Spectral analysis of train-rail-bridge coupling system considering frequency-dependent stiffness of rail fastening systems

A rubber rail-pad is typically inserted between the rail and the sleeper to attenuate wheel/rail vibrations for conventional train-rail-bridge (TRB) system. For mathematical modeling, a rail-fastener with rubber pad is simplified as a spring-dashpot unit, whose spring stiffness is related to the exciting frequency of external loads. To exhibit such characteristics of rail-pads on TRB dynamics, based on dynamic flexibility method, two computational models of constant/frequency-dependent stiffness (FDS) are considered for comparison. Numerical studies reveal that the FDS model provides a strengthening benefit for the wheel rail vibration, from which the shifted dominant frequencies in spectral response are observed.