Dynamic Models of Railway Track Taking Account of Cross-Section Deformation at High Frequency

Track dynamic behaviour is important for the prediction of the rolling noise, corrugation growth and track damage. Various models have been developed in the literature but problems still remain. On the one hand, analytical models become insufficient because of the need to include cross-section deformation at high frequencies. On the other hand, FE models are straightforward but the truncation of the infinite length is unavoidable. A new tapered plate rail model is developed in this paper. This model takes into account all the main motions required for frequencies below 7 kHz. The rail head is represented by a rectangular beam, the web by a plate of constant thickness and the foot by a plate of variable thickness. The out-of-plane and in-plane motions of the plates are approximated using cubic and linear functions, respectively, based on the relevant wave speeds. Freely propagating waves in the rail are studied by means of Hamilton’s principle. Comparing the results in terms of the dispersion relations, the tapered plate rail model shows good agreement with an FE model. Comparison with simpler beam models confirms the improvements at high frequencies due to the taper of the foot.