Scientists Bounce Around Bulletproof Ideas


September 16, 2003, 05:17 PM,1406,KNS_359_2258475,00.html

Scientists bounce around bulletproof ideas
September 15, 2003

Oak Ridge National Laboratory scientists have come up with a ceramic armor that appears to surpass commercially available packages in stopping armor-piercing projectiles.

Steve Nunn, a senior researcher in the Metals and Ceramics Division, said it's not clear why tiles of boron carbide ceramic made at ORNL outperformed similar materials on the market.

"That's hard to say because the commercial stuff that's out there is processed by proprietary methods,'' Nunn said. "We really don't know what they add or exactly how it's processed.''

In ballistics tests at the government's Oak Ridge firing range, a ceramic tile fabricated at ORNL was able to stop a projectile at 24 percent higher velocity than one type of commercially available armor. It was 11 percent better than ceramic armor from another supplier.

The hardness of the ceramic helps to fracture the bullet, breaking it up into smaller fragments.

When a tile of boron carbide ceramic was sandwiched with sheets of a polymer matrix composite, it was able to stop a 30-caliber armor-piercing bullet traveling at speeds up to 2,800 feet per second.

The polymer absorbs energy and seems to enhance the capabilities of the ceramic tile, Nunn said, although researchers don't fully understand why.

Scientists have experimented by adding thin layers of other protective materials such as Kevlar and Spectra Shield Plus. The spall cover on the front of the tile helps block ricocheting fragments, and the backing serves as a "catcher's mitt'' for whatever gets through the ceramic tile.

There's still much room for improvement, said Nunn, 53, who holds a doctorate in materials science and engineering from the University of Michigan.

"We haven't even come close to optimizing this,'' he said. "This was a relatively small project.''

Initial funding from the U.S. Army is gone, and the ORNL researchers hope to acquire new money to expand the effort.

Nunn, who came to Oak Ridge 12 years ago after working at Sandia National Laboratories and General Electric, said there seems to be a lot of interest in ORNL's work with boron carbide ceramic and other materials.

"We've had a lot of people come in from the military and commercial people who are doing things for the military,'' he said. "We've given I don't know how many presentations.''

Currently, the military uses armor made of boron carbide ceramic for the exterior of some helicopters, as well as for the structure of their crew seats. In addition, it is used on some commercial aircraft to help contain auxiliary power units in case of an explosion or other problem.

"It is one of the lightest ceramics,'' Nunn said, explaining why it could be of potential use for soldier vests or other personnel protection.

The material also could be fabricated into armor for limousines and all types of military vehicles, he said.

The Oak Ridge research team wants to perform additional lab tests to understand why the ORNL material has better properties than comparable ceramics and to try to maximize the use of those properties.

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4v50 Gary
September 16, 2003, 05:49 PM
Article needs to be rewritten and made to read that you could go to Home Depot or Lowe's, pick up a flower pot, wear it and be bullet proof. :D

El Tejon
September 16, 2003, 06:14 PM
Justin, didn't some techno geek, er, I mean Purdue professor of engineering win an award for this stuff last year???:confused:

September 17, 2003, 01:46 AM
I've no idea, though it certainly wouldn't surprise me. There's all kinds of neato science stuff going on in the labs of Purdue.

September 17, 2003, 03:40 AM
There's some pretty neato science stuff goin' on out at Oak Ridge, too, if the six-legged whitetail in the local woods are any indication. ;)

El Tejon
September 17, 2003, 08:24 AM
Tamara, yeah, but in Oak Ridge it's all football related.:D I read that scientists there have developed the perfect football, to be deployed to Knoxville at once.:p

September 17, 2003, 08:44 AM
Wouldn't ceramic armor be worthless after one hit? It shatters to stop one bullet, the next just comes right on through, right?

Mark Tyson
September 17, 2003, 09:22 AM
Ceramic armor is not your usual flower pot material - it's a composite. Yes, cracks and fractures are a problem - the same properties that cause the ceramic to crack are what gives it its protective value. However, there's a couple of ways they overcome this. What they used to do was use a tile mosaic design when building the inserts. This reduced but didn't eliminate cracking. It was also heavy. Now they're trying to design better composite materials through microengineering to reduce weight and reduce cracking.

September 17, 2003, 09:36 AM
This is an idea as old as bullet-resistant glass (an older idea than some would believe).
Sandwich layers of hard but brittle material (ceramic or glass) between layers of a tough, stretchable polymer (or steel armor, in the case of tanks) and adhere them very securely. Repeat until it will stop the bullet you want to stop. The ceramic does most of the stopping, and the plastic keeps your sandwich together, as well as doing some to help stop cracks in the ceramic (or at least keeping the cracked ceramic on the plate where it will do some good).
Better polymers, better ceramics, better methods of smashing them together = better armor.

Most ceramic threat plates today aren't designed this way (cost of production being the primary reason, I think), but the idea itself - good as it is - isn't all that original.

September 17, 2003, 11:01 AM
On the LOTR DVD theres a mini documentary on the arms and armor of Middle Earth.

They used old age forging techniques to make the blades authenic, but did not want to replace brittle, hardened swords on a daily basis. The solution was to fill the hilts with
polyurethane. The shock was absorbed by the rubber, and they only broke one during the filming.

I would think if NASA worked on a punkin chunkin machine, ( they would obtain gourd escape velocities. Of course, to keep the squash together, they would also splice boron fiber making genes into the vegetable projectiles plant. And thus, the organic threat plate is grown.


Double Naught Spy
September 17, 2003, 11:47 AM
cordex hit the nail on the head. While the ceramic may break, being incased/sandwiched keeps it all together. Ballistic ceramic plates are already in used, usually covered by materials such as kevlar, spectra, or some other flexible polymer.

As for being shot once and being worthless, the ceramic may break but won't be shattering to dust expect at the point of impact. So ideally, it will handle more than one hit.

Keep in mind also that regular soft body armor is rated for 3 hits by NIJ, or it used to be. It may or may not work well beyond that amount of damage and the real problem is where the multiple hits pull or shred the fabric in the surrounding space and hence weaken a larger area than just where the material was impacted. From what I have seen, they will last for many hits, assuming they are closely spaced.

Ceramic, steel, or soft armor, after one hit and end of hostility, the materials should be considered compromised and replaced.

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