Nonlinear Model of an Embedded Rail System for the Simulation of Train-Track Dynamic Interaction and the Analysis of Vibration Transmission

Nonlinearities in the track system are important and sometimes necessary to be taken into consideration in the study of the train-track interaction and its relevant issues, especially when resilient materials are employed. In the present work, static and dynamic characterisations of an embedded rail system (ERS) were performed through laboratory tests. The dynamic behaviour of the ERS varies considerably with the test conditions. The collected data are then used to develop a nonlinear rheological model of unit length of the ERS. The identified model is in good agreement with the experimental data and reproduces effectively the dynamic behaviour of the ERS. The identified nonlinear model is then integrated with a 2D track model for the simulation of train-track dynamic interaction. Simulations of rail deflection time history corresponding to a train passage are performed employing both linear and nonlinear track models. The results demonstrate that the nonlinear model leads to a significantly different track response with respect to the one obtained with the linear track model and thus suggest that the nonlinear track behaviour needs to be carefully accounted for in train-track dynamic interaction simulation and that the nonlinear rheological model can be an efficient tool to achieve this objective.