Defected meta-lattice structures for the enhanced localized vibrational energy harvesting

This study focuses on the application of the meta-lattice structures for the energy conversion enhancement in piezoelectric energy harvesters. Three auxetic patterns are designed aiming at efficient energy conversion and a novel phononic crystal is suggested for the mechanical wave manipulation. Based on the supercell calculations, the bandgap features are extracted on the Irreducible Brillouin Zone. The auxetic patterns are embedded in the perfect crystal to act as a functionalized defect, disturb the periodicity of the perfect crystal, and create several bandpasses over the main bandgaps. The defected supercell is located inside a two-dimensional metaplate to investigate its performance in vibration energy harvesting. Numerical modeling of the metaplate is provided in order to show the energy concentration on the defect location and energy harvesting enhancement. The numerical model is validated by experimental tests. It is found that the Auxetic patterns remarkably enhance the performance of the energy harvesting system between 1.29 and 5.26 times in different designs.