Origami-Engineered Acoustic Metastructures: Tunable Solutions for Low-Frequency Sound Absorption

The need for quieter spaces is becoming more pressing in fields like transportation, aerospace, and architecture, which is why sound absorption and noise control are such active areas of research. Low-frequency noise is especially tricky to handle. It carries a lot of energy, travels long distances, and takes forever to fade away. This type of noise can make life uncomfortable, increase stress levels, and even harm health, whether at home or at work. Despite the progress made in acoustic engineering but to figure out how to effectively deal with low-frequency noise is still a tough nut to crack. Take conventional sound absorption methods, for example—things like porous materials and micro-perforated panels. They often work by being thick enough to match the wavelength of the sound they are targeting. That is fine in theory, but in practice, it means creating bulky, heavy structures. These are not ideal for planes, cars, or tight architectural spaces where keeping things lightweight and compact is essential. What is worse, many of these solutions are built for a specific range of frequencies. They cannot adapt when noise levels or types change, leaving them stuck in a one-size-fits-all design. This is where acoustic metamaterials come into the picture. These are engineered materials that manipulate sound waves in clever, unconventional ways. They have shown a lot of promise, especially because they can create lightweight and compact systems that deal with low frequencies much better than traditional materials. But even these innovative materials are not perfect. Many of them are still stuck with fixed absorption properties, making them less useful in real-world situations where noise sources and frequencies tend to vary. To tackle these challenges, new research paper published in Journal of Finite Elements in Analysis and Design and led by Professor Yao Chen, Zerui Shao, Jialong Wei, and Professor Jian Feng from the Southeast University in China, together with Associate Professor Pooya Sareh from the Newcastle University in UK, explored the potential of origami-inspired engineering. They used the Miura-ori folding technique to create a new type of acoustic metastructure with adjustable properties. Origami stood out because it is inherently flexible, compact, and capable of dynamically reconfiguring its geometry. The team believed that this unique folding method could sidestep the issues of traditional designs and offer a solution that adapts to low-frequency noise more effectively.

The researchers used advanced numerical simulations based on finite element modeling  to evaluate how well the Miura-ori foldcore sandwich acoustic metastructure (MOF-SAM) could absorb sound. They relied on a software tool called COMSOL Multiphysics, which allowed them to include thermoviscous effects and pressure acoustics in their analysis. This approach let them study in detail how the geometry of the origami-inspired design affected sound absorption, especially at low frequencies where noise is tough to manage. The authors also focused on designing and testing the Miura-ori foldcore itself and they modeled it as a series of connected parallelograms that could fold into complex, three-dimensional shapes. These folds created cavities that acted as acoustic resonators when combined with a perforated top panel and a rigid base. By simulating how sound waves traveled through these cavities, they could see how structural vibrations and airflow helped absorb sound. Their findings were impressive: the MOF-SAM achieved a peak absorption coefficient of 0.9271 at around 760 Hz.

The team also experimented with different design features to understand their impact on performance. For example, increasing the diameter of the perforations shifted the resonant frequency to higher levels. On the other hand, thicker panels brought the frequency down because the longer perforations acted like extended necks in the Helmholtz resonators. These experiments showed how the metastructure’s sound absorption could be fine-tuned by tweaking specific parameters. Another important finding came when they compared the MOF-SAM to traditional honeycomb acoustic designs. The Miura-ori foldcore outshined honeycombs, which typically max out at an absorption coefficient of around 0.63. In contrast, the MOF-SAM hit nearly perfect absorption at 0.9996, with a resonant frequency of 1020 Hz. This demonstrated how much more effective the origami-based design was, particularly for low-frequency noise. The foldability of the Miura-ori design proved to be another game-changer.

To wrap things up, the work led by Professor Yao Chen and his team makes an impressive contribution to acoustic engineering by tackling one of its most stubborn challenges—how to effectively absorb low-frequency noise without relying on bulky or rigid materials. Through their innovative use of an origami-inspired Miura-ori foldcore design, they showed how geometric flexibility can bypass the limitations of traditional sound-absorbing methods. This design makes it possible to create lightweight and compact structures that perform exceptionally well in low-frequency sound absorption, where conventional approaches tend to fall short. The practical applications of their research are incredibly broad. The tunability of the Miura-ori foldcore is a game-changer and can offer the ability to dynamically adjust the metastructure’s sound absorption capabilities to match shifting noise conditions. This adaptability is particularly valuable in fields like aerospace, where keeping weight low while maintaining high performance is crucial. It is also a big win for transportation industries, where reducing noise not only makes for a more comfortable passenger experience but also helps meet environmental standards. Another key takeaway is the potential for scalability and customization. The modular design of the Miura-ori foldcore means it can be tailored to a wide variety of uses, whether it is for reducing urban noise in architectural projects or improving soundproofing in machinery and vehicles. The ability to tweak parameters like cavity size, panel perforation, and fold angles adds a level of precision in acoustic performance that is hard to achieve with older materials like porous absorbers or honeycomb panels.