The sound stealth device, as the name suggests, avoids the equipment that is observed through sound. This technology can work at any angle, no matter where the sound comes from or where the observer is located, it can be found. This technology is expected to be used in sonar avoidance and architectural acoustics in the future.
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Steven Cummer, a professor of electrical and computer engineering at Duke University in North Carolina, United States, said that the special feature of the cloak is to hide objects from the sound waves and cover the object with the cloak. The sound waves behave like nothing there. A plane." In order to achieve this goal, Cummer and his colleagues turned to metamaterials, using artificial materials in a repeating pattern of natural materials. In order to develop new acoustic capes, the materials that manipulate the behavior of sound waves are plastic and air. When set up, the device looks like several repeating patterns of porous plastic substrates stacked together, similar to a pyramid.
In order to create the illusion that there is no object below, the cape must change the trajectory of the sound wave to match the reflection on the plane. Because the sound cannot reach the lower surface, the transmission distance is shorter and the speed must be slowed down to compensate.
Cummer said in a statement: "The structure we built looks simple... but I assure you this is a very complex structure and it looks more interesting than it looks. We devote a lot of energy to calculating how sound waves will This is not an overnight event.†To test the stealth device, the researchers used a cloak to cover a small sphere and then fired short bursts of sound from different angles. They use a microphone to draw the acoustic response and make a video of the sound waves through the air. The experimental results show that the cape behaves like a sound wave reflected on an empty surface in sound waves.
Experiments have shown that this technology is feasible, and Cummer believes that this technology has several potential commercial applications. We tested in the air and underwater sounds were similar, so an obvious potential application is to avoid sonar, Cummer said, but the design of the auditorium, the concert hall—anywhere you need to control the sound can also be applied. The study was funded by a multidisciplinary university research program from the U.S. Maritime Research Office and the U.S. Land Research Office.