Revolutionizing Sound Absorption: A New Physics Breakthrough
The Challenge:
Designing spaces that are both well-ventilated and sound-absorbent can be a complex task. Materials that allow air to flow, like vents, often let sound escape, making noise reduction difficult. Conversely, sound-absorbing materials like foam can block airflow, limiting their use in ventilated areas.
The Breakthrough:
A research team led by Professor Nicholas X. Fang from the University of Hong Kong (HKU) has made a groundbreaking discovery. They've identified a fundamental physical principle called duality symmetry, which opens up new possibilities for designing ventilated sound-absorbing materials.
The Discovery:
The team, in collaboration with Professor I. David Abrahams from the University of Cambridge and Acoustic Metamaterials Group Ltd., found that duality symmetry governs the absorption bandwidth of a ventilated system. This means that symmetry and absorption bandwidth were previously unrelated concepts, but their derivation reveals a deep mathematical connection.
The Innovation:
They designed a unique ventilated structure with two connected acoustic chambers. This setup allows air to flow freely while trapping and dissipating sound energy through destructive interference, significantly enhancing noise reduction.
The Results:
Experiments showed that this innovative material can absorb over 86% of sound across a wide range of frequencies, from low (300 Hz) to high (6000 Hz), outperforming traditional foam panels. The researchers also introduced a new performance measure called the Figure of Merit (FOM), which evaluates the system's effectiveness across bandwidth, thickness, and airflow.
Challenging Established Limits:
Traditionally, the 'causality constraint' principle sets a theoretical limit between material thickness and bandwidth. This new study challenges those limits for ventilated systems and offers a new design approach based on duality symmetry.
The Impact:
This breakthrough could lead to quieter buildings, improved noise control in aircraft engines, and more effective damping solutions in various engineering fields. With AI and advanced simulation techniques, this technology has the potential for real-world applications, making our environments quieter and more comfortable without compromising ventilation.
Link to Research:
https://doi.org/10.1038/s41467-025-65786-w
About Professor Nicholas Fang:
Professor Fang's research focuses on wave physics at sub-wavelength scales, with applications in energy conversion, communication, and biomedical imaging. His work has led to over 16 patent applications in nano- and micro-fabrication, additive manufacturing, and imaging technologies, successfully transferred to industry and startups.
