Path: EDN Asia >> News Centre >> Industrial/Mil/Aero >> 'Invisibility cloak' against sound waves and sonars
Industrial/Mil/Aero Share print

'Invisibility cloak' against sound waves and sonars

19 Mar 2014  | Julien Happich

Share this page with your friends

Professor Cummer thinks this is the sort of tricks that can be done with this approach. "I am trying to engage as many audio design professionals as I can to explore these possibilities. It's not really my area so I don't have a good sense of what would or would not be useful, but I am fairly certain that there must be useful things that can be done this way."

Of course, another obvious application that one would think of is stealth submarines.

"We conducted our tests in the air, but sound waves behave similarly underwater, so one obvious potential use is sonar avoidance," admits Cummer whose research was supported by Multidisciplinary University Research Initiative grants from the Office of Naval Research and from the Army Research Office.

"There are major challenges with implementing the same approach in water. Air is much easier, which is why we did that first. But we are thinking about water."

But to what extent could this cloak be adapted to various shapes and does any specific shape of the cloak require specific computing with regard to the direction from which the sound comes?

"Interestingly, the underlying theory says that you can design a cloak of any shape that works for sound coming from all possible directions," answers Cummer.

"A sphere has nice symmetry that makes it easier to design, but a cube is possible too. However, the parameters of the material you need for the cloaking shell (for acoustics, these are effective mass density and effective stiffness) depend critically on the shape. This cloaking concept could be adapted to other shapes, but they would have to be reengineered and re-fabricated," he added.

In fact, the cloaking shell has to have significant thickness to it in order to guide the acoustic wave energy. It could be designed thinner but then it becomes very hard to make if it is much more than about 10 times thinner than the size of the object it is hiding, according to Cummer.

This limitation makes it impractical to use such metamaterials as a "skin," for example, to make stealth submarines. However, one of the easiest shapes to craft for an acoustic cloak, the pyramid shape, could be built as nuclear submarine hide-out as long as it would be large enough for the sub to fit inside.

Could these metamaterials be conceived as re-shapable, re-configurable MEMS skins controlled by software to adapt the cloak to specific situations?

"That is way, way down the road, but there's no fundamental reason that it couldn't be done, provided access to computer-controlled reconfigurable-shape materials," concluded Cummer.

 First Page Previous Page 1 • 2

Want to more of this to be delivered to you for FREE?

Subscribe to EDN Asia alerts and receive the latest design ideas and product news in your inbox.

Got to make sure you're not a robot. Please enter the code displayed on the right.

Time to activate your subscription - it's easy!

We have sent an activate request to your registerd e-email. Simply click on the link to activate your subscription.

We're doing this to protect your privacy and ensure you successfully receive your e-mail alerts.

Add New Comment
Visitor (To avoid code verification, simply login or register with us. It is fast and free!)
*Verify code:
Tech Impact

Regional Roundup
Control this smart glass with the blink of an eye
K-Glass 2 detects users' eye movements to point the cursor to recognise computer icons or objects in the Internet, and uses winks for commands. The researchers call this interface the "i-Mouse."

GlobalFoundries extends grants to Singapore students
ARM, Tencent Games team up to improve mobile gaming

News | Products | Design Features | Regional Roundup | Tech Impact