Tunable waveguiding in origami phononic structures

A novel design of origami phononic structures with tunable waveguiding features are studied in this research. The structure is formed by attaching cylindrical inclusions on top of origami sheet; in this kind of architecture, folding of the underlying origami sheet can change the periodicity of inclusions. Being periodic in nature, the origami structure exhibits bandgaps features and have the potential to steer wave energy through a path of defects (also known as waveguide) created in the lattice of inclusions. Since the spectral content transmitted through the waveguide depends on the periodicity surrounding it, the folding induced lattice transformation in such origami structures can lead to adaptation in waveguide frequency. In fact, in origami structures that can transform between different Bravais-lattice types, for example between a square and hexagon lattice, the waveguide frequency can be drastically tuned. Such phenomenal adaptation is studied in this research by extracting dispersion diagrams of defective origami structures using the plane wave expansion method. Further, numerical and experimental investigations are performed on finite origami structures with waveguides and the transmission results of different folding configurations demonstrate that waveguide frequency can be significantly altered. Overall, the low effort one-degree-of-freedom (1DOF) folding mechanism combined with the scalable nature of the origami architecture makes the origami phononic structure a novel and effective device for waveguiding applications across a range of frequencies. (C) 2018 Elsevier Ltd. All rights reserved.