A Practical Wheel-Rail Interaction Element for Modeling Vehicle-Track-Bridge Systems

A novel practical element is presented for simulating the vertical wheel-rail interaction (WRI) of vehicle-track-bridge (VTB) coupling systems. The WRI is time- and location-varying, which makes the simulation of the VTB system complicated. The new element simulates the WRI using a location dependent internal resisting force, which enables the finite element (FE) model of the VTB system to remain unchanged in analysis. This element is capable of simulating the nonlinear WRI, the rail irregularity and the ‘additional’ displacement of the rail. The ‘additional’ displacement is the extra displacement caused by the WRI besides that interpolated from the element nodal displacements, which is usually ignored by existing models, but may be non-negligible in some cases. The WRI element is implemented into a general FE software framework, OpenSees, and verified by the dynamic analysis of a simply-supported beam subjected to a moving sprung mass. Furthermore, a realistic VTB system with a moving four-wheel vehicle is investigated to evaluate the cases where the additional displacement and nonlinear WRI should be considered. Finally, using another realistic VTB system subjected to rail irregularities and earthquakes, the effects of rail irregularity and earthquake on the dynamic responses of the WRI system are studied and compared.