Extraordinary acoustic absorption induced by hybrid resonance and electrical energy generation from sound by hybrid resonant metasurface

A sound absorbing metamaterial comprising

• an acoustic impedance-matched surface configured to minimize reflection from an incident acoustic wave, the surface comprising:
• an elastic or flexible membrane;
• a relatively solid surface provided as a reflective surface and positioned behind the membrane and separated by a predetermined distance from the elastic or flexible membrane and forming a fluid space between the membrane and the solid surface;
• a substantially rigid mass mounted on the membrane, whereby the elastic membrane with the mass establish a plurality of eigenfrequencies;
• and
• an electric generator responsive to movement of the membrane.

A sound absorbing metamaterial comprising

• means for providing an acoustic impedance-matched surface configured to minimize reflection from an incident acoustic wave, the surface comprising:
• elastic or flexible membrane;
• reflective means, positioned behind the membrane means and separated from the membrane means by a predetermined distance and forming a fluid space between the membrane and the solid surface;
• and
• a substantially rigid mass mounted on the membrane;
• means, comprising the membrane and rigid mass, to establish a plurality of eigenfrequencies for resonance.