A matrix coupled model for vehicle-slab track-subgrade interactions at 3-D space

In this work, a matrix-coupled model for vehicle-track-subgrade interactions is complied with novel methodologies, where the vehicle, the track structures and the subgrade have all been considered as sub-components of an entire system, and their interactions are simultaneously deliberated and solved by mathematical matrix formulations. The system excitations are originated from the wheel/rail interactions by track geometries instead of moving loads, most importantly, the wheel/rail displacement complementarity and force equilibrium are satisfied in matrix characterizations, and accordingly arbitrary time steps can be implemented with a guarantee of computational stability. By introducing cyclic calculation method, infinite length calculation is achieved in this finite element model. For elaborating the accurateness, efficiency and stability of this model, numerical examples are extensively conducted. It is shown that the dynamic results such as the wheel-rail forces, subgrade stress and its attenuation pattern obtained by this model agree well with those derived by classical methods; track geometrical status possess significant influence on system vibrations, with the deterioration of track geometries, all system responses will be inevitably increased by different extent; and this model provides possibility of analyzing the performance of track-subgrade systems subject to moving vehicles from aspects of system dynamics.