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http://knoxnews.com/kns/news_columnists/article/0,1406,KNS_359_2258475,00.html
Scientists bounce around bulletproof ideas
By FRANK MUNGER
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.
Scientists bounce around bulletproof ideas
By FRANK MUNGER
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.
