Vibration reduction and dynamic response analysis of urban railway steel-spring floating slabs under periodic track irregularities

Abstract

Periodic Track Irregularities (PTI) are a significant and sensitive source of vehicle dynamic response. However, previous studies have mainly focused on how to address periodic irregularities themselves, with limited research on the dynamic response and vibration reduction effects of PTI excitation on conventional tracks and Steel Spring Floating Slab Tracks (SSFST). In order to better reveal the vibration reduction effect of SSFST under PTI excitation and the influence of SSFST parameters on vibration reduction, the PTI spectra of actual operating tracks were collected, and a vehicle track system dynamic model including subway vehicles and track structures was established. The vibration reduction mechanisms of SSFST and the effects of related parameters on vibration reduction under real PTI excitation were analyzed. The results show that: In simulation models and real experiment, the primary frequency of 2 Hz, indicated by modal analysis, is the characteristic fault frequency resulting from the coupled mode of bogie hunting and car body yaw; The lateral acceleration amplitude of the floating slab track model is reduced by 57.4% compared to the conventional track, demonstrating significant suppression of periodic irregularity excitation and effective vibration reduction for wheelsets, frames, and car bodies by absorbing excitation energy; The vibration reduction of the floating slab track is affected by fastener and isolator stiffness and damping, with fasteners having a greater influence. At 80 MN/m stiffness and 10–30 kN·s/m damping, the 2 Hz vibration amplitude drops by 56%–68%.