A model of a discretely supported railway track based on a 2.5D finite element approach

Abstract

The dynamic properties of a railway track are important for both the generation of rolling noise and the development of rail corrugation. A conventional track consists of long rails mounted periodically on transverse sleepers and supported in ballast. In order to improve the predictions of the noise and vibration of the track, a model of a discretely supported track is proposed based on the so-called 2.5 dimensional (2.5D) finite element approach, which is used to model an infinite free rail. This is coupled to a finite number of sleepers, by means of an array of springs representing each rail pad, using a receptance coupling method. The sleepers are represented by flexible beams, supported on an elastic foundation. Results are presented in terms of the point mobility and track decay rate and these are compared with the corresponding field measurements for two tracks, one with soft rail pads and one with stiff rail pads. Very good agreement is found between the predictions and the measurement results, especially for the track with soft rail pads. The flexible sleeper model is shown to give improved results compared with a rigid mass model, especially for the track with stiff rail pads.

Differences between Euler-Bernoulli and Timoshenko beam formulations for calculating the effects of moving loads on a periodically supported beam

“…The mobility of the discretely supported rail is calculated using the method described in Section 2.2 in which a finite number of supports are added to the bottom of the rail and the full system is solved using a receptance coupling method [39]. For the FE model, at each support point three springs of approximately equal stiffness are included across the width of the rail foot.…”

“…The aim of this paper is to investigate the differences in the parametric excitation occurring for a load moving along a periodic track using models based on Euler-Bernoulli beams and Timoshenko beams. The reasons for the discrepancies found are addressed by comparing the results with those obtained using a model of a discretely supported rail based on a 2.5D finite element (FE) model [39] which is used as a reference. The influence of the moving load speed on the parametric excitation is also explored.…”

Using a 2.5D boundary element model to predict the sound distribution on train external surfaces due to rolling noise

“…Besides, Zhang. et al [10] proposed a model of a discretely supported track based on the waveguide finite element (2.5D FE) approach in order to improve the predictions of the vibration of the track. Very good agreement was found between their predictions and the measurement results, especially for the track with soft rail pads.…”

Changing the dynamic characteristics of the track to reduce noise emissions - numerical study

“…The dynamic properties of the railway track are crucial in noise forecasting, and the appropriate track dynamics model should take into account interactions between different components [13]. The rail can be treated as an infinitely long beam in which the propagation of mechanical waves takes place.…”