UNBREAKABLE bendy phone screens built, thanks to SHELLFISH Engineers have borrowed a technique from shellfish to build a pre-stressed form of glass that can bend rather than break. As anyone who has dropped their phone from a height knows, glass has a tendency to fracture when struck. But boffins at McGill University's department of mechanical engineering have developed a new form of …
I used to work in a bullet-proof glass factory. The secret (apart from being quite thick) was that we laminated in lots of thin soft vinyl layers under vacuum, they would stop the crack propagation whilst the glass itself provided the resistance to projectiles. Doing this across the whole structure in 3D, not just 2D lamination sounds like genius. I'd buy one.
(Sent from my £600 phone with a starfish crack in the bottom right hand corner which I've had to protect with clear epoxy resin)
There are a number of transparent armor architectures. Those used in vehicles tend to be alternating layers of glass (or SiAlON, or sapphire) and polymer. The glass is a hard surface that blunts and fragments a projectile, while the polymer provides a means of soaking the bullet's energy (primarily through delamination between the glass and polymer - it takes energy to peel the layers apart).
Plain polycarbonate and other polymers tend to be too soft to stop rifle-caliber and larger bullets, for all their fantastic strength. Hence, hard surfaces are often added. This applies to body armor, too. While armor vests meant to halt pistol bullets rarely include hard surfaces, it's easier (and thinner) to add a ceramic or steel plate if you want any chance of stopping rifle bullets. The hard plate blunts and fragments the bullet, while the Kevlar (or equivalent) polymer vest behind it acts like a catchers mitt for the remainder.
I have seen a pure polymer armor transparency that could stop a .44 Magnum (insert Dirty Harry references). A former boss kept it, and the embedded bullet, on his desk. However, it was about 5 to 6 centimeters thick. And a .44M pistol round isn't nearly as challenging to stop as a rifle bullet.
Basically what Cray says. Our panels would stop a 9mm rifle bullet at 1m, the first save was guaranteed, tested, all ISO9000-ed etc. Second round stood a chance at getting through, but by that point you've had the warning and taken some action.
At our factory we also used to do Concorde and jumbo jet windscreens, popemobile, specialist helicopter shaped panels etc. Lots of very skilled hand-work, some panels were worth tens of thousands of pounds with vapour deposited gold UV protection and embedded heating elements etc. We also did the windows for the intercity HST sets, all tested and demonstrably significantly more resistant to high-speed projectiles than the train body surrounding it.
Bird tests for jet canopies were real, the frozen chicken myth was just that, it was alive until about 5 minutes before it was atomised all over the high intensity lamps for the high speed filming.
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