Modeling and Fabrication of a Multi-Axial Piezoelectric Energy Harvester Based on a Metamaterial-Inspired Structure

Due to the limited availability and high depletion rates of nonrenewable energy sources as well as environmental concerns, the scientific community is urged to explore and harness alternative, clean energy sources. In this paper, a novel piezoelectric energy harvester based on a metamaterial structure is proposed, which is capable of scavenging energy from low-frequency, multi-axial ambient vibrations. The proposed energy harvester is based on a mass-in-mass phononic crystal structure and is comprised of a spherical heavy core resonator and piezoelectric wafers, encapsulated in a cylindrical rubber matrix, and encased in a rigid cubic frame. The proposed cell behaves effectively such as a negative mass in the vicinity of its resonance frequencies and entraps the vibration energy as dynamic strain. The captured kinetic energy is then transformed to electric potential using three lead-zentrale-Teichmann wafers, optimally embedded in the cell's soft constituent. In this paper, the proposed energy harvester cell is analytically modeled, numerically simulated via COMSOL Multiphysics software, and experimentally validated using a variety of uni- and multi-axial vibration excitations.