Research on vibration control and nonlinear dynamic behavior of railway vehicle systems based on nonlinear energy sinks

During long-term service, railway vehicles are prone to abnormal vibrations of the car body and bogie frames. To suppress vibrations in both the car body and bogie frames simultaneously, this paper proposes the distributed installation of nonlinear energy sinks (NES) on railway vehicles, with multiple NES units installed on the car body and bogie frames. First, a nine-degree-of-freedom coupled dynamic model of the railway vehicle and NES is established. An approximate analytical solution of the model is derived using the harmonic balance method and verified by numerical simulations. The effects of the NES mass, cubic stiffness, and damping on the amplitude–frequency response curves of the car body and bogie frames are analyzed. Finally, the influences of these NES parameters on the nonlinear dynamic behavior of the model are investigated. The effects of the NES parameters on the system response are analyzed from multiple perspectives, including time–history curves, phase trajectories, and Poincaré maps. The results indicate that the distributed installation of NES units can effectively suppress vibrations of the car body and bogie frames. Moreover, reasonable optimization of the mass, damping, and cubic stiffness of each NES can further reduce structural vibrations, while avoiding adverse effects induced by bifurcation and chaotic responses in the system. This study provides guidance for the parameter design of NES and offers fundamental theoretical support for their engineering application, which is of great significance for vibration mitigation in railway vehicles.