Impact of defects and asymmetry on the acoustic transmission of serial resonators

This paper investigates the influence of symmetric and asymmetric defect configurations on the properties of the defect mode in one-dimensional periodic acoustic structures composed of an array of resonators with different boundary conditions at their ends. Numerical computations based on the transfer matrix and the finite element methods (TMM and FEM) are used to explain the influence of defects on wave transmission via localized modes within acoustic band gaps. The results demonstrate that symmetry-breaking defects produce sharper, more tunable defect modes, while symmetric structures exhibit stable, predictable acoustic responses. The geometric defects, including length and cross-sectional area, were shown to significantly affect the frequency of localized modes and the efficiency of acoustic filtering. These results suggest possible applications in the design of tunable acoustic filters and sensors that are enhanced by noise reduction or energy localization.