Dynamic Analysis of Pitch Plane Railway Vehicle-Track Interactions Due to Single and Multiple Wheel Flats

Abstract

The dynamic impact forces due to the wheel defect such as a flat is a main concern for a heavy freight train operating at high speed. The present investigation employs a pitch plane vehicle model coupled with a comprehensive three-layer track system model to study the impact force generated in the wheel-rail interface due to the presence of wheel flats. The wheel-rail contact is modeled using nonlinear Hertzian contact theory. Responses in terms of wheel-rail impact load and forces transmitted to bearings, pad and ballast are evaluated in an attempt to identify desirable design and operating factors. Wheel-rail impact loads due to the presence of multiple flats either in single or different wheels in-phase or out-of-phase conditions are evaluated and analyzed. A detailed parametric study is carried out that includes the variations in selected vehicle, track, operational as well as flat parameters. The results show that the effect of multiple flats is insignificant if they are more than 45° apart. The impact due to single wheel flat can be larger than in-phase flats at each wheel due to the presence of pitch dynamics. The parametric study shows that other than speed, depth and length of the flats are most sensitive parameters, and there exists a critical length at each flat depth that leads to the largest impact load.

A Two‐Step Composite Time Integration Scheme for Vehicle‐Track Interaction Analysis considering Contact Separation

“…Vibrations of the vehicle are transmitted to the track through wheel-rail contact, resulting in the excitation of track vibrations, which is in reverse act on the vehicle [1]. Meanwhile, the wheel flat [2] and track irregularities [3] are input to the coupled system via the wheel-rail force which significantly amplifies the dynamic interaction and generally displays nonlinear properties. e computational cost is greatly increased.…”

Dynamic response of a locomotive with AC electric drives to changes in friction conditions

“…The simplest model proposed to reveal the overall dynamics of a locomotive is a quarter rail vehicle model; it is preferred in many studies due to its simplicity and ease of application. 2,3 A Newtonian/Lagrangian full locomotive model for locomotive dynamic analysis has also been built by applying basic Newtonian principles or the Lagrangian method. 4,5 However, these are either limited by modelling simplicity, particularly for the traction and control dynamics, or simulation time.…”