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PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING
Edited by: B.H.V. Topping, L.F. Costa Neves and R.C. Barros
The Dynamic Design of High Speed Railway Tracks using a Combined Multibody and Finite Element Approach
S. Bruni and S. Alfi
Department of Mechanical Engineering, Politecnico di Milano, Italy
S. Bruni, S. Alfi, "The Dynamic Design of High Speed Railway Tracks using a Combined Multibody and Finite Element Approach", in B.H.V. Topping, L.F. Costa Neves, R.C. Barros, (Editors), "Proceedings of the Twelfth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 37, 2009. doi:10.4203/ccp.91.37
Keywords: train-track interaction, wheel-rail contact, slab track.
The paper proposes a mathematical model for the numerical simulation of train-track interaction, based on a multibody schematization of the train and on a finite element description of the track vibration. The model is fully three-dimensional, and accounts for the non-linearities inherent in wheel-rail contact.
By using the above mathematical model, the design of a slab track system is performed from the point of view of the vibro-acoustic performance, assessing the effectiveness of the anti-vibration measures such as the continuous support of the rail and the use of resilient material at the interface between the slab and the track foundation. The results of numerical calculations are compared with line measurements performed on a prototype slab track installed along an Italian railway line, and tested up to 200km/h, as part of the activities carried out in the FP5 research project HIPERTRACK.
The paper includes a detailed description of the mathematical model used in the research, presents the results of numerical simulations from the viewpoint of assessing different design measures on the vibro-acoustic impact of the track, and reports the main findings of the vibration measurements performed on the track demonstrator in the line.
Experimental and numerical results presented in the paper show that the floating slab track with continuous rail support is highly effective in reducing the vibration transmitted to the environment either through the soil or air borne. As far as air borne noise is concerned, the use of the continuous rail support reduces the levels of rail vibration by 3-5dBs, hence favourably affecting wheel-rail interaction. This results in the reduction of the "inherent" gap between the a slab track and a ballasted track in terms of air borne noise by 2dBs, caused by a noise reflection on the coherent surface of the slab. Since this latter effect could be avoided by the use of an additional noise absorption-anti reflection layer on top of the slabs, it can be suggested that by the adoption of these additional devices, reductions in the total noise emission levels of the order of 2-3dB with respect to a standard ballasted track could be expected from the slab track considered in this paper.
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