Selective guided wave mode transmission enabled by elastic metamaterials

This article presents the selective guided wave mode transmission enabled by elastic metamaterials. The metamaterial unit cells are comprised of Locally Resonant (LR) cylinders arranged in a periodic pattern bonded on an aluminum plate. Via a careful design, the band structure of the metamaterial system displays a complete bandgap for either symmetric wave modes or antisymmetric wave modes within different frequency ranges. A numerical-based effective medium approach is adopted to calculate the effective dynamic mass densities for in-plane and out-of-plane wave motions under the subwavelength requirement. The finite element harmonic analysis of a chain model further substantiates the selective mode transmission capability via the frequency spectrum of the transmitted wave modes. Finally, a coupled-field transient dynamic finite element simulation is carried out to acquire the dynamic response of the structure. The frequency-wavenumber analysis of the transmitted wave field illuminates the successful achievement of the selective mode transmission behavior. Experimental demonstrations are also presented to validate the numerical predictions. The proposed selective wave mode transmission control capability may possess great application potential in Nondestructive Evaluation (NDE) and Structural Health Monitoring (SHM). The paper finishes with summary, concluding remarks, and suggestions for future work. (C) 2020 Elsevier Ltd. All rights reserved.