Novel cross shape phononic crystals with broadband vibration wave attenuation characteristic: Design, modeling and testing

Abstract

In this paper, elastic wave dispersion characteristics of two novel unit-cells are numerically and experimentally studied. Based on Bloch’s theorem for infinite cellular structures, the Eigen-frequency problem for the unit-cells is solved through a finite element scheme. These novel unit-cells are inspired from Maltese-Cross shape and named unit-cell I and II, while the unit-cell II is created from replacing side ligaments of unit-cell I with triangles. It is observed that these novel unit-cells are capable of providing over 200% phononic bandgap coverage factor over the low-frequency range of 0–12 kHz. Also, the effects of replacing side ligaments with triangles on shifting bandgap pattern to lower frequencies are investigated. The unit-cells are then utilized to construct a metaplate to filter two-dimensional wave’s propagation through the plate. The plate and its cellular segment are simulated with the finite element method, and they are fabricated through laser the cutting process. Frequency analysis is performed on the numerical and experimental models, and results are compared with the bandgaps obtained from periodic Bloch’s theorem. It is shown that a perfect match is observed between experimental and numerical results. The present study provides the practical application of new phononic crystals as a frequency tool to stop the propagation of elastic waves while the location of bandgaps can be tuned with the topology of unit-cells.