"Modern soundproofing is literally thick walls," said researchers from the team of Boston University professor Xin Zhang.
Their project is not at all similar to traditional approaches: it uses a metamaterial, the properties of which are determined not by its composition, but by the details of the form and structure. In a paper published in the journal Physical Review B, scientists describe and demonstrate such a structure - open, like a series of rings through which a free stream of air can flow, but almost no sound escapes.
Physicists began by mathematically modeling the shape and size of a metamaterial that would efficiently redirect acoustic waves back to their source. After producing such a structure using a 3D printer, the scientists fixed it to the end of a plastic pipe, at the opposite end of which a speaker was placed. He reproduced an annoying and harsh sound, however, even putting his ear to the pipe, he could not hear it. But as soon as the ring structure was removed from the pipe, an unpleasant sound filled the room.
Inspired by the successful confirmation of their calculations in the laboratory, scientists immediately find a lot of promising applications for such technology. Indeed, street and industrial noise has become a real problem today, and with the proliferation of drones (the buzzing of which is considered one of the most uncomfortable background noises) it threatens to worsen even more. Therefore, such metastructures can be widely used to reduce noise from drones, fans and air conditioners - industrial and domestic.
"If we can place the structure under the blades, we will suppress the sound going down," the authors of the paper promise. - Its external shape can be cubic, hexagonal - any. If we need to make a wall out of them, we can use hexagons. " Let's hope scientists will be able to put the technology into practice, and then our life will become at least a little quieter.
