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Flexible Body Armor
dotmax writes "One item to pop out of the Turin Winter Olympics is the use of flexible body armor. Similar to silly putty, this shear rate material is flexible under normal load and hardens under impact. Sounds expensive, but could offer some great alternatives for traditional hard shelled impact gear in active sports and military applications."
The original bullet-resistant vest was flexible. It was made of powdered glass, flexible until hit hard, at which point it would stiffen up and spread the force of the impact.
-russ
Don't piss off The Angry Economist
Having rigid plates even on parts of the body that flex less is bulky and cumbersome. Flexible armour is a great concept - far less noticable in normal conditions than some of the rigid ski body armour solutions e.g. Dainese
BTW For the pseudo science and some nice pictures of 'molecules' see the 3DO website
Ever wear shin pads or arm protectors? Ever notice that they need to be strapped on and chafe like a SOB? I'd love to get my hands on something like this. Built into an undersuit, moves with you, no staps, lightweight and instant protection when you hit something. I'd like to know that my non-moving bones (shins, radius/ulna, skull) were wrapped in protection when the jerk in an SUV cuts in front of my motorcycle and takes me down.
FWIW, this stuff sounds like what happens to a semi-liquid mix of cornstarch and water. Slide your hand in and it drops into the fluid; hit it hard and no penetration at all.
For body armor purpses: .0004 (four ten-thousands) of an inch into me. In the same time the armor hardens in an circle with a radius of .0004in (For the sake of arguement a very thin bullet). In the next millionth of a second the bullet travels an additional .0004 of an inch into the target. The armor now also has a circle of .0008in in diameter. The affected area starts to grow rather quickly.
The material's reaction time is probably related to how fast the shock-wave of the hit travels through the material. For the sake of arguement: The of the impact shockwave travels through the suit at the same speed sounds travels in water (sound is a shockwave). So it travels roughly 1482 m/s. So the shockwave would take roughly 0.0001 seconds to travel across my entire chest. Modern bullets can travel roughly the same speeds. In that same 0.0001 seconds a bullet would be several inches behind me.
So here comes the messy part: Can this kind of stuff protect a person from gunfire?
So a bullet hits a person wearing this stuff. In the first 10^-6 of a second the bullet travels
Time Depth/Shockwave Area Affected
0.000050: 0.2000: 0.1256637061
0.000100: 0.4000: 0.5026548246
0.000150: 0.6000: 1.1309733553
0.000200: 0.8000: 2.0106192983
0.000250: 1.0000: 3.1415926536
0.000300: 1.2000: 4.5238934212
0.000350: 1.4000: 6.1575216010
0.000400: 1.6000: 8.0424771932
0.000450: 1.8000: 10.1787601976
In the time it takes the bullet to travel 1 inch into the body enough of the armor has hardened to cover 3 square inches of the target's body. Now the bullet has to deform or move that much more material in order to continue its trip in. Most likely the person could end up with a weird dent in their body where the bullet hit. This is of course dependant upon when the material fails and stops giving protection and how fast the shockwave travels through the material.
Considering that though: I'd rather have a dent in my body then a hole.
Currently the ski suits are used to protect against impacts against relatively flexible things at speeds above sixty miles per hour. So for the athletes to approve of it, it has to work pretty quickly and revert pretty quickly. You are in contact with gates for hundredths of a second and if the armor/fluid reacts fast enough for the athletes to notice and approve, you know the army is going to buy a suit and shoot at it to see what the results are going to be. Imagine the next round of (Disposable) ceramic armor plates that is sent to the troops in Iraq is coated in that stuff and it improves survivability.
Hell, coat the inside of the flak vests in the stuff and have it sent to the firing range for testing. The army always loves things that do the following: improved force protection with less weight. While the army is a giant monolithic beuracracy it does actually get things done once in a while.
Architectural plans are like computer source code with a couple of differences: You only compile once.
Hopefully this stuff brings us back to sword fights ala Dune.
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WHO ATE MY BREAKFAST PANTS?
So you cover this stuff with a material that doesn't wear away easily. Like Kevlar.