Low frequency energy scavenging using sub-wave length scale acousto-elastic metamaterial

Abstract

This letter presents the possibility of energy scavenging (ES) utilizing the physics of acousto-elastic metamaterial (AEMM) at low frequencies ( < ∼3 KHz), maximum power in the micro Watts (∼35μW) range can be generated, whereas, recently reported phononic crystal based metamaterials harvested only nano Watt (∼30nW) power against 10KΩ resistive load. Efficient energy scavengers at low acoustic frequencies are almost absent due to large required size relevant to the acoustic wavelength. Here we report sub wave length scale energy scavengers utilizing the coupled physics of local, structural and matrix resonances. Upon validation of the argument through analytical, numerical and experimental studies, a multi-frequency energy scavenger (ES) with multi-cell model is designed with varying geometrical properties capable of scavenging energy (power output from ∼10μW - ∼90μW) between 0.2 KHz and 1.5 KHz acoustic frequencies.