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Mantis shrimp may hold the secret to lighter, tougher body armors


June 9, 2012

The study of this marine crustacean may lead to lighter and more resistant materials that ...

The study of this marine crustacean may lead to lighter and more resistant materials that could be used in military applications (Mantis Shrimp photo via Shutterstock)

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The mantis shrimp is a fascinating creature that has the ability to punch its prey into submission with a club that accelerates underwater at around 10,400 g (102,000 m/s2). By studying the secrets behind this formidable weapon, a Californian researcher hopes to develop an innovative, hi-tech material that is one third the weight and thickness of existing body armor.

Some animals are very poorly named: the flying lemur can't fly and is not a lemur, the rabid wolf spider is as placid and innocuous as spiders come, and the jackass penguin gets along just fine with its peers.

The mantis shrimp fits in this category - it is neither a mantis nor a shrimp. It lives a solitary life, displays very aggressive behavior, and, most importantly, packs a mean punch. So mean, in fact, that its "fist" can go from 0 to 50 mph (0 to 80 km/h) in just three thousands of a second, underwater. As it accelerates the club creates a pressure wave so strong that it instantly boils the water in front of it and even generates tiny flashes of light before striking its target with the force of a speeding bullet.

The animal needs to be kept in special aquariums so it won't break the glass. This video gives a sense for just how powerful its strike can be.

The mantis shrimp uses its formidable weapon to break the shells of its prey but, until recently, it was unclear how its club could receive such a severe, repetitive pounding without suffering too much damage. The club, in fact, handles as many as fifty thousands strikes during its lifespan. So how does it maintain structural integrity? Assistant professor David Kisailus from the University of California, Riverside set out to find an answer.

The club, Kisailus found, is a highly complex structure comprised of three highly specialized regions working together to create a structure tougher than many engineered ceramics.

The impact area is one millimeter thick and contains a high concentration of mineral similar to that found in human bone, except that the crystals that compose it are aligned perpendicularly to the surface of the strike to minimize cracks.

Further inside, highly organized layers of chitin fibers act as shock absorbers. The fibers are arranged in a helical structure to slow down the spreading of cracks. Here's the trick: the helix forces the cracks to constantly change direction, which disperses their energy and quickly stops them from propagating.

The helicoidal structure in the mantis shrimp's club stops the propagation of cracks (Imag...
The helicoidal structure in the mantis shrimp's club stops the propagation of cracks (Image: Kisailus Lab/UCR)

Finally, the club is encapsulated on its sides by chitin fibers that wrap around the club, keeping it intact – much like a boxer who places tape around their fists.

A comprehensive study of the nature of the microscopic structure of the mantis shrimp's club appeared in a recent issue of the journal Science.

Source: UCR

About the Author
Dario Borghino Dario studied software engineering at the Polytechnic University of Turin. When he isn't writing for Gizmag he is usually traveling the world on a whim, working on an AI-guided automated trading system, or chasing his dream to become the next European thumbwrestling champion.   All articles by Dario Borghino

A thousand or million of these synthetic clubs would generate enough kinetic force to produce electricity; either by steam or mechanical piezoelectric. If duplicated on a nano scale. Would it be energy efficient?

Robert Burke
10th June, 2012 @ 04:46 pm PDT

if you have ever been to the seafood restaurants on Hong Kong's Lamma island you'll also know that mantis shrimp grow to the size of a small lobster and are delicious when deep fried.

11th June, 2012 @ 09:26 am PDT

We can do a similar thing with our finger and thumb. By holding back a finger with our thumb we can 'flick', for example, a marble clear across the room. The finger nail doesn't provide the same protection as the mantis shrimp enjoys, so when someone flicks they don't want to have any air gap between their finger nail and the projectile.

11th June, 2012 @ 12:06 pm PDT

Not an everyday design but it sure is a remarkable species.

Shawn Powell
11th June, 2012 @ 01:42 pm PDT

How about crash helmets and crash barriers, this could be huge.

11th June, 2012 @ 05:37 pm PDT

100,000 m/s- B. S. That's about 1/3 the speed of light- though relativistic effects wouldn't be significant, the kinetic energy in such a strike (assuming a 1 gm punching claw, though I bet the claw is more massive) would be enormous at 5,000,000 joules!. I suspect they meant to write 100,000x g.

John J. Peloquin
11th June, 2012 @ 05:57 pm PDT

No actually, that's not even close to the speed of light, which happens to be 300,000 kilometres per second. Which would make this 3,000 times slower, in fact. Sorry, but the article's statistics are quite correct.

Danny Allman
14th June, 2012 @ 09:31 am PDT

To those people commenting about 102,000m/s^2, please notice that it is a measure of rate of acceleration.

If the animal would keep on accelerating it's club at the same rate for more than the three thousandths of a second that it does, like for a whole second. Then it would reach 102,000m/s (extremely unlikely, especially underwater)

Roni Olavi Wilhelm Eskola
19th June, 2012 @ 06:15 am PDT

Furthermore, final speed of 50 mph is hardly a speeding bullet.

19th June, 2012 @ 12:28 pm PDT

@grunchy, you have misread the article. it refers to acceleration from 0 to 50 mph in 1/3000s AND underwater....this is VERY impressive

Zgabearta Iftode
22nd June, 2012 @ 03:04 pm PDT

That's 102,000 m/s^2 . Note the "^2" part. The same as m/s/s . That's an acceleration, not a final speed.

Since the strike only lasts 3 milliseconds (0.003 s), the speed of the club is as stated, around 50mph at contact.

Brian H
4th July, 2012 @ 06:45 pm PDT

Zga, you misread it, too. It's not 1/3000, it's 3/1000. That's 9x slower. ;)

Brian H
4th July, 2012 @ 06:50 pm PDT
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