Study on effect of wheel polygonal wear on high-speed vehicle-track-subgrade vertical interactions

Wheel polygonal wear, as a form of wheel surface damage, is of great concern and potential threat to the deterioration and safety of railway systems. The experimentally measured polygonal wear can be treated as a superimposed wave with different harmonic orders, phases and wave depths, accordingly various frequency components are included. Most of the previous research is focused on vehicle-track vibrations caused by wheel polygon, while its influence on subgrade performance is rarely referred. With this consideration, a vertical model for vehicle-track-subgrade dynamic interactions is established by the Green function method with high accurateness and efficiency. In the numerical analysis, three types of excitations are considered, i.e., the measured polygon, the harmonic polygon and the track random irregularity. Numerical results show that the short wavelength excitation originated from the measured wheel polygon induce high-frequency wheel-rail interactions, which intensify the wheel and rail vibrations and have additional effects on the vibration modes of the displacement and stress curves of the subgrade surface; with the increased polygon order and wave depth, the wheel-rail vertical forces, wheel unloading rates, fastener forces and rail accelerations are significantly exacerbated; the vertical displacement and stress of the subgrade system are mainly affected by the lower orders of wheel polygon.