Liquid Armor

[Guest guest]

Liquid Armor

 

http://www.sciencentral.com/articles/view.php3?type=article & article_id=218392807

 

 

06.15.06 email to a friend

 

 

 

Video

 

 

 

 

(movie will open in a separate window)

Choose your format:

 

Quicktime

 

Realmedia

 

 

Flexible

full-body protection that could save our troops' lives and limbs is at

the top of the list for many researchers and technology companies. One

such product could soon make its way to Iraq. As this ScienCentral News

video explains, the secret ingredient is a liquid that could turn

lightweight material into full-body armor. Full Liquid Jacket

The

current war in Iraq is leaving behind a legacy of wounded soldiers. For

every fatality there have been between seven or eight injured -- a

number amounting to 18,356 as of June 11, 2006 (U.S. Department of Defense).

That's a higher ratio of injured to dead than in any previous American

war, a mixed blessing that can largely be attributed to advances in

body armor and improved battlefield medical treatment. A

new " liquid armor " could be the solution for protecting the parts of

the body that aren't currently covered by standard-issue ballistic

vests – arms and legs, where many of these devastating and

life-threatening injuries occur. Co-developed by two research teams –

one led by Norman Wagner at the University of Delaware

, and the other led by Eric Wetzel at the U.S. Army Research Lab in Aberdeen, MD – the liquid technology will soon lead to light, flexible full-body armor.

 

The liquid - called shear thickening fluid

is actually a mixture of hard nanoparticles

and nonevaporating liquid. It flows normally under low-energy

conditions, but when agitated or hit with an impact it stiffens and

behaves like a solid. This temporary stiffening occurs less than a

millisecond after impact, and is caused by the nanoparticles forming

tiny clusters inside the fluid. " The particles jam up forming a log jam

structure that prevents things from penetrating through them, " Wagner

explains.Wagner and Wetzel developed a way to specially treat ballistic fabrics, such as

Kevlar, with the liquid, making them dramatically more resistant to puncture and much better at reducing blunt trauma.

" We

integrate those materials with the fabric itself, imbibe it in a way,

such that the shear thickening fluid is not at all evident, it's not a

coating on the outside. It's actually intercalated directly into the

material, " says Wagner. The

stiffening of the liquid allows the energy of an impact to be

distributed over a much larger surface area – so the force, rather than

being focused on the area of a bullet head, is distributed over the

area of the surrounding fabric. Ballistic tests have demonstrated that

the treatment can actually prevent bullets from penetrating.The

treated Kevlar is even better at resisting puncture from sharp

projectiles, such as knife stabs or shrapnel from roadside bombs. As

Wagner explains, Kevlar was never designed to function against puncture.

" Bullet

proof vests and Kevlar are not very good against stab threats like

puncture that you might see in correctional prison guards or from

fragmentation threats on the battlefield, " he says.The

treatment of the fabric prevents the fibers from spreading apart or

" windowing, " which keeps sharp objects from entering. That means that

not only would materials treated with shear thickening fluids be better

against conventional threats such as bullets, but would also resist

puncture from shrapnel. The materials would also remain light – only 20

percent heavier after treatment - and flexible, which means they could

be used for much-needed protection of the limbs.

" We can make thin layers of material for use on the arms and legs that

remain flexible under normal motion, but become rigid and absorb energy

when impacted by a ballistic threat or a knife, " Wagner says.U.S. manufacturer

Armor Holdings recently licensed the technology and plans to release its first products by the end of the year.Wagner

says there could also be many civilian applications – like protecting

people during car crashes, or making tires sturdier. Some of Wagner's recent work was published in the May/June 2005 issue of the Journal of Rheology and was featured in the May 2006 issue of

Scientific American. For a complete list of publications see Dr. Wagner's website.

Some of the funding sources included IFPRI and the Army Research

Laboratory CMT program through the Center for Composite Materials of

the University of Delaware as well as the NASA Delaware Space Grant College and Fellowship Program

..

 

 

top

email to a friend

by Eva Gladek