Army scientists, engineers develop liquid body armor

[Kharn]

Army Times source link

Army scientists, engineers develop liquid body armor

By Tonya Johnson
Kevlar fabric with shear thickening fluid, after impact by a fragment simulating projectile.

ABERDEEN PROVING GROUND, Md. (Army News Service, April 21, 2004) -- Liquid armor for Kevlar vests is one of the newest technologies being developed at the U.S. Army Research Laboratory to save Soldiers' lives.

This type of body armor is light and flexible, which allows soldiers to be more mobile and won’t hinder an individual from running or aiming his or her weapon.

The key component of liquid armor is a shear thickening fluid. STF is composed of hard particles suspended in a liquid. The liquid, polyethylene glycol, is non-toxic, and can withstand a wide range of temperatures. Hard, nano-particles of silica are the other components of STF. This combination of flowable and hard components results in a material with unusual properties.

“During normal handling, the STF is very deformable and flows like a liquid. However, once a bullet or frag hits the vest, it transitions to a rigid material, which prevents the projectile from penetrating the Soldier’s body,†said Dr. Eric Wetzel, a mechanical engineer from the Weapons and Materials Research Directorate who heads the project team.

To make liquid armor, STF is soaked into all layers of the Kevlar vest. The Kevlar fabric holds the STF in place, and also helps to stop the bullet. The saturated fabric can be soaked, draped, and sewn just like any other fabric.

Wetzel and his team have been working on this technology with Dr. Norman J. Wagner and his students from the University of Delaware for three years.

“The goal of the technology is to create a new material that is low cost and lightweight which offers equivalent or superior ballistic properties as compared to current Kevlar fabric, but has more flexibility and less thickness,†said Wetzel. “This technology has a lot of potential.â€

Liquid armor is still undergoing laboratory tests, but Wetzel is enthusiastic about other applications that the technology might be applied to.

“The sky’s the limit,†said Wetzel. “We would first like to put this material in a soldier’s sleeves and pants, areas that aren’t protected by ballistic vests but need to remain flexible. We could also use this material for bomb blankets, to cover suspicious packages or unexploded ordnance. Liquid armor could even be applied to jump boots, so that they would stiffen during impact to support Soldiers' ankles.â€

In addition to saving Soldiers' lives, Wetzel said liquid armor in Kevlar vests could help those who work in law enforcement.

“Prison guards and police officers could also benefit from this technology,†said Wetzel. “Liquid armor is much more stab resistant than conventional body armor. This capability is especially important for prison guards, who are most often attacked with handmade sharp weapons.â€

For their work on liquid armor, Wetzel and his team were awarded the 2002 Paul A. Siple Award, the Army’s highest award for scientific achievement, at the Army Science Conference.

(Editor’s note: Tonya Johnson is a member of the Army Research Laboratory Public Affairs Office.)

Kevlar fabric with shear thickening fluid, after impact by a fragment simulating projectile.

I thought this was interesting, but then I'm biased: Prof. Wagner taught my Thermodynamics I and Heat & Mass Transfer classes and two of my good friends are the undergrads doing the experiments with the gun at Aberdeen (as its not allowed on University property). I'll have to get the mass/velocity spec from them for the projectile, but it's a NATO standard/specification for testing body armor.

Kharn

 

[k8ysv]

That's pretty neat! I wonder if it's anything like this stuff:
http://www.thinkgeek.com/cubegoodies/toys/5ac8/
I've got some of it and it's amazing. Kinda like silly putty, but one of its properties makes it rock solid under a sharp impact. This stuff will actually ooze and flow like a putty, but shatter if you hit it with a hammer. Then you just mush all the pieces back together.

 

[Zedicus]

You can get a Simmalar Effect by mixing starch powder with just enough water to make it moist.

 

[hksw]

How much more is this going to weigh? (Fluids, particularly filled non-Newtonians, being much more weighty than fabric.) I guess it couldn't weigh more than a ceramic plate.

 

[PATH]

Looks promising and has the potential if perfected of saving many lives.
Liquid body armor before was a mental state induced by copious quantities of alcohol!

 

[p35]

My kids like to do this with corn starch, food coloring, and water. Pretty interesting stuff to fool with.

 

[MagKnightX]

Does anybody remember when the Dilbert website had that massive idea-exchange area? I had posted about fluid body armor way back then. They stole my idea!

 

[Penforhire]

Very cool concept. There are plenty of viscoelastic materials that have this property but I didn't know any had this severe a change from soft to hard.

 

[Henry Bowman]

What if you made projectiles (bullets) out of this stuff? May need to have a thin shell to contain it. Density would be less than lead. But I wonder how it would react to striking a hard or soft surface. Would it be very penetrating and then melt away after impact?

 

[Correia]

That is really really neat. Just imagine bullet resistant BDUs. Wow.

 

[Heraclitus]

The liquid, polyethylene glycol, is non-toxic, and can withstand a wide range of temperatures. Hard, nano-particles of silica are the other components of STF.

You mean that all this time I could have soaked my Bratari in anti-freeze, rubbed it in the sand, and I'd be ready for combat? Awesome!

 

[DadOfThree]

Tons of civilian uses. Imagine how much quicker the agile the NFL players could be without the bulk of the pads.

 

[Bravo11]

"Fluids, particularly filled non-Newtonians"

That is just what I was going to say.....NOT.

 

[bluecowdawg]

blah,blah,blah

instead of our wonderful thoughtful government spending our tax $$$$$ on this they should spend the money on providing our soldiers,"DEFENDERS OF OUR FREEDOM", with the body armor that already exsists. cause no matter how good it may be , it is no good if it is not issued to our fighting forces , i say this because i read on some forum where the parents of some of the troops are spending their own money to send armor to their son,s and daughter's in iraq

 

[Diggler]

Uh, will the really slow bullets now be the 'armor piercing' kind?

What if you're getting stabbed? Does the perp have to S-L-O-W-L-Y push the knife into you?

Weird.

 

[Steve Smith]

"The slow blade penetrates the shield" -Gurney Hallek, Dune

 

[2nd Amendment]

Hmm, interesting. I remember in the late 80's having a leather jacket from BMW which had certain hi-impact areas, elbows, upper back, etc protected by a material/system that was supposed to do the exact same thing. Hardened on impact to absorb shock and prevent road rash after leaving one's scoot at unexpected times and high velocities. I never cared to actually test it's efficiency.

 

[atek3]

hey steve, i was thinking the same thing

atek3

 

[Don Gwinn]

Steve, exactly what I thought. Holtzmann lives.

 

[tcsd1236]

instead of our wonderful thoughtful government spending our tax $$$$$ on this they should spend the money on providing our soldiers,"DEFENDERS OF OUR FREEDOM", with the body armor that already exsists. cause no matter how good it may be , it is no good if it is not issued to our fighting forces , i say this because i read on some forum where the parents of some of the troops are spending their own money to send armor to their son,s and daughter's in iraq

While the current armor needs to be provided in adequate levels, R & D needs to continue or there would be NO improvements coming out in the future.

 

[Matt G]

Precisely. Another nifty thing about this technology is that it may actually make it cheaper to get armor to our front-line guys. Also, while it's nice to bring GI Joe home alive, with armored sleeves, he may actually come home in one piece! With armored shirttails, he may actually manage to avoid carrying a colostomy bag with him the rest of his days. R&D is a good thing. W/out R&D, our troops would have NO body armor, trapdoor springfields (or muzzle-loaders), single-shot pistols, no tanks. . .

Also, I rather gather that this is the culmination of research that started years ago. (Note that they just NOW won a 2002 award for scientific excellence.) Sometimes it takes a while for word to get out. I'm mildly surprised that it was even allowed to get out, in this instance.

How much more is this going to weigh? (Fluids, particularly filled non-Newtonians, being much more weighty than fabric.)

Sure, fluids are weightier than fabric, but Kevlar is a pretty dense fabric. Also, what's so weighty about water saturated with corn starch (the most common example of a non-Newtonian fluid I know of)? For a good example of what a NNF can do, mix up a gallon of cold water with a package of cornstarch in a large punch bowl or mixing bowl, so that it has the texture of medium pancake batter. Take a ladle or spatula, and SLAM it down into the slurry, hard! If this were like water or a normal fluid, you'd have a mess. But the starch slurry won't splatter! It's counter-intuitive. You'll expect it to go everywhere, but it just slowly absorbs the slowed-down ladle.

I saw it on Mr. Wizard.

Silly Putty's a cool example of a Non-Newtonian Solid.

 

[Nightcrawler]

A thought.

Say armor like this becomes common and all the major armies adopt it. It's developed to the point where a standard soldier's loadout includes a lightweight vest that'll stop 7.62x51 or 7.62x54 armor piercing ammo, even at point blank range.

What'll we do for small arms? Start working on new ammo that has even better penetration, or more powerful rifles that can defeat the vests? Be an interesting arms race, in any case.

 

[Matt G]

I doubt it would make that big a difference. I've never seen the numbers, but I gather that a great number of the casualties saved by body armor in warzones is from shrapnel/flak/fragments from grenades, RPG's, shells, mines, etc. Add in the occasional vehicle wreck or fall in which body armor saves the day, probably without a credit. Then there's that nasty habit that seems to be developing among protestor factions to strap a bunch of explosives to someone and walk up to a checkpoint, or else put a carbomb at such a congregation point. I realize shock/blastwaves go through fabric, but the stuff they push into a man can be stopped.


Pity the poor GI, though, who will be ordered to don this stuff from head to toe, in such unpleasant climes. It is already a testiment to the discipline of our military that the Iraqis have a die-hard rumour going around that our GI's armour is air-conditioned. Clearly, that must be the answer-- no man could bring himself to wear it under 120+ degree sun!

 

[El Tejon]

Devil Doggies will be wearing puntees and "leathernecks" again!

 

[Kharn]

I finally talked to my classmate:
The test projectile is a "22 cal FSP" (he doesnt recall the weight off-hand, but its a NATO standard, not just a .22lr slug) and the velocities are varied between 800 to 2000 fps, but their targets are only five layers of kevlar. Normal vests are >20 layers thick, so its not hard to figure out this will stop some serious stuff.

The vests will weigh the same in the end, as they remove some kevlar layers to balance out the weight of the added fluid, but protection is increased substantially.

Kharn