Experimental validation of low-frequency tunable bandgaps in 3D-printed Miura origami metastructures

We experimentally demonstrate the presence of low-frequency bandgaps, below 1000 Hz, in Miura origami metastructures that can be tuned by geometric reconfiguration achieved by changing the folded state. Bandgaps, defined as frequency ranges that inhibit wave transmission through the medium, have implications for applications involving the maneuvering of elastic wave propagation. However, there is a lack of 3D-printing-based techniques capable of fabricating foldable origami metastructures that exhibit tunable bandgaps. To address this gap, we introduce a novel 3D-printing-based fabrication procedure for origami metastructures which are stiff at a desired folded state, while enabling temperature-assisted reconfiguration to another folded state. To mimic origami crease-type folding, we incorporate profiled creases in the 3D-printed specimens. Dynamic tests on these specimens demonstrate the presence of low-frequency bandgaps, which are shown to be significantly tunable by changing the folded state. A novel strategy of introducing bending creases effectively enhances the ease of panel bending, and widens the bandgap by more than 25%. We further show that, changing the folding-angle by about 15° can almost double the width of bandgap, or, shift the bandgap frequency by more than 30%. The tunable bandgaps obtained experimentally from 3D-printed specimens are also supported by numerical finite element simulations, in which compliant creases and relatively stiffer panels have been modeled using shell elements. Comparing results across specimens 3D-printed using different printers and resolutions demonstrates that metamaterial bandgaps are primarily governed by unit cell geometry and largely independent of microstructural details. The tunable bandgaps obtained in our foldable origami lattices show promise for a wide range of wave-propagation-based applications, including acoustic cloaking and waveguiding. • Novel procedure for 3D-printing and temperature-based reconfiguration of foldable origami. • Demonstration of tunable low-frequency bandgaps by virtue of folded state. • Finite element modeling and simulation to validate bandgap characteristics of origami metastructure. • Geometric dependence and microstructure independence of bandgaps in origami metastructures.