On the modelling of normal wheel-rail contact for high-frequency vehicle-track dynamics analyses

A transient wheel-rail rolling contact (RC) model and a vehicle-track coupled dynamics (CD) model are separately developed for a Hertzian contact in elasticity to calculate normal wheel-rail interactions at high frequencies. Short-wave irregularities with a wavelength of 20 similar to 400 mm are considered for a speed of 50 similar to 500 km/h. Results of 180 cases show that contact forces predicted by the CD model are significantly different from those by the RC model, suggesting that ignored or greatly simplified structural and wheel-rail flexibilities, transient effects, finite contact patch, etc. in the CD approach, play important roles in high-frequency interactions. Using the RC predictions as reference, a modified non-linear Hertzian spring is developed to improve the accuracy of the CD model. Such a modification provides references for determination of contact spring and contact filter effect at high frequencies, even though not applicable in a direct way.

Automated summary

A transient wheel-rail rolling contact model and a vehicle-track coupled dynamics model were developed to calculate normal wheel-rail interactions at high frequencies in elasticity. The results of 180 cases showed significant differences in contact forces predicted by the CD model compared to the RC model, indicating the important role of ignored structural and wheel-rail flexibilities in high-frequency interactions. A modified non-linear Hertzian spring was developed to improve the accuracy of the CD model with reference to the RC predictions, providing insights for determination of contact spring and contact filter effect at high frequencies.