A 250 million-year-old insect inspires the manufacture of sound-absorbing wallpaper!
The sound-absorbing fur wings of a 250-million-year-old moth could be the key to sound-absorbing materials in the future.
At the time when the dinosaurs became extinct about 65 million years ago, bats, the main predators of moths, evolved their ability to echolocation.
Some species, such as the furry silk moth, do not have ears at all, but rather use another defense mechanism, the sound-absorbing wings.
So-called acoustic camouflage was discovered in 2018, when a team of researchers at the University of Bristol found that furry moths have a coating on their wings that can absorb up to 85% of the sound waves that strike them, making them difficult to locate.
And now a recent study by the same research team indicates that the wings of this moth can absorb new types of ultra-thin acoustic materials.
And because nature always inspires humans to find solutions to their problems, they have designed aircraft wings modeled after birds, cooling vents inspired by mounds of termites, and bird-safe glass inspired by UV-reflecting threads in spider webs.
Moths evolved about 200 million years before bats, according to Kings Holred, professor of sensory biology at the University of Bristol and co-author of the new study with Thomas Neal. Furry mites had scales on their wings even before bats arrived, possibly to protect themselves from sticky spider webs.
After six years of effort, scientists concluded that earless moths had to rely on their vocal wings to survive. They learned this by studying the fine dust on their wings.
When sound hits these dust particles at the right frequency, they start vibrating, and by this vibration they take sound energy from the air and convert it into mechanical energy that will eventually be damped and converted into heat. This process is known as resonance absorption. .
This new material acts somewhat like the ultra-thin texture of wallpaper applied to a variety of surfaces from office walls to airplane seats.
“We are talking about something that is measured in millimeters instead of centimeters,” says Holdid, noting that resonant materials will be more efficient than the porous materials used in conventional acoustics, and when the material is thinner it will be lighter, which may help, for example, to reduce the overall weight. for the aircraft and to save fuel.
The Holdid team is working on several prototypes made of something called a metamaterial. These engineered materials are made of a large number of cells that would mimic how a moth's wings function.
The challenge now is to translate the concept so that it works with the human audible range. Until now, scientists have used ultrasonic signals above the range humans can hear. But Holloride says the size of each scale on the metamaterial can help determine what kind of sounds it can absorb. Which is promising.
It will likely be a few years before this material reaches the market, but if it does, it would be the culmination of 250 million years of work.
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