Active feedback control of sound radiation in elastic wave metamaterials immersed in water with fluid–solid coupling

Abstract

Due to their potential properties unlike traditional materials and structures, elastic wave metamaterials have received significant interests in recent years. With the coupling between the acoustic and vibration, their mechanical characteristics can be tuned by the active feedback control system at low frequency ranges in which the traditional passive control is limited. This work illustrates that the superior performances of the effective mass density and sound pressure level (SPL) of an elastic wave metamaterial can be significantly changed by the active control, in which the periodic array of local resonators and orthogonal stiffeners are included. Significantly, based on the locally resonant mechanism, the negative density occurs over a frequency range. Due to the effects of lattice constant, structural damping and other parameters, the SPL with the function of fluid–solid coupling are illustrated and discussed.