx.doi.org/10.3390/met13081359.
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For the construction of long and continuous railway lines as well as the replacement of defected rails, rails are joined using flash-butt welding. Under various localized temperatures and thermo-mechanical stresses, a residual stress can develop in the flash-butt welded joint. The residual stress can affect the performance and reliability of the welded rail, particularly in terms of progressive structural damage caused by repeated wheel load. In the present work, the mechanisms of residual stress formation in a flash-butt welded rail and the influence of upsetting force (including its temperature range and magnitude) were investigated using the thermal elastic–plastic finite element analysis. The formation mechanisms of residual stress involved the changes in thermal expansion coefficient, strain, and elastic modulus of the welded joint with respect to temperature. The calculated cooling temperatures and residual stresses in the flash-butt welded joint were in good agreement with the measured results. Compressive residual stresses were observed around the rail head and the rail foot (i.e., approximately −648 MPa at the rail head and −495 MPa at the rail foot), while tensile residual stresses were observed at the rail web (i.e., approximately 165 MPa). It was observed that the investigated compressive upsetting force predominantly induced plastic deformation within the welded joint, resulting in minimal alteration of stress. Consequently, the investigated ranges of upsetting temperature and upsetting forces had an insignificant impact on the formation of residual stress.
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Beneš, Libor. "ON WHEEL–RAIL CONTACT SURFACE PHENOMENA WITH STRUCTURAL CHANGES AND ‘WHITE ETCHING LAYERS’ GENERATION". TRANSPORT 27, nr 2 (26.06.2012): 196–205. http://dx.doi.org/10.3846/16484142.2012.696214.
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The main aim of this work was a study of the microstructure transformations with the residual stress formation that is induced by rolling contact friction and adhesive wore in the wheel–rail system. Several small railsurface samples, we term them as the ‘chips’, and a piece of wheel sample were chosen for the analyses of the surface changes on the wheel–rail surface. A multitude of different experiments were carried out in order to analyse the microstructure changes at the surface and the near-surface region of the material samples and, thus, to contribute to the understanding of the complex wheel–rail rolling contact phenomena – and its degradation mechanisms. The formation of nano-structured martensite and carbides on the rail and wheel surface causes the extremely high microhardness valuees and the strong corrosion resistance of the so called White Etching Layers (WEL).
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Yang, Rongshan, Shihao Cao, Weixin Kang, Jiali Li i Xiaoyu Jiang. "Mechanism Analysis of Spalling Defect on Rail Surface under Rolling Contact Conditions". Mathematical Problems in Engineering 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/7012710.
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Under the wheel/rail contact loading conditions, the microcracks on the rail surface propagate, leading to spalling defect or rail fracture and threatening the travelling safety of high-speed railway directly. In order to analyze the mechanism of the crack propagation on the rail surface, the calculation model of the wheel/rail contact fatigue was established, and the variation of the stress intensity factor at the crack tip when the crack length was increased from 0.1 mm to 2 mm was obtained. Based on the mixed-mode fracture criterion and Paris growth theory, the mechanism of the crack propagation on the rail surface was analyzed. The results show that when the microcrack grows to macrocrack, the mode of the fatigue crack on the rail surface is mixed including sliding mode and open mode. With the increase of the crack length, the stress intensity factor KI increases first and then decreases gradually, and the relative dangerous location of the open-mode crack moves from the inner edge of the contact area to the outer edge, while the factor KII is increasing during the whole propagation process, and the relative dangerous location of the sliding-mode crack remains unchanged basically. The main failure mode of crack is open during the initial stage and then transforms into sliding mode with the crack length increasing. The crack tends to propagate upward and leads to spalling defect when the crack length is between 0.3 and 0.5 mm. This propagation path is basically identical with the spalling path of the service rail. The research results will provide a basis for improving the antifatigue performance of rail and establishing the grinding procedure.
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Gao, Yuan, Ping Wang, Yibin Liu, Jingmang Xu, Zhiguo Dong i Kai Wang. "Investigation on Wheel-Rail Contact and Damage Behavior in a Flange Bearing Frog with Explicit Finite Element Method". Mathematical Problems in Engineering 2019 (14.12.2019): 1–17. http://dx.doi.org/10.1155/2019/1209352.
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Flange bearing frogs are designed to provide continuous rolling surfaces for trains traveling on the through line, but the interaction between wheel and rail in a diverging line is more complex than that for a common crossing, especially including flange bearing mode and multipoint contact during the transition. The wheel load will be transited from tread to flange and back to tread, which will intensify the wheel-rail interaction. In this paper, a numerical procedure is presented for the analysis of wheel-rail rolling contact behavior and damage prediction for the flange bearing frog. The three-dimensional explicit finite element (FE) model of a wheel passing the flange bearing frog is established to obtain the dynamic wheel-rail interaction in both the facing and the trailing move. The evolution of contact forces, the distribution of adhesion-slip regions, and shear surface stress and microslip at the contact patch are revealed. Then, the competition relationship between RCF (rolling contact fatigue) and wear of a flange bearing frog is analyzed. The results of numerical simulations can contribute to an understanding of the mechanism of the transient rolling contact behavior and provide guidance in design optimization for flange bearing frogs.
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ZHAO, Xin. "Analysis of thermal-elastic stress of wheel-rail in rolling-sliding contact". Chinese Journal of Mechanical Engineering (English Edition) 20, nr 03 (2007): 18. http://dx.doi.org/10.3901/cjme.2007.03.018.
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Yang, Liuqing, Ming Hu, Deming Zhao, Jing Yang i Xun Zhou. "Thermo-mechanical analysis of train wheel-rail contact using a novel finite-element model". Industrial Lubrication and Tribology 72, nr 5 (10.02.2020): 687–93. http://dx.doi.org/10.1108/ilt-07-2019-0298.
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Purpose The purpose of this paper is to develop a novel method for analyzing wheel-rail (W-R) contact using thermo-mechanical measurements and study the effects of heating on the characteristics of W-R contact under different creepages. Design/methodology/approach This study developed an implicit-explicit finite element (FE) model which could solve both partial slip and full sliding problems by setting different angular velocities on the wheels. Based on the model, four material types under six different creepages were simulated. Findings The results showed that frictional heating significantly affected the residual stress distribution under large creepage conditions. As creepage increased, the temperature of the wheel tread and rail head rose and the peak value was located at the trailing edge of the contact patch. Originality/value The proposed FE model could reduce computational time and thus cost to about one-third of the amount commonly found in previous literature. Compared to other studies, these results are in good agreement and offer a reasonable alternative method for analyzing W-R contact under various conditions. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0298