Elastic wave harvesting in piezoelectric-defect-introduced phononic crystal microplates

The localization of elastic wave at defect in phononic crystals (PnCs) has been applied to design piezoelectric energy harvesting (PEH) devices. However, the earlier researches were based on classical linear elasticity theory, which failed predict structural behavior micron scale. Based a modified couple stress theory (MCST) and mixed finite element method, physics builder COMSOL® Multiphysics is used develop novel interface that can capture microstructure-dependent size effect be simulation PnC-based PEH device. Size dependence newly developed model demonstrated by three sets models different sizes. Numerical results show when considered model, frequencies bandgap bands increase with decreasing compared theory. Furthermore, reduction changes internal stiffness ratio affects displacement amplitude, output voltage electrical power Therefore, effects are inevitable micron-level models. These discoveries would help small-scale devices for enhanced collection.