Abstract: To effectively address the impact of rail transit vibrations on the environment, we proposed a quasi-zero stiffness locally resonant metamaterial (QZS-LRM) vibration isolation structure composed of steel and thermoplastic polyurethane rubber. Finite element software was utilized to demonstrate the quasi-zero stiffness characteristics of the structure in both horizontal and vertical directions through preload method. We analyzed the mechanism of band gap generation, discussed the influence of preload on the band gap, and validated the accuracy of the band gap range using the transmission spectrum. Additionally, we compared the vibration isolation performance of the horizontal and vertical arrangements and verified the vibration isolation effect of QZS-LRM using measured high-speed rail vibration data. The results indicate that a larger preload leads to a lower band gap initiation frequency and an increased bandwidth. The transmission spectrum confirms the band gap range, and the vibration isolation effect of the horizontal arrangement is significantly superior to that of the vertical arrangement. Based on the measured acceleration data from the Shanghai-Kunming high-speed railway, frequency domain and time domain analyses reveal that the maximum acceleration amplitude attenuation exceeds 90% in both cases, confirming the effective vibration isolation performance of QZS-LRM.

Key words: quasi zero stiffness, local resonance, metamaterials, low bandwidth vibration reduction and isolation, surface wave