The Moth Wing to Sound Absorbing Acoustic Panels

The Biomimicry Alliance wanted to find an alternative method for creating sound absorption materials for application in open office work environments. They posed the question, “How would nature absorb sound?” Through investigation, they discovered the “Cabbage Tree Emperor moth” (Bunaea alcinoe) a moth species belonging to the family Saturniidae, native to Southern Africa. This unique moth can avoid its most notorious predator, a bat, and its “sonar” like ability to track its prey. The moth's wings are covered by overlapping scales that are less than (0.0098 inches) long and have a peculiar porous structure. This structure absorbs the "echolocation" sound of their predator, the bat, and thus helps them to camouflage themselves acoustically. But could The Biomimicry Alliance successfuly emulate the acoustical features of the moth’s wings and apply it to the design of acoustic panels?

The primary project goal was to find creation and analysis tools that would allow them to effectively study, design, analyze and create a working model for real world testing for their proposed acoustic panels. The practical goal was simply to reduce sound bounce that occurs in an open office environment thus making it a less noisy work atmosphere.

Under a microscope on a nanostructure level, researchers discovered that the Cabbage Tree Emperor moth’s wings have scales and other structural forms that aid in the absorption of sound. Together, the Biomimicry Alliance and Autodesk Solution Provider Team D3 used the acquired data and employed the use of Autodesk Dynamo, a computational design software tool, to model the nanostructure of the moth wing. The key to using Dynamo was not only its parametric design capability using logic, but the ability to analyze a digital model without creating a physical prototype. Team D3 created an acoustic panel based off the moth wing, and with the use of another analytic plugin program, Team D3 was able to quickly test the acoustic properties of the digital prototype prior to the 3D printing of a physical model.

The Cabbage Tree Emperor Moth wing panel was then tested in Autodesk Dynamo. The 3D model was generated out of a typical gypsum material as baseline. But even with this hard material, 33% of all sound rays were absorbed by the panels, meaning the moth wing acoustic structure applied to the panel design did aid in sound absorption. The Biomimicry Alliance and Team D3 were satisfied with the results and moved forward with a patent. Without knowing the final results of the testing that is ongoing, it is expected that with the application of a softer material on production panels, that the sound absorption will exceed the 33% reduction noted during the initial testing.

3D models of the product were test printed by way of a 3D printer, and the printed panels are currently being tested in an acoustics lab to further refine the design and the resulting finished product. “Biomimicry is a practice that learns from and mimics the strategies found in nature to solve human design challenges.” Biomimicry designs focus on function insomuch as (they “work like” or simulate nature.) By observation of nature, and in this case, The African Cabbage Tree Emperor Moth, The Biomimicry Alliance and Team D3 were able to apply the biomimicry lesson learned to Industrialized Construction.