Scientists have designed a novel structure that completely absorbs sound at a wide range of frequencies, an advance that may allow for new solutions to reduce noise pollution caused by roads, railways, etc.
Researchers created the new structure from conventional porous materials used in the construction industry.
"Our study tackles one of the most important problems of society today from a new point of view: the design of materials and surfaces able to significantly reduce noise," said Victor Sanchez-Morcillo, researcher at the Campus de Gandia of the Universitat Politecnica de Valencia in Spain and director of the Master's Degree in Acoustic Engineering, taught at the campus.
"In view of the results, we believe we have taken an important step toward the perfect absorber. And that has been done just by reconfiguring a known material," Sanchez-Morcillo said.
The researchers have demonstrated how the designed structure achieves extraordinary sound absorption using an apparently contradictory strategy: the sound attenuation increases when the quantity of absorbent material is reduced.
This way, a totally reflective surface becomes a perfect absorbent despite the fact that, for the most part, there is no material that absorbs sound.
The key to understanding this reaction is the following: the new configuration of the material, in periodically distributed panels, allows sound waves to easily enter the material and increases the interaction between it - the wave - and the structure, thereby increasing the absorption.
Sanchez said that the study's conclusions open a new way to design new noise reduction solutions such as the development of new baffles to reduce noise pollution caused by roads, railways, etc.
The Technical University of Denmark, the LUNAM Universite of Le Mans (France) and the Institute of Photonic Sciences (ICFO) were also included in the study.
The research was published in the journal Scientific Reports.
