Wheel wear prediction on a high-speed train in China

Tao G., Ren D., Wang L., Wen Z., Jin X.

The objective of this study is to develop a new online model for wheel wear that takes into account the track flexibility. The proposed model consists of two parts that interact with each other, namely, (a) a locomotive/track coupled dynamics model considering the track flexibility, which is validated by field measurement results, and (b) a model for the wear estimation. The wheel wear prediction model can be employed in online solutions rather than in post-processing. The effect of including the track flexibility on the wear estimation is investigated by comparing the results with those obtained for a rigid track. Moreover, the effect of the wheel profile updating strategy on the wheel wear is also examined. The simulation results indicate that the track flexibility cannot be neglected for the wheel wear prediction. The wear predicted with the rigid track model is generally larger than that predicted with the flexible track model. The strategy of maintaining unchanged wheel profiles during the dynamic simulation coincides with the online updating strategy in terms of the predicted wear.

Luo R., Shi H., Teng W., Song C.

The aim of this paper is to accurately predict the evolution of wheel profile wear and related vehicle dynamics for high-speed trains by considering the stochastic wheel/rail interactions, which experience quite variants with time and along long distant high-speed lines in China. These variants include the rail profiles, track geometries, track irregularities and interface characteristics associated with each segment of track. Mathematic normal distribution is introduced to rationally describe these stochastic parameters. The Archard wear model and FASTSIM algorithm are employed to determine the wear within a contact patch of the wheel, and a strategy based on the travel distance of wheel is used in the profile updating procedure. Referring to previous works, a nonlinear multibody vehicle system model is built and its accuracy was validated by lab tests. In the numerical simulation, three methods of stochastic matching of parameters in wheel/rail interactions are performed, including all constant parameters, only stochastic rail profiles, and both stochastic rail profiles and stochastic track parameters. Comparative studies show that there are good agreements in the wear evaluation of wheel profile between the simulated and measured results, as well as the behavior evaluation of vehicle dynamics in a total travel distance of 300,000 km. It is essential, therefore, to consider the stochastic matchings of parameters in the wheel/rail interaction for predicting the wheel profile wear and vehicle dynamics evolution of high-speed trains.

Hossein-Nia S., Sichani M.S., Stichel S., Casanueva C.

In this article, a wheel life prediction model considering wear and rolling contact fatigue (RCF) is developed and applied to a heavy-haul locomotive. For wear calculations, a methodology based on ...

Casanueva C., Enblom R., Stichel S., Berg M.

The renewal costs for wheels and rails are a substantial part of the costs for rolling stock operators and infrastructure managers all over the world. The causes for reprofiling or grinding are, in most cases, related to the following: (1) wheel or rail profiles with unacceptable wear, (2) appearance of rolling contact fatigue cracks in the surface, and (3) wheel flats caused by locking wheels during braking. The first two causes are related to the dynamic behavior of the vehicle–track system, and can be predicted using multibody simulations. However, there are several limitations that restrain the usefulness of these prediction techniques, such as simulation time constraints, necessary simplifications, and lack of experimental data that lead to educated assumptions. In this paper, we take the end-user perspective in order to show whether the latest developments in wheel–rail damage prediction can be integrated in a simplified framework, and subsequently used by the different stakeholders for an improved management of the different assets involved in the operation of rail vehicles.

Sh. Sichani M., Enblom R., Berg M.

In most rail vehicle dynamics simulation packages, tangential solution of the wheel–rail contact is gained by means of Kalker's FASTSIM algorithm. While 5–25% error is expected for creep force estimation, the errors of shear stress distribution, needed for wheel–rail damage analysis, may rise above 30% due to the parabolic traction bound. Therefore, a novel algorithm named FaStrip is proposed as an alternative to FASTSIM. It is based on the strip theory which extends the two-dimensional rolling contact solution to three-dimensional contacts. To form FaStrip, the original strip theory is amended to obtain accurate estimations for any contact ellipse size and it is combined by a numerical algorithm to handle spin. The comparison between the two algorithms shows that using FaStrip improves the accuracy of the estimated shear stress distribution and the creep force estimation in all studied cases. In combined lateral creepage and spin cases, for instance, the error in force estimation reduces from 18% to less than 2%. The estimation of the slip velocities in the slip zone, needed for wear analysis, is also studied. Since FaStrip is as fast as FASTSIM, it can be an alternative for tangential solution of the wheel–rail contact in simulation packages.

Gan F., Dai H., Gao H., Chi M.

A calculation method for contact bandwidth and its change rate is developed. The method can be used to quantify the wheel–rail contact point geometry relationship and evaluate the quality of type S1002CN wheel tread after undergoing a tread reprofiling process, as well as to analyze a trend of the wheel–rail contact state and the tread wear state. Firstly, the wheel tread shapes of type S1002CN are measured with increasing train operation distance covered in one wheel tread reprofiling cycle. Secondly, wheel–rail indexes, such as cumulative wear, equivalent conicity, contact bandwidth and its change rate, are calculated in order to obtain the change trend. Finally, a diagram of contact points on the wheel surface can be drawn over the whole tread reprofiling cycle. Based on the calculation results, the contact bandwidth and its change rate are more sensitive than the equivalent conicity, and a more comprehensive assessment for the worn shape of the wheel tread, the running stability of the vehicle, the wheel–rail contact state and the tread wear state has been established. The method has been applied to research on the wear of wheel treads of high speed train, and the results show that the calculation and evaluation methods are reasonable and viable.

Han P., Zhang W.

Wheel wear is an important factor that could affect the normal service of the high-speed trains. Wheel wear status plays a significant role in evaluating the safety and reliability in the operation of high-speed trains. At first, the line-tracking measurement was conducted and the wear profile data under different operation mileages was analyzed to get the characteristics of wheel wear. Then, polynomial fitting based on the least squares method was conducted twice to get a numerical wear prediction method in which the wear location on the profile and operation mileage was regarded as the variables. The accuracy of the prediction model was verified through the comparison of geometry characteristics and wheel/rail interaction. Utilizing the predicted and measured profiles, we found the consistent calculation results of vehicle ability, riding index and the characteristic curves of the lateral and vertical accelerations of key components. As a consequence, this binary model is an accurate approach for the application of wheel profiles prediction.

Sh. Sichani M., Enblom R., Berg M.

An approximate analytical method is proposed for calculating the contact patch and pressure distribution in the wheel-rail interface. The deformation of the surfaces in contact is approximated using the separation between them. This makes it possible to estimate the contact patch analytically. The contact pressure distribution in the rolling direction is assumed to be elliptic with its maximum calculated by applying Hertz' solution locally. The results are identical to Hertz's for elliptic cases. In non-elliptic cases good agreement is achieved in comparison to the more accurate but computationally expensive Kalker's variational method (CONTACT code). Compared to simplified non-elliptic contact methods based on virtual penetration, the calculated contact patch and pressure distribution are markedly improved. The computational cost of the proposed method is significantly lower than the more detailed methods, making it worthwhile to be applied to rolling contact in rail vehicle dynamics simulation. Such fast and accurate estimation of contact patch and pressure paves the way for on-line modelling of damage phenomena in dynamics simulation packages.

Cui D., Wang H., Li L., Jin X.

The high maintenance cost of high-speed wheels due to wear and rolling contact fatigue is a major problem in the commercial operation of high-speed trains in China. In order to understand the wear behavior of high-speed wheels and its influence on the motion stability of high-speed trains, the worn profiles and the work-hardening of the wheels of the CRH3 high-speed trains that operate on the Wuhan–Guangzhou line were monitored in different periods during service; in particular, the influence of hollow wear of the wheel on the lateral acceleration of the bearing-box was investigated in detail. A new wheel profile design method was suggested to reduce the hollow wear by seeking an optimization match of the wheel profiles, the vehicle’s suspension systems, and the wear behavior of wheels in service. The feasibility of the method was verified by numerical simulation using the operation conditions of CRH3 high-speed trains on the Wuhan–Guangzhou line. A new wheel profile was designed using this method. The wheel/rail contact performance and the vehicle’s dynamic behavior resulting from the designed new wheel were investigated in detail and compared with those of the original wheel. The wear behavior of the designed new wheel profile was predicted based on wear data measured on the original wheel. The results show that compared with the original wheel profile, the designed new wheel profile can improve the wheel/rail contact state, reduce the contact stress level, and lower the friction power of wheel and rail. The extent of hollow wear on the new wheel is significantly decreased and the vehicle has improved dynamic behavior when wheelsets with the designed new profile are used. Thus, the period before re-profiling is required can be effectively extended.

Ignesti M., Innocenti A., Marini L., Meli E., Rindi A.

The modelling and the reduction of wear due to wheel–rail interaction is a fundamental aspect in the railway field, mainly correlated to safety, maintenance interventions and costs. In this work, the authors present two innovative wheel profiles, specifically designed with the aim of improving the wear and stability behaviour of the standard ORE S1002 wheel profile matched with the UIC60 rail profile canted at 1/20 rad, which represents the wheel–rail combination adopted in the Italian railway line. The two wheel profiles, conventionally named CD1 and DR2, have been developed by the authors in collaboration with Trenitalia S.p.A. The CD1 profile has been designed with the purpose of spreading the contact points in the flange zone on a larger area in order to reduce wear phenomena and having a constant equivalent conicity for small lateral displacements of the wheelset with respect to the centred position in the track. The DR2 wheel profile is instead designed to guarantee the same kinematic characteristics of the matching formed by ORE S1002 wheel profile and UIC60 rail profile with laying angle αp equal to 1/40 rad, widely common in European railways and characterised by good performances in both wear and kinematic behaviour. The evolution of wheel profiles due to wear has been evaluated through a wear model developed and validated by the authors in previous works. The wear model comprises two mutually interactive units: a vehicle model for the dynamic simulations and a model for the wear assessment. The whole model is based on a discrete process: each discrete step consists in one dynamic simulation and one profile update by means of the wear model while, within the discrete step, the profiles are supposed to be constant. The choice of an appropriate step is crucial in terms of precision and computational effort: the particular strategy adopted in the current work has been chosen for its capacity in representing the nonlinear wear evolution and for the low computational time required. In the present research, the investigated trainset is the passenger vehicle ALSTOM ALn 501 ‘Minuetto’, which is usually equipped with the standard ORE S1002 wheel profile in Italian railways. The entire model has been simulated on a virtual track specifically developed to represent a statistical description of the whole Italian line. The data necessary to build the virtual track and the vehicle model were provided by Trenitalia S.p.A. and Rete Ferroviaria Italiana. The CD1 and DR2 wheel profiles, matched to the UIC60 rail with cant 1/20 rad, have shown a good behaviour in terms of wear resistance if compared with the old ORE S1002 wheel profile, consequently assuring a more uniform distribution of the removed material and a prolongation of the mean time between two subsequent re-profiling interventions.

Ignesti M., Malvezzi M., Marini L., Meli E., Rindi A.

a b s t r a c t The prediction of the wear at the wheel-rail interface is a fundamental problem in the railway field, mainly correlated to the planning of maintenance interventions, vehicle stability and the possibility of researching specific strategies for the wheel and rail profile optimization. In this work the Authors present a model specifically developed for the evaluation of the wheel and rail profile evolution due to wear, whose layout is made up of two mutually interactive but separate units: a vehicle model for the dynamic analysis and a model for the wear estimation. The first one is made up of two parts that interact online during the dynamic simulations: a 3D multibody model of the railway vehicle implemented in Simpack Rail (a commercial software for the analysis of multibody systems) and an innovative 3D global contact model (developed by the Authors in previous works) for the detection of the contact points between wheel and rail and for the calculation of the forces in the contact patches (implemented in C/C++environment). The wear model, implemented in the Matlab environment, is mainly based on experimental relationships found in literature between the removed material and the energy dissipated by friction at the contact. It starts from the outputs of the dynamic simulations (position of contact points, contact forces and global creepages) and calculates the pressures inside the contact patches through a local contact model (FASTSIM algorithm); then the material removed due to wear is evaluated and the worn profiles of wheel and rail are obtained. This approach allows the evaluation of both the quantity of removed material and its distribution along the wheel and rail profiles in order to analyze the development of the profiles shape during their lifetime. The whole model is based on a discrete process: each discrete step consists in one dynamic simulation and one profile update by means of the wear model while, within the discrete step, the profiles are supposed to be constant. The choice of an appropriate step is fundamental in terms of precision and computational load. Moreover the different time scales characterizing the wheel and rail wear evolution require the development of a suitable strategy for the profile update: the strategy proposed by the Authors is based both on the total distance traveled by the considered vehicle and on the total tonnage burden on the track. The entire model has been developed and validated in collaboration with Trenitalia S.p.A. and Rete Ferroviaria Italiana (RFI), which have provided the technical documentation and the experimental results relating to some tests performed with the vehicle DMU Aln 501 Minuetto on the Aosta-Pre Saint Didier line.

Li X., Jin X., Wen Z., Cui D., Zhang W.

The important published papers on railway wheel profile wear in the past are reviewed and have been highlighted. A wheel profile wear prediction methodology is developed to improve an extant model and used to predict the wear of the wheels of railway vehicle operating on sharp curved tracks. The methodology includes the coupling dynamics of railway vehicle and track, the three-dimensional contact geometry analysis of wheel/rail, Kalker's non-Hertzian rolling contact theory, and Archard wear model. The normal loads, creepages and lateral displacements of the wheel/rail are first obtained through the coupling dynamics analysis of the vehicle/track. Then the wheel/rail contact geometry calculation is carried out to get the normal gap between the undeformed wheel/rail. Based on the attained parameters, the wheel–rail rolling contact is calculated using the modified Kalker's non-Hertzian theory, and the normal stress, slip and contact areas are obtained. Afterwards, the Archard wear model is used to calculate the wear depth on the wheel tread, and the two means, which are called the smoothing spline and the Super-smother, are used to smooth the wear distribution curve and the updated wheel profile due to the accumulated wear after a number of passages. A numerical example is presented to verify the present effective methodology. The obtained numerical results are reasonable, and indicate that the numerically reproduced wear phenomena of the wheels of the vehicle are consistent with those occurred at railway sites.

Jin Y., Ishida M., Namura A.

The experimental research on the wears of wheel and rail has been carried out using a large rolling-sliding contact test machine with the actual profiles of wheel and rail. Primarily, the effects of axle load, the angle of attack, rail hardness and lubrication on wear behaviors of wheel flange and rail gauge corner have been particularly focused in research. Based on those experimental results, the Archard wear coefficients of Japanese track were calculated under various conditions. A wear prediction model of rail profile taking into consideration contact stress, slip ratio at contact patch and material hardness was established based on the experimental results and the wheel–rail contact analyses. The prediction results were compared with the measured values of the actual rail and the effectiveness of wear prediction methodology was verified for the actual railway system.

Sun Y.Q., Cole C., Boyd P.

A numerical method using VAMPIRE for modelling the dynamic performance of a wagon passing through a turnout is presented with a special focus on wheel–rail wear. The objective is to investigate the potential benefit for operational strategies with respect to minimising wheel–rail wear. The simulations show that the travel speed significantly affects the wheel–rail wear at turnouts and that due to vehicle–track dynamics an optimal passing speed will exist that will minimise wear.

Pombo J., Ambrósio J., Pereira M., Lewis R., Dwyer-Joyce R., Ariaudo C., Kuka N.

When compared with road traffic, railway transportation is safer, more comfortable, less polluting and presents less energy consumption per passenger/km. When compared with the airplane, high speed trains are able to compete for short and medium distances, with the advantage of having better energy efficiency and causing less pollution. However, to maintain the operational performance of railway vehicles, it is necessary that the quality of the wheel–rail contact is controlled, which requires, among others, a good understanding of the wear mechanisms of the wheels and the consequences of their changing profile on vehicle dynamics. In this work, a computational tool that is able to predict the evolution of the wheel profiles for a given railway system, as a function of the distance run, is presented. The strategy adopted consists of a commercial multibody software to study the railway dynamic problem and a purpose-built code for managing its pre and post-processing data in order to compute the wear. Three alternative wear functions are implemented to compute the amount of worn material on the railway wheels. The computational tool is applied here to a realistic operational scenario in order to demonstrate its capabilities on wear prediction. Special attention is given to the comparison of the results obtained with the different wear functions implemented in this work and to the global and local contact models used in such formulations.

Li H., Tan T., Stichel S., Yao Y.

Augusto de Paula Pacheco P., Valente Lopes M., Correa P.H., Bosso N., Magelli M., Zampieri N., Antunes dos Santos A.

Multibody simulations of train dynamics commonly employ generic short tracks to validate and observe the behaviour of wagons in certain conditions. However, for proper wheel wear analysis, the entire railway track should be modelled, increasing computational cost and time to obtain worn profiles and wear parameters. The major novelty of this work is the description of a reproducible algorithm-based methodology to obtain a statistically representative shorter equivalent railway track for wear simulations. The proposed methodology includes combining a real measured track with multibody dynamic simulation. To verify the approach, a case study was conducted on a 505 km-long railway in Brazil. Additionally, two distinct vehicles were employed: a European wagon with a standard gauge and a Brazilian wagon with a meter gauge. The shorter equivalent tracks were compared in terms of worn area and wear depth to the initial track, and the generated tracks were cross-compared between vehicles to verify the robustness of the method. It is observed that wear simulations can be performed more efficiently and effectively, reducing the computational time by at least 94%, while still obtaining accurate results, given that the final equivalent tracks were 18.59 times shorter for the Brazilian model and 22.45 times shorter for the European model comparing to the real track, with the maximum deviation being 6.55% in flange depth and with a maximum root mean-square error (RMSE) of 871 nm.

Lu B., Song Y., Liu Z., Wang X., Zhang Q., Lu Y.

Xie Y., Cai W., Li Y., Yang J., Liang S., Chi M.

The wheel-rail contact geometry strongly affects the dynamic running behavior of a railway vehicle, so it is a key factor for its operational safety. Although wear in the wheel-rail contact is generally inevitable, a particular problem is the occurrence of nonuniformly distributed wear, which changes the wheel profile and thereby often leads to a deterioration of the vehicle's running behavior. Therefore, the restoration of the wheel profile, known as reprofiling, is an important maintenance action for ensuring operational safety. The exact restoration of the original wheel profile, however, often requires the removal of a high volume of material, which can drastically shorten the service life of the wheel. An incomplete restoration of the wheel profile, which requires the removal of less material, extends the wheel's service life and is therefore also known as "economic reprofiling". Nevertheless, an incompletely restored wheel profile, too, must still fulfill the same requirements as the original profile with respect to the vehicle's running behavior and thereby to its operational safety. While previous work mainly dealt with the impact of flange wear, the present study focuses on the wheel tread frequent contact area (WTFCA). This study presents a long-term wheel wear prediction model for a high-speed train and proposes a design method for the wheel profile in the WTFCA for economic reprofiling. After optimizing the key factors, the utilization of the wheel profile for economic reprofiling can comprehensively consider the dynamic performance, wear behavior, and economic performance of the vehicle, which can be applied to guide the maintenance of the wheel profile.

Qi Y., Dai H., Sang H., Hou M.

As the operation speed of China’s high-speed trains continues to increase, a variety of complex wheel wear problems continue to emerge. Many line tests show that the differential wheel wear of the motor car and trailer car is obvious. The aim of this paper is to explore the differential wear mechanism of motor cars and trailers and their effect on dynamic performance. Firstly, this paper established a high-speed train model, which consists of two motor cars and two trailers. Then the causes of differential wear of the high-speed train from the perspective of wheel-rail contact and wheel wear were analyzed, and the Jendel wear model was used for wheel wear prediction. The wear model was verified through measured wheel wear data. Lastly, the dynamic performance of the differential wear of the high-speed train was analyzed. The results showed that the different distribution of the adhesive sliding zone in the contact patch, the different wheel-rail normal force, and tangential forces are the reasons for the differential wear. The established dynamic model and wear model can effectively predict the differential wear of the motor cars and trailer, and the maximum wear depths of the motor car and the trailer wheel were 0.886 mm and 0.721 mm. This verified the validity of the simulation model. When wheel differential wear occurs, the overall dynamic performance of the trailer is superior to that of the motor cars.

Wang H., Li Y., Men T.

Zeng Y., Chen B., Chi Q., Zhang X.

Wear caused by wheel–rail contact forces is inevitable during vehicle operation, which has an important impact on the security and stability of train operation. Therefore, it is of great significance to study wheel wear patterns and optimize re-profiling strategies to extend service life. Based on the wheel wear data of three-axle bogie locomotives, this paper proposes a data-driven hybrid wheel wear model and optimization schemes of the re-profiling strategy. The wear model consists of a wheel flange thickness wear model, a wheel diameter wear model, and a re-profiling ratio coefficient model. Then, utilizing the above models, the optimization of the re-profiling strategy for different axle position wheels is raised, and the optimization of the complete vehicle re-profiling strategy is presented by considering the wheel diameter difference. Finally, a wheel data-driven analysis platform was developed to enable the management and utilization of wheel maintenance data. Analysis of extensive maintenance data indicates that the guide wheels wear the fastest, approximately 22.2% higher than the middle wheels, which wear the slowest. The re-profiling ratio coefficient model indicates that the ratio coefficient increases as the wheel flange thickness before re-profiling increases. Simulations demonstrate a longer expected wheel life with a flange thickness between 28 and 32.5 mm. Compared to measured values, the optimization strategy reduces complete vehicle re-profiling by 21.5%. Through the initial implementation at CRRC Dalian Locomotive Ltd, it has become evident that this methodology offers a viable solution to enhance the service longevity of locomotive wheels.

Wang P., Yang X., Tao G., Wen Z.

A reliable model for predicting wheel wear that considers the interaction between an abrasive block and a wheel as well as the contact between the wheel and rail is developed. First, a wheel wear prediction model that integrates vehicle system dynamics and the Archard wear model for wheel–rail interactions is developed. The wheel wear prediction procedure is validated using measured wheel profiles without the influence of abrasive blocks. Second, a new wheel wear prediction model that integrates the previously validated wheel wear prediction model, a finite element method, and a modified Archard wear model for abrasive block–wheel interactions is developed. The new method for predicting wheel wear is validated using the measured data with acting abrasive blocks. The results show that the tread wear rate due to wheel–rail contact is approximately 0.057 mm/104 km and that the tread wear rate due to abrasive block–wheel and wheel–rail contact is approximately 0.070 mm/104 km at a continuous air pressure of 3.0 bar.

Chen C., Zhu F., Xu Z., Xie Q., Lo S.M., Tsui K.L., Li L.

Liang Y., Wei L., Zeng J., Luo R., Wang Q.

The hunting stability is an important issue for vehicle systems that determines the maximum operating speeds of the high-speed trains. In this paper, the research background for the three abnormal vibration phenomena of the high-speed trains caused by the hunting stability problems, including the “VIP Chair Shaking,” “Bogie Alarm,” and “Carbody Sway” problems, are introduced. Firstly, the reason why the vehicle hunting motion loses its stability is investigated from the viewpoint of wheel/rail contact relation. Then, a modified wheel profile is recommended in order to solve or relieve the stability problem, in which the slope at the flange root for the original wheel profile is decreased and the slope at the wheel tread end is increased. Furthermore, the numerical model for a high-speed passenger car is established to verify the dynamic performance of the modified wheel profile. Finally, the dynamic test for the vehicle equipped with the modified wheels is carried out using full-scale roller test rig to validate the theoretical analysis. It can be seen from simulations and validation tests that the wheel/rail contact relation and the dynamic performance including the hunting stability and ride comfort for the high-speed vehicle with the modified wheel are improved significantly compared with the original wheel.

Men T., Liu B., Li Y., Lin Y., Zhang Y.

Miao G., Luo R., Shi H.

Wheel-rail geometric parameters are crucial for determining wheel wear in high-speed trains. Under the action of a wheel-rail load, both the wheel and rail suffer elastic deformation, which affects the wheel-rail contact relationship and further influences the wheel profile and its evolution. In this study, a field test was conducted on a high-speed train operating at 250 km/h, and the worn wheel profiles and wear curves were continuously measured for one reprofiling cycle. Subsequently, a vehicle dynamics model is built using a wheel wear prediction model based on the integrated USFD wear algorithm. In this model, the finite element model of the wheel-rail contact is considered. The wheel-rail geometric parameters are obtained by determining their elastic deformation through the finite element method, which considers the effect of three parameters: the track gauge, back-to-back space of the wheelset, and rail cant. After considering the wheel-rail elastic deformation, the track gauge decreases from 1435 to 1434.5 mm, the back-to-back space varies from 1353 to 1352.3 mm, and the rail cant changes from 1:40 to approximately 1:37. Finally, the simulation and experimental results are compared, revealing that the wheel-rail elastic deformation has a significant impact on the wheel wear after the vehicle travels 150,000 km. The wear depth and wheel-rail equivalent conicity after considering the elastic deformation are closer to the measured results.

Liu S., He Q., Fu W., Feng Q.

Cai W., Chi M., Wu X., Huang H.

High-order wheel polygonal wear is a significant concern on China’s high-speed trains; thus far, no satisfactory solution to prevent polygonal wear has been provided. In this study, a simplified vehicle-track coupling dynamic model was established, and the frequency response functions (FRF) of the wheel-rail force were obtained under multiple wheelsets conditions. After integrating a wheel-rail wear model, the rail localized bending modes (RLBM) were recognized as critical factors for the amplitude-frequency and phase-frequency properties of the wheel-rail force response and further gave rise to the growth of high-order polygonal wear. Consequently, rail dynamic vibration absorbers (DVA) were introduced into the vehicle-track coupling dynamic model as single-degree-of-freedom rigid bodies arranged at equal intervals along the track. The influencing mechanism of rail DVAs on the rail localized bending resonance, as well as the resulting polygonal wear, was investigated in detail. Results suggested that the rail localized bending resonance could be easily suppressed when the tuned frequency of the rail DVAs approaches the resonance frequency. However, due to newly generated resonance peaks, the polygonal wear was observed to persist. The phase-frequency property of the wheel-rail force response is a determining contributor to the growth trend of polygonal wear; therefore, the rail-tuned DVA should be designed to force the phase lag out of the positive growth region, namely 90° to 270°. Our results indicated that a DVA with a tuned frequency of 450 Hz could effectively slow the development of high-order polygonal wear on China’s high-speed trains, and the shorter installation interval of rail DVAs improves the suppression effect. This study proposed a phase-based design rule for rail DVAs to achieve wheel-rail periodic wear mitigation.

He C., Zou G., Gan Y., Ye R., Zhai Y., Liu J.

This study presents the rolling contact fatigue (RCF) mechanism and damage behavior of the motor wheel and trailer wheel of a high-speed EMU operating over 1.73 million kilometers in a wind and sand environment in Northwest China. The results indicate that the profile hardness of the wheel decreases with increasing distance from the surface and finally stabilizes. Within a certain distance from the surface, the hardness of the flange root changes sharply. The surface of the tread hardens, the hardness value increases, and the variation law is similar to that of the plastic deformation of the profile. The wheel treads of the motor and trailer suffer more serious damage, such as cracks, spalling pits, dents and pitting on the surface. The profile damage is mainly characterized by long and thin layered cracks and branch cracks. Cracks located at the root of the flange and outside of the nominal circle tend to propagate toward the inside of the flange and form branch cracks and delamination cracks, which may cause multiple cracks to penetrate each other to form spalling.