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Study on the bandgap and wave propagation characteristics of tetrachiral and star-shaped hybrid metamaterial

In this paper, an innovative tetrachiral and star-shaped hybrid metamaterial (TSHM) composed of periodic assembly of single-phase lightweight materials is proposed. Based on the finite element method, the band structure of TSHM and the correlation between the bandgaps and geometric parameters are investigated. In addition, the visualization mode provided by the finite element software COMSOL Multiphysics 5.5 is used to explore the formation mechanism of the bandgaps. Furthermore, by drawing iso-frequency contours and group velocities, the directionality of elastic wave propagation in TSHM and the anisotropic behavior of metastructure are intuitively expressed. Finally, the wave regulation effect of the two-dimensional (2D) sandwich panel formed by the TSHM core is studied and the frequency response functions (FRFs) are plotted, which is another way to characterize the bandgap properties. Our research shows that the proposed periodic metamaterial has excellent wave attenuation performance in multiple frequency ranges, which will provide a valuable reference for vibration and noise reduction projects.