Reconfigurable metamaterial for asymmetric and symmetric elastic wave absorption based on exceptional point in resonant bandgap

Abstract Elastic wave absorption at subwavelength scale is of significance in many engineering applications. Non-Hermitian metamaterials show the ability high-efficiency absorption. However, single functionality an important limitation on their practical applications for lack tunability and reconfigurability. Here, we propose a tunable reconfigurable non-Hermitian piezoelectric metamaterial bar, which bars connect with resonant circuits, to achieve asymmetric unidirectional perfect (UPA) symmetric bidirectional (PA) low frequencies. The two functions can be arbitrarily switched by rearranging shunted circuits. Based reverberation-ray matrix (RRM) method, approach provided UPA setting exceptional point (EP) coupled bandgap. By using transfer method (TMM) finite element (FEM), it observed that pseudo-band forms between bandgaps, EP appears bottom pseudo-band. In addition, genetic algorithm used accurately efficiently design circuits desired low-frequency PA. present work may provide new strategies vibration suppression guided waves manipulation wide potential