Dual-Functional Star-shaped Metamaterial for Simultaneous Vibration Isolation and Energy Absorption

Abstract

A novel star-shaped metamaterial (SSM) is proposed to achieve simultaneous vibration isolation and energy absorption capabilities. The band structure of the proposed SSM is given based on the Floquet-Bloch theorem with boundary modes of each bandgap analyzed to understand the effects of each component of the unit cell on the bandgap formation. It is found that the SSM triggers monopole, dipolar and quadrupolar resonances to form locally resonant bandgaps and exhibit equivalent negative parametric characteristics. The SSM can generate the lowest bandgap frequency of 53.149 Hz and bandgaps (lower-frequency and broader bandgaps) are highly sensitive to geometric properties angle $\theta$ based on parametric analysis. Additionally, vibration isolation and energy absorption performance can be enhanced by introducing a gradient parameter with angle $\theta$ into the SSM structure. The design of the gradient structure breaks local symmetry, opening the Dirac points to generate a new bandgap. Furthermore, uniaxial compression induces different buckling deformation, enabling the gradient structure to achieve superior energy absorption performance under the same loading conditions. This study proposes a dual-functional SSM that integrates vibration isolation and energy absorption, providing a potential pathway for multifunctional metamaterial design.