We investigate the interaction of guided surface acoustic modes (GSAMs) in unconsolidated granular media with a metasurface, consisting of an array of vertical oscillators. We experimentally observe the hybridization of the lowest-order GSAM at the metasurface resonance, and note the absence of mode delocalization found in homogeneous media. Our numerical studies reveal how the stiffness gradient induced by gravity in granular media causes a down-conversion of all the higher-order GSAMs, which preserves the acoustic energy confinement. We anticipate these findings to have implications in the design of seismic-wave protection devices in stratified soils.
Hybridization of Guided Surface Acoustic Modes in Unconsolidated Granular Media by a Resonant Metasurface / Palermo, Antonio; Krödel, Sebastian; Matlack, Kathryn H.; Zaccherini, Rachele; Dertimanis, Vasilis K.; Chatzi, Eleni N.; Marzani, Alessandro*; Daraio, Chiara. - In: PHYSICAL REVIEW APPLIED. - ISSN 2331-7019. - ELETTRONICO. - 9:5(2018), pp. 054026.1-054026.7. [10.1103/PhysRevApplied.9.054026]
Hybridization of Guided Surface Acoustic Modes in Unconsolidated Granular Media by a Resonant Metasurface
Palermo, Antonio;ZACCHERINI, RACHELE;Marzani, Alessandro
;
2018
Abstract
We investigate the interaction of guided surface acoustic modes (GSAMs) in unconsolidated granular media with a metasurface, consisting of an array of vertical oscillators. We experimentally observe the hybridization of the lowest-order GSAM at the metasurface resonance, and note the absence of mode delocalization found in homogeneous media. Our numerical studies reveal how the stiffness gradient induced by gravity in granular media causes a down-conversion of all the higher-order GSAMs, which preserves the acoustic energy confinement. We anticipate these findings to have implications in the design of seismic-wave protection devices in stratified soils.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
