Abstract
With increases in train speed and traffic density, problems due to wheel polygons and those caused by wheel–rail impacts will increase accordingly, which will affect train operational safety and passenger ride comfort. This paper investigates the effects of polygonal wheels on the dynamic performance of the track in a high-speed railway system. The wheel–rail interaction forces caused by wheel polygons are determined using a dynamic vehicle–track model, and the results are entered into a slab track finite element model. The influence of the harmonic order and out-of-roundness (OOR) amplitude of wheel polygons on the transient dynamic characteristics of the track(von Mises equivalent stress, displacement, and acceleration) is examined under high-speed conditions. The results indicate that the vibration acceleration and von Mises equivalent stress of the rail increase in proportion to the harmonic order and the OOR amplitude and velocity of a polygonized wheel. The vibration displacement of the rail first increases and then decreases with a change in the harmonic order, and reaches a maximum at the ninth order. The dynamic responses of the concrete slab layer, cement-asphalt layer, and support layer increase linearly with the harmonic order and amplitude of wheel polygons and decrease from top to bottom. Through a combination of numerical simulations and real-time monitoring of rail vibrations, this study provides guidance on potential sensor locations to identify polygonized wheels before they fail.
Highlights
The phenomenon of train wheel polygons—that is, wheels with a certain degree of out-of-roundness (OOR)—is a well-known problem for high-speed railways [1].The term “wheel polygon” refers to periodic radial deviations from the ideal round shape of the circumference of the wheel
The goal of this paper is to study the influence of the wheel polygon order, OOR amplitude, and train speed on the dynamic performance of a slab track
The track dynamics as a result of the passage of a polygonal wheel at high speeds were determined using the finite element model described in Section 2 considering the three relevant parameters: Harmonic order, OOR amplitude, and running speed
Summary
The phenomenon of train wheel polygons—that is, wheels with a certain degree of out-of-roundness (OOR)—is a well-known problem for high-speed railways [1].The term “wheel polygon” refers to periodic radial deviations from the ideal round shape of the circumference of the wheel. The technical term “harmonic order” refers to a sinusoidal radial deformation of the circumference with a specific period. Polygonal wheels produce a number of problems. At speeds above 200km/h, this phenomenon will cause considerable vibrations, which are transmitted to the train compartments via the wheels and from the rails to the track components, resulting in the deterioration of infrastructure, noise disturbance, and an increase in maintenance costs [2]
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