Broadband wave filtering of bioinspired hierarchical phononic crystal

Broadband wave filtering effect is observed in a phononic crystal with hierarchical structure inspired by biocomposites. Through a multilayered model with hierarchical structure, it is demonstrated that the overall bandwidth covered by closely adjacent bandgaps for this structure is orders of magnitude broader in frequency than that of conventional periodic structure with single periodicity. This remarkable feature is attributed to the inherent multiscale periodicity in the microstructure, which roughly superimposes the bandgaps generated by individual periodic structures with periods corresponding to those at different hierarchies in the hierarchical structure.