Multiband elastic wave energy localization for highly amplified piezoelectric energy harvesting using trampoline metamaterials

In this study, we investigate high-performance piezoelectric energy harvesting at multiband frequencies. Previous harvesting platforms were limited to a high-frequency range and exhibited poor electrical performance. Our proposed piezoelectric energy-harvesting platform, which is based on a periodically arranged trampoline metamaterial, exhibits a remarkable electrical output at both low and high frequencies. The proposed harvesting platform broadens the bandgap induced by Bragg scattering in the high-frequency range, and the local resonance is critical in opening a wide bandgap in the low-frequency range. By breaking the periodicity, we generate multiband defect states for flexural wave trapping under fundamental physical phenomena. We experimentally demonstrate flexural wave localization in the defect cavity, while a confined wave is converted into high-performing electrical energy using a piezoelectric element. We measure 1.37 V and 4.05 V as output voltage, and 24.4 & mu;W and 1.28 mW as output power at the 1st and 2nd defect modes, respectively, which are 188% and 400% compared with the bare plate. Our high-power energy-harvesting platform has potential applications as a renewable and sustainable energy source in various fields, such as structural health monitoring, signal processing, and sensors.