A multi-bandgap metamaterial with multi-frequency resonators

A 2D metamaterial cellular system inspired by lightweight honeycombs and spider webs is investigated. The hexagonal cells of the honeycomb act as hosting substructures for spider-web-like or cantilever resonators with added lumped masses which can vibrate, in principle, in any of the infinitely many modes. Contrary to traditional approaches utilizing discrete mass-spring resonators, here the infinite-dimensional (full spectrum) resonators are intentionally tailored to generate multiple, complete or incomplete, stop bands across which wave propagation is either totally or partially suppressed along preferential directions. The Plane Wave Expansion method is employed to obtain the dispersion curves and the bandgap sensitivity with respect to the design parameters. Experimental results based on laser scanning vibrometry corroborate the theoretical predictions and confirm the robustness of the stop band behavior with a wealth of results which pave the way towards suitable optimization strategies and a closer understanding of these formidable stop band cellular material systems.