World’s first 3D acoustic cloaking device created

Metamaterials are already being used to create invisibility cloaks and ” temporary layers, ” but now the engineers at Duke University have made the task of metamaterials to create a 3D acoustic layer. In the same way that invisibility cloaks using metamaterials to bend light around an object , the device interacts with camouflage acoustic sound waves to make it appear as if the device and nothing hidden under it is not there.

Steven Cummer , professor of electrical and computer engineering , and his colleagues at Duke University built his acoustic cloak using multiple sheets of plastic plates dotted with repeating patterns of holes. Plastic films , that were created using a 3D printer , were stacked one above the other to form a device that resembles a pyramid in shape . The blade geometry and positioning holes interact with sound waves to make it appear as if the device and anything that sits below it is not there.

Despite its apparent simplicity , the construction of the device was far from a casual affair , with a lot of time and research into the calculation of how sound waves could interact with it. As Cummer says , ” we have not come up with tonight. ”

Research scientist with Bogdan Popa acoustic device built with 3D camouflage Compon …
Research scientist Bogdan Popa a 3D acoustic cloaking device built with components created in a 3-D printer (Photo : Duke Photography )

To work effectively , the mantle has to alter the path of sound waves to behave as if they had reflected on a flat surface. To achieve this, the device needs to reduce the speed of the sound waves to compensate for the fact that they are not traveling in the measurement.

To test the effectiveness of the layer, the researchers took a small sphere and covered with the mantle . Then ” ping ” the area with short bursts of sound from various angles and how the sound waves mapped responded using a microphone. The team produced videos of the sound waves that travel through the air and compared with the videos produced with mantle removed and another that shows the behavior of sound waves with a flat surface without obstructions.

The results showed that the acoustic layer made ​​it appear as if the sound waves are being reflected on a flat surface with no sign of the field was there. Unlike the ” cloak of silence ” , developed at the Karlsruhe Institute of Technology in Germany that worked only in two dimensions, this was true regardless of the direction of the sound originated or where the observer were found , which led the team to call his creation of the ” world’s first acoustic cloaking device in 3D. ”

Cummer believes technology has numerous potential commercial applications.

” I We conducted our tests in the air, but sound waves behave similarly under water , so an obvious potential is avoid sounding use ” said ” But there is also the design of auditoriums and concert halls – . any space that you need to control noise . If you were to put a beam somewhere for structural reasons that would spoil the sound, maybe you could correct for the acoustic cover it.