Bandgap investigation of hierarchical isovolumetric periodic cores with negative poisson ratio
Résumé
The use of periodic media as passive mechanical and acoustic vibration filters has become a research topic of great interest. The classic cores dynamic characteristics have been widely studied and only for very few configurations revealed partial Bragg bandgaps using simple beam models. In this paper, an innovative negative Poisson’s ratio cellular core, derived from the classic re-entrant core geometry is proposed and optimized maintaining constant its overall volume and mass, with the aim of improving its vibration filtering capabilities while leaving its static properties unvaried. The numerical method used to perform this is the Wave Finite Element Method (WFEM) and the optimization focused on obtaining the widest full in-plane bandgap. Harmonic numerical analyses using commercial FEA software are also carried out to validate the bandgaps.