Numerical Investigation of Acoustic Metamaterials Using Advanced Finite and Boundary Element Methods

Abstract

Acoustic metamaterials have become a useful subgroup of engineered materials that can couple with sound propagation based with subwavelength structural design, with applications such as acoustic bandgaps, useful sound damping, and novel effective material properties. To be able to describe the intricate wave-structure interactions which are inherent in these systems, such as the accurate and efficient numerical modelling is necessary to avert the design and optimization of these structures. This paper is a detailed numerical study of acoustic metamaterials based on the Finite Element Method (FEM), the Boundary Element Method (BEM), and a hybrid of a coupled Finite Element Method (FEM)-Boundary Element Method (BEM) platform. The model of bounded metamaterial domains with complicated internal geometries is developed through the formulation of the governing acoustic wave equations in the frequency domain, with harmonic excitation, and through the method of discretization by FEM, and the unbounded acoustic medium (around the solid) is modeled by the method of BEM. The strategy to provide continuity of acoustic pressure and normal particle velocity at the interface is adopted with the aim to ensure the wave radiation effective is properly treated (hybrid FEM BEAM coupling strategy). The distribution of the pressure fields, transmission loss spectra, and bandgap of the representative acoustic metamaterial unit cells are analyzed computationally in a broad frequency range by performing numerical simulations. The findings indicate that the combined FEM-BEM method has increased accuracy and enhanced computing efficiency retailers out of the one hand FEM or BEM formulations, especially those that are radiation dominated. The experiment provides a method of strong numerical analysis relevant to the optimization and design of the computational analysis of high-fidelity analysis of next-generation acoustic metamaterials.