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A new ultra-thin sound proofing material inspired by the tiny sound absorbent scales found on the wings of a giant species of moth is being developed thanks to a £1.6 million EPSRC grant. The University of Bristol-led project will see the development of a new prototype material with exciting functional properties –broadband multidirectional absorption at a thickness only fractions of the sound wavelength- to help control noise pollution in cities, offices and homes.
Eye-spot on the hind wing of a Cabbage tree emperor moth (Bunaea alcinoe).
The project builds on earlier work by the Bristol team which revealed the remarkable acoustic camouflage skills of the African Cabbage Tree Emperor moth which evades detection from predatory bats by resonant sound absorption of their echolocation calls (biological sonar).
Dr Marc Holderied, the project lead from Bristol’s School of Biological Sciences, discovered how the fur and thin layer of tiny scales that coat the moth’s wings absorb the bat’s calls by scales that resonate at the typical echolocation frequency range of bats.
A multi-disciplinary team of researchers comprising biologists, mathematicians, engineers and industry will work together to understand the biophysics and biomechanical properties of the moth’s scales and its fibrous porous fur, which are notably more efficient as comparable technical sound-proof solutions. The project will see the development of a noise control prototype material that is much thinner and lighter than existing systems to help the control of acoustics.
Dr Marc Holderied, Reader in Biological Sciences and the project lead, said: “The negative societal and health effects of noise, exacerbated by the increasing population densities in cities, are wide ranging and include cardiovascular disease, cognitive impairment, sleep disturbance, tinnitus, and annoyance. The direct cost to the NHS of hearing loss is estimated to be 450M per year and hearing loss in the UK affects 10 million people.
“This project aims to unlock the potential of evolved deeply subwavelength sound absorbers to develop a new sound absorption metamaterial with lower space and weight footprint that promises more flexible and acceptable noise control solutions for our offices and homes.“
The three-year project entitled ‘Biological metamaterials for enhanced noise control technology’ which commenced in April 2019, has been funded £1.6 million from the ‘Building Collaborations at the Physics of Life Interface’ a joint initiative by EPSRC, BBSRC and MRC.
Source: University of Bristol