Electromechanical behavior of 3-3 piezoelectric star-shaped metamaterial with four types of connection

This study presents the complete electromechanical properties of 3-3 piezoelectric metamaterial based on variants of star-shaped cellular structure. Four types of three-dimensional piezoelectric star-shaped metamaterial (3D PSSM) with different connection modes (with symmetric interconnects, with asymmetric horizontal interconnects, with asymmetric vertical interconnects and without any interconnects) are introduced. Periodic boundary conditions are applied to unit cell of 3D PSSM. And the finite element analysis is implemented to investigate the effect of different structural parameters and poling directions (longitudinal and transverse) on the effective electromechanical response. Compared with the monolithic piezoelectric materials, different connection modes of the 3D PSSM show different combinations of enhanced electromechanical response and figures of merit. For example, longitudinally poled 3D PSSM with symmetric interconnects has both higher hydrostatic strain coefficient (dh) and hydrostatic figure of merit (d(h)center dot g(h)), and lower acoustic impedance (Z), indicating it is more suitable for the design of hydrophones; longitudinally poled 3D PSSM with asymmetric interconnects has higher piezoelectric coupling constant (k(t)), indicating that this structure is more suitable for the design of energy harvesters.