Abstract
A 3D dynamic model of a high-speed train coupled with a flexible ballast track is developed and is presented in this study. In this model, each vehicle is modeled as a 42 degrees of freedom multi-body system, which takes into consideration the nonlinear dynamic characteristics of the suspensions. A detailed inter-vehicle connection model including nonlinear couplers and inter-vehicle dampers, and the linear tight-lock vestibule diaphragm is established to simulate the effect of the end connections of neighboring vehicles on dynamic behavior. The track is modeled as a traditional three-layer discrete elastic support model. The rails are assumed to be Timoshenko beams supported by discrete sleepers. Each sleeper is treated as an Euler beam and the ballast bed is replaced by equivalent rigid ballast bodies. The reliability of the present model is then validated through a detailed numerical simulation comparison with the commercial software SIMPACK, with the effect of the track flexibility on the train/track interaction being analyzed simultaneously. The proposed model is finally applied to investigate the difference between dynamic performances obtained using the entire-train/track model (TTM) and the single-vehicle/track model (VTM). Several key dynamic performances, including vibration frequency response, ride comfort, and curving performance, calculated by the two types of dynamic models are compared and discussed. The numerical results show that there is a significant difference between the dynamic behaviors obtained by VTM and TTM, and that inter-vehicle connections have an important influence on the dynamic behavior of high-speed vehicles.
Highlights
High-speed railways are developing rapidly in many countries around the world
A 3D dynamic model of a nonlinear high-speed train coupled with a flexible ballast track is put forward
The advantages of this model are: (1) the mutual influence of the adjacent vehicles on the dynamic behavior of high-speed vehicles and the track is considered; (2) it is possible to carry out fast dynamics calculations on a long train running on an infinitely long flexible track
Summary
High-speed railways are developing rapidly in many countries around the world. The mileage of commercial high-speed railway in China exceeds 6000 km. The classical vehicle dynamics study using a simplified rigid track model cannot solve the dynamic problems caused by the failure of a track component and other severe conditions, such as the running safety of railway vehicles passing over unsupported tracks, broken rails, and buckled tracks These models, cannot characterize the dynamical behavior of track components or the ground vibration induced by high-speed trains in operation. When high-speed trains run in complex operating environments, such as a derailment occurring due to strong cross-winds, earthquakes, or serious track buckling, the mutual influence between the adjacent vehicles on the system’s dynamic behavior should not be neglected in a dynamical behavior analysis (Evans and Berg, 2009; Zhang, 2009; Jin et al, 2013) In these environments, any VTM cannot characterize the behavior of the vehicle and track accurately and reliably.
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