Railway ground vibrations induced by wheel and rail singular defects

Abstract

Railway local irregularities are a growing source of ground-borne vibration and can cause negative environmental impacts, particularly in urban areas. Therefore, this paper analyses the effect of railway track singular defects (discontinuities) on ground vibration generation and propagation. A vehicle/track/soil numerical railway model is presented, capable of accurately predicting vibration levels. The prediction model is composed of a multibody vehicle model, a flexible track model and a finite/infinite element soil model. Firstly, analysis is undertaken to assess the ability of wheel/rail contact models to accurately simulate the force generation at the wheel/rail contact, in the presence of a singular defect. It is found that, although linear contact models are sufficient for modelling ground vibration on smooth tracks, when singular defects are present higher accuracy wheel/rail models are required. Furthermore, it is found that the variation in wheel/rail force during the singular defect contact depends on the track flexibility, and thus requires a fully coupled vehicle/track/foundation model. Next, a parametric study of ground vibrations generated by singular rail and wheel defects is undertaken. Six shapes of discontinuity are modelled, representing various defect types such as transition zones, switches, crossings, rail joints and wheel flats. The vehicle is modelled as an AM96 train set and it is found that ground vibration levels are highly sensitive to defect height, length and shape.

The Effect of Track Unevenness Correlation on Railway Induced Ground Vibration

“…(5) due to the unit amplitude rail irregularity at all contact points can be calculated using Eq. (3) with . The elements of the receptance matrix in Eq.…”

“…and thus the complex amplitude of the vertical profile is given as (3) If both rails and both wheels of each wheelset ( ) are considered separately, the coupling at the contact point is expressed by the relation (4) where is the complex receptance of the wheel, is the is the complex receptance of the rail and is the wheel-rail contact force. Inserting these two equations into Eq.…”

“…On the wheels, short wavelength unevenness is again caused by wear whereas discrete wavelengths up to about 3 m are present due to out-of-roundness. Additionally, dynamic forces are generated as impacts as the wheels traverse switches and crossings or badly maintained rail joints [2][3].…”

Dynamic Response of Wheel-Rail Interaction at Rail Weld in High-Speed Railway

“…In addition, the stiffness coefficient of the normal contact spring used in the traditional vehicletrack coupling dynamics model is generally derived from the Hertz theory based on the static hypothesis, which contains some differences when dynamic interaction between wheel and rail is taken into account [19]. Moreover, as vehicle speed increases, wheel-rail high-frequency vibration inspired by short wavelength irregularity cannot be ignored [20]. To represent this characteristic, wheel and rail should be modelled as solid element but not beam as in traditional vehicle-track coupling dynamics model [1,[7][8][9][10].…”

Far-Field Earthquake Responses of Overhead Line Equipment (OHLE) Structure Considering Soil-Structure Interaction

“…Therefore, the dynamic behaviors of cantilever mast structure and its monitoring system are needed to take into account during train operation and the occurrence of extreme environmental events. Although the effects of ground borne vibration generated by passing train on cantilever mast have been studied (Kurzeil, 1979;Madshus et al, 1996;Jonsson, 2000;Kouroussis et al, 2013Kouroussis et al, , 2014Kouroussis et al, , 2015Vogiatzis and Mouzakis, 2017), the effects of earthquake have not been introduced.…”