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Liquid Armor the New Bulletproof Vest
kjh1 writes "Armor Holdings Inc. plans to start selling their 'liquid armor' next year. The new armor, originally envisioned to be spread on like peanut butter, is instead sprayed onto Kevlar in ultrathin coats. From the article: 'it's a mix of polyethylene glycol, a polymer found in laxatives and other consumer products, and nanobits of silica, or purified sand. Together they produce a "sheer-thickening liquid" that stiffens instantly into a shield when hit hard by an object. It reverts to its liquid state just as fast when the energy from the projectile dissipates.'"
But how much would it cost to coat your car in this stuff? And would it give extra protection?
Nope, not if it's your safety you're worried about, rather than the cars. You want the car to deform, so your decelleration slows down. Just like a helmet, you want it to break so you don't.
Trust the Computer. The Computer is your friend.
True story: I had a neighbour who just could not grasp this concept. They'd heard about a modern car which had crumpled really badly in a relatively minor accident, writing it off. They'd therefore decided that older cars built like brick outhouses were far "better", because you might still have a car after the accident.
Try as I might, complete with diagrams and models, I could not get across the idea that this was a good thing, and that had the car not done the crumpling, the passengers would have - and who cares if the car's repairable when everyone in it's dead?
You'll still get an impact from the energy alone. You're not thrown back, but certainly hit. I imagine that hundreds of bullets would be enough to cause some quite significant effects anyway. (The total heating alone could be "interesting".)
...but look down. We'd have joined each other in death.
--Dune
You'd need to have a high enough amplitude and frequency to cause the goop to shear against itself from the sound; I'm not quite sure, but gut feel says you wouldn't need to immobilize them since you'd be doing horrible things to their skin and organs already.
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Not really, polyetylene glycol (PEG) != ethylene glycol.
But anyway, both PEG, and sand are really cheap, so depending on what is published you should be able to make this at home if you are so inclined.
I'd also expect the DuPont company to try to bring this to market - maybe in their auto paints? I'd be willing to bet they provided significant funding based on the fact that the demo utilized kevlar, and that the research was done at the university of delaware.
I wonder how simple this really is, while PEGs vary greatly in molecular weight, and there is an infinite span of concentrations, really, knowing only what the video told us, anyone with an interest should be able to figure it out.
Yes, but (a) the rigid armor is "flexible" in terms of the joints between the plates, and (b) doesn't cover the whole body - whereas presumably this would be shirt, trousers, the lot. The parent's question was whether they could run in the liquid armor... IE the video states that the liquid solidifies when agitated - are the forces of running enough to trigger the solidification? What about with full battle kit slapping around on your back? Or when you slip in what's left of your buddy's intestines and land flat on your face? Or (as another poster put it) some other applied force may be sufficient to trigger it - sound waves, a blast of air, a sonic boom from a low-flying jet. If the stuff doesn't de-solidify in a hurry then the enemy could have a field day among the now "statuesque" soldiers...
Yep, and there are plenty of people that need an SUV for work or whatever. Most anti-SUV people I know don't have a problem with people that actually need something like that. The Chevy Suburban has existed since the 30s or something, LONG before the SUV moniker and hatred appeared, and they've sold models every year they made them.
Well because it's shear-thickening liquid, the more violent the impact, the more it locks up and spreads out the impact. One market that they are initially targeting is prison guards because the threat to them is from stabbing rather than gunshot or shrapnel, which the liquid armor stops yet remains flexable unlike plate armor that is rigid. The thing that will always annoy you when wearing armor is weight, heat build up and lack of flexability; this stuff should put a dent in all three.
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If this is really what you bought it for (and actually do), Congratulations. You are one of the 0.5 % of SUV owners who actually should own an SUV. Unfortunately, 99.5 % of them are owened by soccer moms and men who need to overcompensate for something, and are just endangering us all on the roads, and burning very excessive amounts of gasoline.
Your logic is indeed false. First, it is arriving with a velocity and an associated momentum, not a force. Force is imparted on the bullet to change it's momentum and direction. Thus if it's really bouncing in the opposite direction, then twice the energy is required to stop it is imparted to the armor. See the sarcastic reply under yours for why this is unlikely the case. Most fo the time it would likely be deflecting off, requiring less energy than that required to stop the bullet. However, this still tells you nothing of the force. The peak force imparted to the bullet will be determined by the interaction of the bullet with the armor and contact time of the bullet with the armor. However, it's not even the force that you care about, it's the pressure imparted to the tissue. This will be determined by how the force is distributed over the armor. The force will be much greater if it's distributed over a 1 cm^2 area as opposed to a 1 m^2 area. To sum up, it's complicated and you can't draw conclusions of the performance of this armor by whether it "bounces off" or not.