Origami-inspired acoustic metamaterial with tristable property and tunable sound absorption

Abstract

Noise reduction is essential in engineering applications, and flexible impedance tuning in acoustic metamaterials, which enables low-frequency broadband absorption, has garnered attention within the physics and engineering research communities. However, traditional acoustic metamaterials suffer from fixed absorption bands due to their rigid cavities. We break this limitation by replacing the cavity walls of a Helmholtz resonator with Kresling origami sheets, creating the first tristable origami-inspired acoustic metamaterial (OIAM), enabling dynamic absorption frequency tuning through structural reconfiguration. By integrating theoretical modeling, numerical simulations, and experimental validation, our research successfully illustrates that the OIAM achieves tunable absorption frequencies (149 Hz, 180 Hz, and 275 Hz) with $\alpha >0.95$ at a subwavelength thickness of 1/22$\lambda$, corresponding to its three stable states—the first demonstration of state-switched broadband tuning in Kresling pattern origami. The truss model shows that the angle parameter affects the stable states of the OIAM, enabling modes such as zero-stiffness, bistability, and tristability, as seen in compression tests. Compared to a single unit, the four-unit parallel OIAM can effectively broaden the absorption bandwidth by 230%. The multi-stable properties enhance energy absorption, load-bearing capacity, and multifunctionality, while the foldable design ensures convenient installation and transportation. In summary, our flexible design offers an effective solution for engineering applications that demand tunable sound absorption and load-bearing capacity.