Exploiting origami shape reconfiguration in noise control applications

Noise has been recognized as a serious health hazard in modern society. Among various noise reduction ways, control of the transmission path from the source to the receiver is a feasible option for both existing and new facilities. More specifically, acoustic barriers and reactive or dissipative mufflers are two characteristic measures. The performance of a noise barrier or a muffler always depends on geometries. For the former, the key geometry is the barrier height; for the latter, the key geometries are the shape and size of the expansion chamber or resonance tubes. Conventional barriers and mufflers are scarcely capable of altering their key geometries, and hence, their performance based on requirements, nor possessing adequate versatility to adapt to variable noise conditions. In this research, we show that origami, the ancient art of paper folding, provides abundant inspiration for developing reconfigurable noise controlling devices, exemplified by Miura-ori noise barrier, modular-origami silencer, Miura-ori quarter-wavelength tube, and origami-ball expansion chamber. We show that the shape and characteristic geometries of these devices can be significantly altered via folding with a single degree of freedom, which can be exploited for tuning their attenuation performances. Then the modular-origami silencer is employed to exemplify the folding-induced advantages. Finite element studies reveal that folding could reconfigure the silencer such that the sound attenuation bandwidth can be effectively tuned. In addition, by incorporating multiple origami layers in a silencer and by programming their geometries, prescribed noise control requirement can be achieved. Overall, with the modularorigami silencer as a proof-of-concept example, we demonstrate that origami could inspire new innovation in designing noise control devices with the long-desired shape re-configurability and acoustic tunability.