Perforation-rotation based approach for band gap creation and enlargement in low porosity architected materials

Artificially designed Perforated architected materials (PAMs) have attracted growing attention in recent years due to its relatively simple fabrication process and unusual physical properties for potential applications. Despite numerous works on configuration optimization, few studies have explored the role of perforation orientation on band gap structures of PAMs. In this study, based on adjusting the orientation of holes we propose a novel design approach for low porosity PAMs, which can effectively create and enlarge the band gaps. Both experiments and numerical analyses all demonstrate that the perforation rotation in a two-dimensional periodic structure of mutually orthogonal rectangular holes can be manipulated to form band gaps. Compared with the baseline configuration, a new wide band gap with the gap-to-midgap ratio up to 81% is achieved in the revolved configuration at a small pore volume fraction. This band gap can be created and enlarged by breaking of structural symmetry and the resulted destructive interferences modify the mode shapes and frequencies of the periodic architected materials. This approach may open promising avenues for designing metamaterials with broadband wave attenuation in low porosity.