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Small Blast-proof glass panel after test  (Source: DHS S&T)
Inventin may lood to better looking Popemobile

High profile leaders and government buildings all around the world can be targets of terrorist attacks at any given moment. Many of these officials and buildings are protected with defenses that are designed to protect the people inside buildings and vehicles. One of the more common types of protection is glass that is both bullet and bomb resistant.

According to the Pentagon, glass shards are one of the leading causes of death in many bombing attacks. The problem with the blast-resistant glass on the market today is that the material is very thick and can’t fit into the windowpanes in existing buildings. The glass is said to be about as thick as a 300-page novel.

A team of engineers from the University of Missouri and the University of Sydney in Australia has developed a new type of blast-resistant glass that is much thinner than the current glass, but has the same blast-resistant properties as the thick stuff. The new glass is about a quarter-inch thick and is made from a plastic composite with an inert layer of polymer reinforced with glass fibers. The team testing the glass has already exposed a small test panel to an explosion.

Sanjeev Khanna, the project's principal investigator and an associate professor of mechanical engineering at Missouri said, "The results were fantastic. While the discharge left the pane cracked, the front surface remained completely intact."

The new glass gets its strength from the use of long glass fibers in a woven cloth that is soaked in liquid plastic and then bonded with adhesive. The resulting glass is very strong, thin, and clear. The current thick blast-resistant glass has a green tinge.

The new glass would also fit existing windowpanes.

"Designing an affordable, easy-to-install blast-resistant window could encourage widespread use in civilian structures, thereby protecting the lives of occupants against multiple threats and hazards," notes John Fortune, manager of the project for the Infrastructure and Geophysical Division at S&T.

Tests with larger explosions and larger glass sheets are planned.



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RE: Other uses?
By Solandri on 12/10/2010 2:53:34 PM , Rating: 3
quote:
I was going to say, if they can get this stuff cheap enough, any physics people want to chime in on how this might do in say, a tornado? Glass is such a brittle part of a building right now, you would think that if they could make it more stable and less dangerous (dangerous in extreme conditions at least), this could be huge.

Actually, you want the windows to pop out in a tornado. That's what's called a controlled failure - a component of the structure is designed to fail first in order to protect the rest of the structure. Without the windows blowing out, you can get a more destructive event, like the roof popping off.

Here's a similar design on the Southwest Airlines plane which depressurized last year:
http://aviationblog.dallasnews.com/archives/2009/0...
The panel was deliberately designed with a weak ring whose sole purpose was to fail before the rest of the panel. When a fracture developed within the panel (part of the skin of the aircraft), it spread, until it hit this weak ring, at which point the ring blew out. The plane depressurized, but the damage was contained to the area within the ring. If you don't design such failure modes into your structure, the fracture could spread along the entire panel, "unzipping" the skin of the aircraft and resulting in a much more catastrophic failure. Like what happened to Aloha 243:
http://www.aviationchatter.com/wp-content/uploads/...

The main problem with glass windows is that they shatter into sharp shards. Tempered glass and plexiglass which avoid this have been available for decades, but their cost is high enough that it's cheaper to just replace the glass in the few cases where it does shatter and pay for any consequential medical bills. Even in California where a large number of windows break during an earthquake, people still go with regular glass and replace it if it does break. I sincerely doubt this new glass is cheaper than tempered glass or plexiglass, so I don't see it being any more successful than those two at replacing regular glass.


RE: Other uses?
By makken on 12/11/2010 12:08:54 AM , Rating: 2
^This.

As I understand it, in a tornado, you have high winds over the top of your roof. If your windows hold, the air under your roof is stationary, creating a pressure differential that can literally pop off your roof. If your windows pop, however, you have air flowing both above and below your roof, lessening the pressure differential, and potentially saving your roof.

see: http://en.wikipedia.org/wiki/Bernoulli%27s_princip...
and: http://en.wikipedia.org/wiki/Lift_force


RE: Other uses?
By goku on 12/16/2010 3:36:52 PM , Rating: 2
plexiglass shatters btw.. I think you mean lexan. But plastic scratches too easily so it depends on the application but for longevity, a tempered glass solution would be best.


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