Experts at the University of Bristol have been studying whether a moth’s structure could inform better performing sound-absorbing panels, when not moving in free space.
Bats and moths have been involved in an acoustic arms race between predator and prey ever since bats evolved echolocation some 65 million years ago.
Researchers figured out that a moth’s wings hold the key to transforming noise-cancelling technology.
Remarkably, they found that moth wings proved to be excellent sound absorbers, even when on top of an acoustical solid substrate, with the wings absorbing as much as 87% of the incoming sound energy. The effect is also broadband and omnidirectional, covering a wide range of frequencies and sound incident angles.
What is even more impressive is that the wings are doing this whilst being incredibly thin, with the scale layer being only 1/50th of the thickness of the wavelength of the sound that they are absorbing.
The potential to create ultrathin sound-absorbing panels has huge implications for building acoustics. As cities get louder, the need for efficient non-intrusive sound mitigation solutions grows. Equally, these lightweight sound-absorbing panels could have huge impacts on the travel industry, with any weight saving in planes, cars and trains increasing efficiency in these modes of transport, reducing fuel use and CO2 emissions.
Now the scientists plan to replicate the sound-absorbing performance by designing and building prototypes based on the sound-absorbing mechanisms of the moth.
“New research has shown that one day it will be possible to adorn the walls of your house with ultrathin sound absorbing wallpaper, using a design that copies the mechanisms that give moths stealth acoustic camouflage.”