Stability of a two-mass oscillator moving on a beam supported by a visco-elastic half-space

Environmental vibrations due to railway traffic are predominantly due to dynamic axle loads caused by wheel and track unevenness and impact excitation by rail joints and wheel flats. Because of its irregular character, track unevenness is commonly processed statistically and represented by its power spectral density function or its root mean square (RMS) value in one-third octave bands. This statistical description does not uniquely define the track unevenness at a given site, however, and different track unevenness profiles matching the statistical description will lead to different predictions of dynamic axle loads and resulting ground vibration. This paper presents a methodology that allows quantifying the corresponding variability in ground vibration predictions. The procedure is derived assuming the geometry of the track and soil to be homogeneous along the track. The procedure is verified by means of Monte Carlo simulations and its usefulness for assessing the mismatch between predicted and measured ground vibration is demonstrated in a case study. The results show that the response in time domain and its narrow band spectrum exhibit significant variability which is reduced when the running RMS value or the one-third octave band spectrum of the response are considered.

Section: Introductionmentioning

confidence: 99%

Quantification of uncertainty in the prediction of railway induced ground vibration due to the use of statistical track unevenness data

Lombaert

Galvín

François

et al. 2014

“…Lombaert et al [8,10] have applied the formulation presented by Metrikine et al [11], Metrikine and Popp [12], and Dieterman and Metrikine [13], to predict vibrations produced by railway traffic using a coupled two-and-half boundary element-finite element formulation in the frequency domain. In that approach the vehicle is coupled to an infinite length beam that represents the track and a half-space representing the soil.…”

mentioning

confidence: 99%

Fully three-dimensional analysis of high-speed train–track–soil-structure dynamic interaction

Galvín

Romero

Domínguez

2010

230

102

In this paper, a general and fully three dimensional multi-body-finite element-boundary element model, formulated in the time domain to predict vibrations due to train passage at the vehicle, the track and the free field, is presented. The vehicle is modelled as a multi-body system and, therefore, the quasi-static and the dynamic excitation mechanisms due to train passage can be considered. The track is modelled using finite elements. The soil is considered as a homogeneous half-space by the boundary element method. This methodology could be used to take into account local soil discontinuities, underground constructions such as underpasses, and coupling with nearby structures that break the uniformity of the geometry along the track line. The non-linear behaviour of the structures could be also considered. In the present paper, in order to test the model, vibrations induced by high-speed train passage are evaluated for a ballasted track.The quasi-static and dynamic load components are studied and the influence of the suspended mass on the vertical loads is analyzed. The numerical model is validated by comparison with experimental records from two HST lines. Finally, the dynamic behaviour of a transition zone between a ballast track and a slab track is analyzed and the obtained results from the proposed model are compared with those obtained from a model with invariant geometry with respect to the track direction.

“…Such problems occur when road or railway vehicles interact with their supporting infrastructure. In these analyses, a lot of emphasis has gone to physical phenomena occuring when the train speed approaches or exceeds the Rayleigh wave velocity in the soil [25,198,199]. This may occur for high speed trains running on tracks supported by soft soils and give rise to high vibrations and track displacements, affecting track stability and safety.…”

Section: Interaction Through a Moving Interfacementioning

confidence: 99%

Dynamics of structures coupled with elastic media—A review of numerical models and methods

Clouteau

Cottereau

Lombaert

2013

This paper reviews issues and developments in the field of structure-environment interaction problems, in which the environment is an elastic body, possibly unbounded. It covers in particular the fields of soil-structure interaction, ground-borne noise and vibration emitted by transportation systems and wave diffraction by obstacles in an elastic medium. The general setting for a linear bounded structure coupled to an unbounded linear environment through a bounded interface is first recalled, and the domain decomposition technique classically used for its description is put up. Extensions for the cases of non-linear structure and uncertain environment are then discussed. Finally, the ongoing research in the fields of unbounded interface, moving interface, and multiple interfaces are reviewed and summarized.