Modelling of periodic slab track using time-frequency hybrid Green's function method and its application to vehicle-track dynamic interaction

Abstract

Periodic slab tracks, as a type of non-ballasted track, are widely used in the high-speed railway and urban subway. Efficient and accurate dynamics modelling of the periodic slab track is a crucial issue for solving the vehicle-track dynamic interaction. In this paper, a time-frequency hybrid Green's function method (GFM) is first developed to model the dynamics of the periodic slab track, in light of the properties of the periodicity, symmetry and attenuation of the Green's functions. By combining with the classical vehicle-rail dynamics model, the simulation of the vehicle-track dynamic interaction is then performed. To improve the computational efficiency, the step-moving window strategy is introduced to characterize the vehicle moving on the infinite length track. The floating slab track, a representation of the periodic slab track, is adopted to reflect the time-spatial distribution of the Green's functions. The truncation errors caused by the presented GFM are analysed by calculating dynamic responses induced by a metro vehicle moving on the floating slab track to determine the truncation parameters. The proposed GFM-based vehicle-track dynamic interaction model is finally validated by comparing with the finite element method (FEM) and the basic dynamic characteristics of the periodic slab track are further investigated. Numerical studies show that the computational accuracy of the GFM-based model is nearly the same with the FEM-based model, but the efficiency can be greatly improved. Moreover, it is concluded that the longitudinal uneven stiffness of the periodic slab track shows a significant influence on the slab displacement and stress, while has a slight influence on the fastener force and slab acceleration.