Engineers will relieve passengers from the hum of engines

Engineers from the University of North Carolina and MIT have developed a fundamentally new sound insulation to dramatically reduce the level of low-frequency noise penetrating the cabin. The insulation is made in the form of a membrane adjacent to the panels from which the aircraft is made.

Yun Jing, an assistant professor at the aviation faculty of the university, and the main author of the work, explains: "This type of insulator should be excellent for making durable, lightweight and soundproof structures."

When traveling by plane there are many unpleasant features, and one of them is the hum of engines. Noise accompanies you throughout the flight, and earplugs do not save from it - they are generally poorly protected from low-frequency sounds. However, it was impossible to do serious soundproofing of the cabin up to this point, because the designers are trying in every way to reduce the weight of the aircraft. The panels that make up the design of the aircraft, have a cellular structure resembling a honeycomb. This structure has good durability with low weight - but very poor sound insulation.
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Scientists have developed a membrane, which, being stretched on one part of the cellular structure, does not allow sound vibrations to pass through itself - the sound is reflected back from it. “It is especially effective at coping with low frequencies,” says Jing. “It cuts off 100-1000 times more sound energy of waves with a frequency up to 500 Hz, than a simple cellular panel without a membrane.”

An inexpensive rubber membrane has a thickness of 0.25 mm and increases the total weight of the panel by no more than 6%. Scientists hope that this design of the panels will help to increase the comfort of passengers using air travel.