METASURFACE WAVE BARRIERS FOR AMBIENT VIBRATION MITIGATION

To mitigate the ambient vibration induced by trains, a novel metasurface wave barrier is designed in this work by periodically arranging the underground in-filled pipes. Systematic dispersion analysis, transmission simulation and experimental study are conducted. The main conclusions are obtained as follows: the surface wave attenuation zone (SWAZ) is opened due to the strong interaction between vertically resonance of in-filled pipes with surface waves. The position and width of SWAZ are mainly affected by the local resonance characteristics of in-filled pipes, which can be designed by adjusting the material and geometrical parameters. Significant surface wave attenuation is observed within the SWAZ, and the performance is strengthened with the increase of rows. Besides, this novel wave barrier is suitable for not only active isolation but also passive isolation. Experimental results confirm the excellent vibration mitigation within SWAZ of metasurface wave barriers. The average insertion loss within SWAZ is 9.8 dB. The main working mechanism is the mode conversion from surface waves to shear bulk waves. The introduction of certain degrees of construction errors (≤10%) doesn’t affect the existence of SWAZs. High efficiency and robustness of vibration mitigation of metasurface wave barriers are verified by numerical and experimental studies. By inputting the measured train-induced acceleration into the numerical model in the time domain, the feasibility of metasurface wave barriers to ambient vibration mitigation is preliminarily verified. Due to the high efficiency, robust performance and low cost of metasurface wave barrier, it has great potential for ambient vibration mitigation induced by trains.