Computational analysis of phononic crystal vibration isolators via FEM coupled with the acoustic black hole effect to attenuate railway-induced vibration

The problem of ambient vibration caused by urban rail transit continues to be serious, but it has not been satisfactorily resolved. This study investigates the structure of a novel phononic crystal vibration isolator (NPCVI) in which the low-frequency and multi-modal features of the acoustic black hole (ABH) structure are used to create coupling vibration between the ABH rubber and steel resonator. The bandgap is widened and the vibration isolation capability of the phononic crystal vibration isolator is optimized. By establishing a finite element model, the multi-bandgap behavior of the NPCVI is discussed, and its vibration isolation capability is demonstrated via studies of the force transmission spectrum. The energy distribution in the finite element model reveals the nature of multi-bandgap formation. Finally, a train–floating slab track–tunnel coupled dynamic model is established to investigate the vibration isolation capability of the NPCVI under the excitation of various track irregularities. The results demonstrate that, under various train speeds, the NPCVI exhibits a superior vibration isolation capability as compared to that of a steel-spring vibration isolator.