Assessing track geometry quality based on wavelength spectra and track–vehicle dynamic interaction
ABSTRACT This paper presents a study of assessing track geometry quality (longitudinal level and alignment) by the use of dynamic track–vehicle simulations and wavelength spectra analysis. Two simulation models are developed: one is based on the software package GENSYS, which provides realistic simulations of the nonlinear dynamic behaviour of a vehicle running on real track, and the other one is based on a newly developed linear track–vehicle model, which is suitable for effectively calculating wheel–rail forces for very long track sections. The linear model, first proposed in 11.
Berggren , E. G. , Li , M. X.D. and Spännar , J. 7th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems (CM2006) . September 24–27 , Brisbane, Australia. A new approach to the analysis and presentation of vertical track geometry quality and rail roughness with focus on train–track interaction and wavelength conten , View all references 22.
Li , M. X.D. , Berggren , E. G. and Berg , M. Proceedings of IHHA Special Technical Session . June 11–13 , Kiruna, Sweden. Assessment of vertical track geometry quality based on simulations of dynamic track–vehicle interaction , View all references to assess vertical track geometry quality (longitudinal level), is extended in the present paper to simulate lateral track–vehicle dynamic interaction and, thus, to assess lateral track geometry quality (alignment) as well. Numerical results are presented to compare the simulation results with online measurement and to demonstrate the possibilities of enhancing track quality assessment and maintenance by simulations of track–vehicle interaction.
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ABSTRACT: A numerical model to predict train-induced vibrations is presented. The dynamic computation considers mutual interactions in vehicle/track coupled systems by means of a finite and discrete elements method. The rail defects and the case of out-of-round wheels are considered. The dynamic interaction between the wheel-sets and the rail is accomplished by using the non-linear Hertzian model with hysteresis damping. A sensitivity analysis is done to evaluate the variables affecting more the maintenance costs. The rail-sleeper contact is assumed extended to an area-defined contact zone, rather than a single-point assumption which fits better real case studies. Experimental validations show how prediction fits well experimental data.Vehicle System Dynamics 09/2013; 51(9):1342-1362. · 0.87 Impact Factor
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ABSTRACT: Testing of the running characteristics of railway vehicles requires well-defined boundary conditions like track geometry quality. Test sections with the same track geometry quality must lead to the same dynamic vehicle response (VR) forces. The state-of-the-art methods do not fulfil this important requirement for a track quality definition. Our proposed method for track geometry assessment considers the vehicle/track interaction. ‘Representative’ transfer functions are used for the prediction of the vehicle reaction. Therefore, the results show a significant enhancement of the correlation between the track assessment quantities and the VR forces.Vehicle System Dynamics 12/2010; 48:157-173. · 0.87 Impact Factor
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ABSTRACT: This paper studies the use of second-order derivatives of track irregularities (longitudinal level, LL) for assessing vertical track geometry quality. Both a single-degree-of-freedom and a three-DOF vehicle–track model are investigated in order to explain theoretically why from the aspect of vehicle–track dynamic interaction it is relevant to consider not only the amplitudes of LL but also their second-order derivatives (LL2). Simulation results are then presented to demonstrate that dynamic vertical track forces are more correlated with the second-order derivatives (LL2) than to the amplitudes (LL) themselves. A comparison of the power spectral density (PSD) spectra for typical track reveals that it is more convenient to use the PSD spectra for the second-order derivatives than for the amplitudes, as the curves for the second-order derivatives are flat within the short wavelength range. Finally, the practical use of derivatives within the maintenance management system in order to achieve improved assessment of track geometry quality is also discussed.Vehicle System Dynamics 01/2012; 50:389-401. · 0.87 Impact Factor