The number of operating high-speed trains in China is around 2800 today and 179,200 wheels are under maintenance in one reprofiling period. To help researchers to understand the evolution of the wheel profile and improve the reprofiling strategy of the wheels, this study predicts the development of wheel profiles on a high-speed train as function of mileage and compare simulated worn wheel profiles with measured ones. The methodology includes transient multi-body dynamic simulation, wheel-rail contact calculation and wear calculation with Archard's model. Calibrated by analysing measurements of worn S1002CN profiles and performing parameters sensitivity study in the wear model, the model is then used to predict the development of a recently designed wheel profile, called S1002CN-RF. The simulation results for S1002CN and S1002CN-RF show that the predicted wheel profiles coincide with the measured ones. Wear prediction of another high-speed wheel profile (LMA) validates that the vehicle performance with respect to wear could be further improved compared to using S1002CN or S1002CN-RF. Finally, the influence of track alignment and operating speed is investigated. The wear increases with the speed increasing up to 300 km/h, but stays almost constant with a further speed increase from 300 to 400 km/h.

The contact model between wheel and rail is significant for predicting wear of the wheel profile with help of multi-body dynamics simulation. Among the contact models, Hertz’s theory and Fastsim algorithm are widely used in MBS software due to high computational efficiency and acceptable precision. But with respect to wear, the accuracy of such a contact model is insufficient, especially for predicting the wear distribution. A new non-elliptic contact model called ANALYN/FaStrip with fast calculation speed has been proposed to improve the precision for both normal and tangential solutions. This paper investigates the influence of this new contact model on the wear calculation by comparing with Hertz/Fastsim in terms of contact pressure and creep forces, and finally indicates the difference of wear depth calculated by the two contact models. The results illustrate that significant improvements can be gained by implementing ANALYN/FaStrip into the wheel wear prediction.

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.

A novel wheel-rail contact model is proposed to be implemented for multi-body dynamics simulation, in order to facilitate accurate online calculation of damage phenomena such as wear and rolling contact fatigue. The normal contact, i.e. contact patch and pressure distribution, is calculated using a fast non elliptic algorithm called ANALYN. The tangential contact, i.e. tangential stress distribution, stick-slip division and creep force calculation, is treated using an alternative to the FASTSIM algorithm that is based on a strip theory which extends the two-dimensional solution of rolling contact to three-dimensional contacts. The proposed contact model is compared to the Hertz+FASTSIM model and evaluated using the CONTACT code in terms of contact patch and stress distribution as well as creep force curves. The results show that the proposed model can significantly improve the estimation of the contact solution both in terms of creep force estimation and contact details, such as stress distribution, needed for damage predictions.

In most rail vehicle dynamics simulation packages, creep forces are estimated by means of Kalker's FASTSIM algorithm. While 5%-25% error is expected for force estimation the errors of shear stress distribution, needed for wheel/rail damage analysis, may rise above 30%. This is mainly due to the use of parabolic traction bound in FASTSIM. Thus, a novel algorithm called FaStrip is proposed as an alternative to FASTSIM. It is based on the strip theory in which elliptic traction bound is used. The comparison between the two algorithms, evaluated by CONTACT, shows that using FaStrip improves the accuracy of the estimated shear stress distribution while the creep force estimation in all studied cases is significantly improved as well. In one case, for instance, the error in force estimation reduces from 18% to less than 2%. Since FaStrip is as fast as FASTSIM, it can be an alternative for tangential solution of the wheel-rail contact in simulation packages.

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.

 Simulation of wheel and rail wear allows to predict long term profile evolution and thus, study the consequences of wheel damage in the dynamic behaviour of the vehicle, or study future maintenance requirements. Several models have been developed which try to solve the wear issue by relating the energy dissipated in the wheel-rail contact to the worn out material, from which two can be highlighted (Tg/A and Archard) which have significant differences on contact level. Even though, the prediction of long term wheel profile evolution has been validated with these two models, which means that for regular applications they seem to have an equivalent behaviour. In this work similarities and differences between the long term wear prediction methodologies are analysed, discussing their actual limitations. Then, these differences are exploited in specific operational cases to compare their wear prediction performance.

A model which can predict the length of the surface crack and crack depth in rails was developed in a previous study by the authors B. Dirks, R. Enblom, A. Ekberg, M. Berg (2015) []. In the present study, verification of this crack prediction model in combination with a wear prediction model was done against wheel measurements. For a period of 15 months, the wheels of three units of a Stockholm commuter train were measured with respect to wear and crack development for verification of the wheel life prediction tool. Vehicle-track dynamics simulations were used to calculate the forces and contact positions for the wear and crack prediction models. It can be concluded that the wear prediction model gives reasonable results, especially considering the large scatter in the wheel profile measurements. Although the wheel life prediction tool could not be verified, since the crack prediction model had to be recalibrated for the current wheel application, the results appear promising.

This paper presents a comparison of four models of rolling contact used for online contact force evaluation in rail vehicle dynamics. Until now only a few wheel-rail contact models have been used for online simulation in multibody software (MBS). Many more models exist and their behaviour has been studied offline, but a comparative study of the mutual influence between the calculation of the creep forces and the simulated vehicle dynamics seems to be missing. Such a comparison would help researchers with the assessment of accuracy and calculation time. The contact methods investigated in this paper are FASTSIM, Linder, Kik-Piotrowski and Stripes. They are compared through a coupling between an MBS for the vehicle simulation and Matlab for the contact models. This way the influence of the creep force calculation on the vehicle simulation is investigated. More specifically this study focuses on the influence of the contact model on the simulation of the hunting motion and on the curving behaviour.