  The quest for novel designs for lightweight phononic crystals and elastic
metamaterials with wide lowfrequency band gaps has proven to be a significant
challenge in recent years. In this context, lattice-type materials represent a
promising solution, providing both lightweight properties and significant
possibilities of tailoring mechanical and dynamic properties. Additionally,
lattice structures also enable the generation of hierarchical architectures, in
which basic constitutive elements with different characteristic length scales
can be combined. In this work, we propose 1D- and 2D-periodic phononic crystals
made of spatial frames inspired by a spider web-based architecture.
Specifically, hierarchical plane structures based on a combination of frames
with a variable cross-section are proposed and exploited to open and enhance
band gaps with respect to their non-hierarchical counterparts. Our results show
that hierarchy is effective in broadening existing band gaps as well as opening
new full band gaps in non-hierarchical periodic structures.

Applied Physics