A three-dimensional model for train-track-bridge dynamic interactions with hypothesis of wheel-rail rigid contact

In the field of train-track-bridge interaction, there are mainly two major classifications, i.e., coupling method and uncoupling method. The uncoupling method shows advances in characterizing the nonlinear wheel-rail contacts in geometries and forces but needing to strictly satisfy solution convergence by small time step size, or iterative procedures and other alternatives needed. While for the coupling method, it possesses fairly high computational stability by satisfying geometrical compatibility and force equilibrium automatically, but there still exist large deficiencies in revealing wheel-rail contact geometries/creepages with higher efficiency and refinement, especially with consideration of wheel-rail separations. In this paper, a three-dimensional (3-D) model for train-track-bridge interaction is proposed under the fundamentals of strongly coupling strategy with innovative methodologies. Firstly a coupling matrix for track-bridge finite element system is constructed, in which a versatile method founded on energy principle is developed. Through this method, the elemental number and form of bridges can be arbitrarily chosen. Then the key matrices for coupling the train and the track-bridge system are presented in detail, especially the matrix formulations corresponding to wheel-rail separations are introduced. Through a particular examination of this newly developed train-track-bridge dynamic model, it is found out that this model shows high computational stability, accuracy and efficiency comparing to conventional solutions; besides some key parameters such as the bridge elemental length, track-bridge section length in numerical integrations can be clarified by this model conveniently. (C) 2019 Elsevier Ltd. All rights reserved.