Topology optimization of sub-chambers in a reconfigurable modular origami silencer for tunable and broadband sound attenuation

Origami offers abundant design possibilities and exceptional reconfigurability, making it a rich source of inspiration for acoustic device design. In this paper, we propose an innovative design of modular acoustic silencers by incorporating topology optimization techniques with origami-inspired concepts. Specifically, the internal fillers in the silencer sub-chambers are topologically optimized to target specific frequencies for effective sound attenuation, aiming to achieve over 10 dB attenuation across a broad frequency range from 600 Hz to 1800 Hz. Unlike conventional methods that only alter chamber sizes, our approach utilizes advanced topology optimization tools to shape the internal fillers, enabling precise tuning of the effective frequency range without modifying the external size of the silencer. This ensures modular stacking and acoustic programmability. By cascading multiple topologically optimized modules, we can further achieve broadband sound attenuation over a much wider frequency band. The transmission loss behavior can also be strategically adjusted through the folding mechanism. As a proof-of-concept, we fabricate modular origami silencer prototypes with internal fillers by using 3D-printing technology. Experiments are conducted to validate our simulations and the topology optimization process, demonstrating the effectiveness of broadband sound attenuation through cascading multiple chambers, and the distinctive adjustability offered by folding. Overall, this research brings about fresh perspectives for the design, optimization, deployment, and customization of acoustic silencing devices.