Anti-noise panels based on “labyrinthine” metamaterials capable of absorbing sound waves transmitted into the environment. This is the new technology, designed by six students of the Alta Scuola Politecnica (Asp), the international program reserved for the best students of the Milan Polytechnic and Turin Polytechnic, which promises significant noise attenuation, achieved thanks to the internal structure of the panels. Asp explains that these structures, defined as “metamaterials” because they exceed the potential of conventional materials, have innovative acoustic properties. Their performance is not due to the components with which they are produced, but to their labyrinthine geometric shape, which can be easily reproduced. The sectors of application are various, from construction to automotive, up to domestic use.
Leonardo Bettini, Venus Hasanuzzaman Kamrul, Emanuele Musso, Fabio Nistri, Davide Piciucco and Matteo Zemello are the six students of the Asp who designed the panel. The labyrinthine structures present inside make the acoustic wave reflect several times, which slowly reduces until it is self-canceling. It is as if the acoustic noise is “lost” inside the labyrinth. These structures are able to dampen various types of noise: from medium frequency sounds, typical of speech and some musical instruments, to low frequency ones, caused by motors.
The work demonstrated that labyrinthine metamaterials have high potential, as their lightweight, space-saving and 100% 3D-printed structure, makes it possible to build acoustic products with waste plastics, without compromising the performance of the panel, but managing to reduce the final costs. A possible sector of use could be that of aeronautics. The application of the panel in the fuselage of an aircraft would allow both to isolate the passengers inside from external noise, and to reduce the environmental noise pollution caused by the aircraft.
The project was tested and validated at the “Galileo Ferraris” Energy-Denerg Department of the Politecnico di Torino, with the support of professors Federico Bosia, Louena Shtrepi and Antonio Gliozzi. He was also involved as an industrial partner Phononic Vibes, a company founded in 2018 as a spin-off of the Politecnico di Milano. The project will continue as part of the European research path Fet – Boheme, coordinated by the University of Trento and in which the Polytechnic of Turin, the Imperial College of London and the Federal Polytechnic of Zurich (Eth) are involved among others. .