Vibro-acoustic performance of graded piezoelectric metamaterial plates

This work investigates the vibro-acoustic performance of graded piezoelectric metamaterial plates. A piezoelec-tric layer with electrodes segmented in a regular lattice is attached over a rectangular, simply-supported panel to realize the electromechanically coupled metamaterial plate, rendering a geometrically periodic structure. The grading is achieved in the electric domain, as each unit cell's inductive shunt resonant frequency can be tuned independently. We investigate two first-order grading patterns based on linear variations along one and both dimensions of the plate and evaluate their impact on vibration attenuation, sound power, kinetic energy, and acoustic radiation efficiency. The graded metamaterial plates outperform the periodic locally resonant counterparts in vibration and radiated sound power attenuation. Moreover, sound radiation efficiency may increase within the attenuation band for steep grading patterns related to the vibration localization phenomenon. The results show that piezoelectric metamaterial plates with reconfigurable properties are an interesting alternative for enhanced vibro-acoustic performance.