Abstract
This article explores an innovative vibration suppression design, termed octuple-action (OA), for acoustic metamaterial plates, aimed at mitigating the propagation of acoustic waves. The design's goal is to create broad frequency stopbands, which can be configured by adjusting passive parameters governing the locally resonant subsystems of the OA absorber. The metamaterial plate is structured with a sequence of evenly spaced OA vibration absorbers that are attached to an isotropic plate. Each OA vibration absorber is composed of two separate spring-mass-damper subsystems, interlinked to each segment of the isotropic plate at eight uniformly distributed locations through elastic couplers. An analytical methodology is developed, utilizing finite element modeling (FEM) and Bloch's theorem, to elucidate the presence of stopbands, resulting in the formation of a single configurable and unified frequency stopband, or two broad stopbands. A comprehensive analysis and illustration of the proposed metamaterial plate's OA vibration absorber are presented. The OA vibration absorber effectively impedes the propagation of acoustic waves through the metamaterial plate by generating a set of eight internal forces. These forces act in a manner that counteracts any incoming wave with a frequency residing within the designated stopband ranges. Furthermore, by optimally manipulating the effective material properties of the OA, the internal forces can be tailored, enabling the creation of configurable and broad stopbands. To comprehensively examine the influence of the OA vibration absorber's subsystem parameters on the characteristics of the stopbands, a rigorous parametric investigation is undertaken. This investigation focuses on how variations in mass densities and stiffness coefficients impact the stopband locations and widths. The excellent agreement observed between the FEM simulation results and the dispersion curves across a wide range of prescribed configurations and patterns serves as robust validation for the efficacy of the proposed metamaterial design incorporating the OA vibration absorber.
