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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.'"
There's a video on break.com where you can see the liquid armor in action - it's pretty amazing:
clicky
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Although I am not sure what the point of it being in this state protects more? Does it weigh less?
:D
Anyway kids if you want to create your own non-newtonian fluid fluid at home heres how.
1. Get your custard power, or corn starch (think baking soda can be used too).
2. Get a dish or a cup. More fun with a large jar though.
3. Add some water to the container and proceed to mix as much powder as possible into the water until it gets to a weird creamy/solid state.
You now have something which is a liquid and solid at the same time. Enjoy!
If the clothing is loose enough the knife/point object would still penetrate the skin, it just would be taking the fabric along for the ride.
I read awhile back (old wives tale maybe?) that being stabbed while wearing kevlar isn't always going to protect you as the knife does not have to penetrate the kevlar to penetrate the skin, especially cavity areas.
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This stuff sounds like a dilatant.
Kitchen experiment: take some cornflour and some water. Mix one part of water to about two parts of cornflour until you get a thick paste. Play with it.
If you apply gentle pressure, it behaves like a fluid. If you apply strong pressure, it abruptly solidifies. Scoop up a handful and throw it at something, and it'll bounce. Drop something heavy into a bucket of it and it'll sink.
Beach sand also manifests this behaviour, under certain situations; occasionally you can find a patch of heavily waterlogged sand that's rock hard when you walk across it, but if you stand still you slowly find yourself sinking in.
Disclaimer: cornflour almost certainly does not make good body armour.
Armor-piercing bullets tend to create less damaging wounds than soft bullets that are designed to expand upon impact and dump all of their energy quickly.
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Sounds a bit like corn starch. From my PMK days (sigh, Alisha), I remember seeing demos of cornstarch mixed with water. It appears liquidy, but if you smack your hand down in it, it turns to a solid instantly and temporarily, so no splashing occurs. Kinda freaky.
The WikiPedia entry actually has a video of this.
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If you think that then Herbert caught you as he did me and so many others. You need to read the first three of the series as a single piece of work whose overarching theme is: superheroes - whether good or evil - are dangerous to humanity. It's easy to stop at the end of Dune and rejoice in the final triumph of Paul and the defeat of the bad guys, and then miss his decline and eventual humiliation in the next two books, because the events he triggered have gone beyond his control.
Tim O'Reilly's biography of Herbert explains the author's purpose very well. It's available online here.
--- Hot Shot City is particularly good.
Well, it's not the entire suit that stiffens, just the area local to the impact. This armor coating is intended to protect you from being penetrated by a bullet but chances are even if you're wearing this, if you get hit (in the chest for instance) you're going to have the wind knocked out of you and be vulnerable to more attacks anyway. That's why the military doesn't send people out to fight alone, they have others with them to protect them until they can re-arm themselves.
The eggs one won't work, because the eggshell is rigid, and so provides no shear force on the coating. The trampoline one should work, but the effect you'd feel is negligible - this stuff works well at the speed of bullets, but at that small thickness you'd get little effect at the speed of a person's bounce. If you could get bubbles to work, then they'd still pop - they'd just pop slowly, since as the sides pull away from the initial point of zero thickness they'd cap their own speed.
Yeah, I did projects on this stuff. You can make some yourself with 1 part water and 1.44 parts cornflour; put it in at 1:1.3, then continue to add the rest of the flour while pouring. It'll get difficult to mix (don't do it in a machine, you'll break the machine, it's like stirring rocks at that speed) but a minute of perseverance will give you something you can bounce your thumb off or sink your finger in. Good fun. Kids love it, and it's easy to clean off; if it gets onto clothes then it just rinses out.
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Your example relies on a signficant difference in mass as well as overall rigidity of the two vehicles in question. Deformable frames being about absorbing energy (and momentum, being an inelastic collision) in an impact. An M1 brings way more Kinetic Energy to the impact than can be absorbed by a deforming frame of a Toyota.
The safety of the passengers is dependent on how quickly the vehicle passenger compartment decelerates, as that will determine with what force they impact the interior of the vehicle (the so-called "second impact"). The M1 will not decelerate very much, but it is because of the mass disparity, not that it is rigid.
Obviously a crumple zone cannot absorb an unlimited amount of energy, but up to the amount it can absorb it is definitely good for you, whether you are hitting something rigid or not.
Actually, this is not true. I've got some friends who do car safety analysis all the time and they say that a modern crumple zone + rigid passenger egg is safer than a rigid car or light truck in a collision - the crumple zone absorbs most of its car's energy and the rigid car flips over.
There are many dead SUV drivers to disprove your claim.
Except 3 rounds from a 45. planted square on his chest will either A: Knock him on his ass. B: Bruise his chest and wind him C: If your lucky pop his sternum D: All of the above Body armor just makes it so the round doesn't kill you. It still hurts like hell. Your body is still absorbing the energy of the round.
You mad
Not necessarily. The liquid armor in question is a dilatant. It should provide stiffening in any region in which there is a large shear stress (there is definately a large shear component in a "crushing" auto accident.) While I doubt that this technology could protect you from a truck impact, it would likely stiffen the region of impact. This could be a good thing, like if you are being T-boned - the added rigidity increases the amount of impact your vehicle's side could withstand, or it could be a bad thing, reducing the effectiveness of the crumple zones in a head on collision.
Wish I could remember the mag I read it in, but there is some company working Motocross gear made from simialr stuff. It created a Roost Guard (chest/shoulder protector) from foam coated with this stuff. The foam was flexible until impact, then the foam became rigid absorbing the impact. The rigidity was based on the speed of compression of the foam. The faster the impact the harder the foam. So for regular riding, it was like wearing a 1/2" layer of flexible foam. If the bike in front spit up a rock, it hit your chest and became hard during the impact then soft again. Or as soon as you went over your bars and landed on your shoulder, the shoulder area became rigid during impact then soft as you lay on the ground wondering what happpend. The last demo was actually going into the bars with your chest and having the whole chest plate harden during impact!
I think the projected public delivery date was around 2008 but for the life of me I cant find the article again. I do remember that it was a British company making the stuff.
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No.
Modern body armor fails against anything sufficiently pointy or fast. Knifes and daggers will go right through Kevlar, as will small, fast bullets typically found in rifles (e.g. 5.56 NATO or 22 Magnum Rimfire).
Second Chance and Point Blank used to have more information on their websites, but maybe that was before the WTC destruction. Here's a page that at least hints at different products for protection from ballistic and hand weapons. Rigid, insertable "stab-" or "rifle-plates", sometimes made out of titanium or high-tech ceramic, offer more protection agains the fast and pointy attacks.
I've actually played with some of this stuff (I know the people who developed this, and by the way, there's no hyphen in Delaware, despite what BusinessWeek thinks) and yes, I don't see why they couldn't make butchers' gloves out of it. One of the easy demos they do is give you an ice pick and two pieces of kevlar and ask you to puncture each sheet. You can stab the ice pick through the normal kevlar but not through the shear-thickening fluid treated one. That should provide some protection against sudden knife slips that butchers might experience.
Even big heavy modern cars have crumple zones engineered in. A 6000 lb car with a crumple zone will always be safer than a 6000 lb car without a crumple zone.
Build a man a fire, he's warm for one night. Set him on fire, and he's warm for the rest of his life.
I became suspicious when I read the phrase "nano bits of silica". Nano technology my big toe: that's a marketing flourish.
The article mentions that this is a sheer thickening fluid, what they probably mean is shear thickening. That would be a fluid where the coefficient of viscosity increases with increasing strain rates, instead of remaining the classically Newtonian constant. In this case it's probably because the glycol tangles around the silica particles and can't untangle quickly.
While it's quite possible the material can become a semi-solid for the brief duration of a dynamic impact there is no reason to believe, and lots of reasons to not to believe, it becomes a particularly strong solid. In a particulate reinforced composite, which this is in its pseudo-solid state, the matrix (the ethylene glycol) is important to the strength and being a simple organic molecule it's strength must be on the same order of, say, polyethylene.
TFA itself infers this, noting the original idea of using the material itself (in peanut-butter mode) didn't work out. Instead it is employed as the matix in a conventional fiber composite using Kevar or Spectra or something like that as the workhorse.
As in all conventional fiber composites, the fiber bears the load, the matrix supports the fiber. In this case the support, I conjecture, amounts to preventing the fibers from displacing away from the impact point, probably allowing fewer layers of fiber to absorb a given impact energy.
Whle this is innovative and a good idea, it's hardly liquid armour. What I would hope for and maybe expect is better performance against pointy, hard, teflon-coated projectiles of the cop-killer variety which work by nosing the fibers out of the way.
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Larry Niven's Known Space series has armor exactly like this, that stiffens on impact. The only thing the armor has in common with Dune is that a slow impact gets through, IIRC in Dune they used some kind of force field. Larry describes what it's like to try to run in a suit like this while being peppered with automatic gunfire. Kinda funny. I don't think the Dune force fields stiffened up and made you fall over while being shot...
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Actually, it is not quite that simple. Remember, muzzle energy is mv^2, and while a 45 apc has a higher mass, it has a lower velocity than a 9mm luger. In general, there is not a large difference between the muzzle energy of a 45 apc and 9 mm luger, and some 9mm luger cartridges have a higher muzzle energy than some 45 apc cartridges (they are both available in a bewildering variety of loads).
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"Armor Piercing" is really a misnomer in a lot of cases. Most of the time, what people (civilians) are referring to are what have in times past been called "cop-killer" bullets (a name that was applied also to Teflon-coated [lubed] bullets) by the sensationalist media and what are more officially known as jacketed hollow-point (JHP) ammunition [a quick note: this is the most common form of self-defense ammunition carried by civilians in the USA and is totally legal to purchase and own]. These are designed to penetrate body armor and clothing better than standard unjacketed hollow-point (HP) rounds while maintaining the hollow-point's rapid expansion characteristics. A standard fully metal jacketed (FMJ) round gets better (tissue) penetration than a JHP, especially if the bullet is of "spitzer" style (pointed) as opposed to wadcutter or semi-wadcutter (flat-tipped) style. Due to complex mechanisms of expansion and point-of-impact material deformation, a lot of the time a JHP in a pistol will get better penetration through armor than an FMJ, but that is a topic for another day.
.223 Remington/5.56x45 NATO (the main cartridge of the M-16 and AK-101/108), 5.7x28mm (FN P90 round), 5.45x39 (AK-74), and 4.67HK (HK MP7). Additionally, some larger calibers simply have enough velocity and ballistic coefficient to pierce virtually all armor at very long ranges: 6.5mm Grendel (a few AR-15s), .30-06 (M1 Garand), and .50 BMG (M85 Barrett, M60) are a few such cartridges.
.45ACP round will result in a primary wound channel of .45". Shooting them with a JHP .45ACP will result in a wound channel (with a good bullet, like Speer Gold-Dot) of .7-.8". Bigger hole==bigger wound.
In the military sense, an "armor-piercing" projectile is a steel-(or tungsten-, or depleted uranium-)cored, brass- or copper-jacketed projectile that, upon impact will strike like a normal bullet or whatever caliber and then allow the penetrator to slip free of the bullet body and, by virtue of a very small cross-sectional area, penetrate deeply into the armor of the target.
Other bullets which are sometimes called "armor piercing" are standard rifle rounds (FMJ, BT, BTHP, OTM) in small-diameter calibers that easily puncture through most modern body armors. These are calibers such as
Oh, and the primary wounding mechanism for expanding rounds is not rapid energy dump but large wound channels provided by an expansion to up to twice the bullet's initial diameter. Shooting someone with an FMJ
I saw a fairly reputable television demonstration (http://fifthgear.five.tv/jsp/5gmain.jsp?lnk=601&f eatureid=301&pageid=-1) of a "rigid" vs "rigid passenger + crumple" offset head on impact. The two cars were a Land Rover Discovery and a Renault Espace MPV. The results were pretty spectacular and the Espace wins clearly. I also recommend the earlier test of "Old Espace" vs "New Espace" if you can track it down on the same site. (Found the video at Renaults web site http://www.renaulttv.co.uk/main.php?loadedSection= safety&loadedItem=safety_1&scrollPosY=8&uniq=)
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Point #1: Momentum is a vector quantity. This means that a bullet approaching a person from the left and a bullet leaving said person, heading right, have totally different momentum vectors.
Point #2: In situations where outside forces can be ignored (such as a bullet impact), momentum is said to be "conserved". This means that any momentum change the bullet experiences has to be equal and opposite to the momentum change the person experiences. A bullet of mass "m" which is travelling to the right at speed "v" has momentum "mv" (taking the direction "right" to be positive). Similarly, the same bullet travelling to the left at speed "v" has momentum "-mv". Therefore, a bullet which ricochets off at its initial speed has TWICE the momentum change compared to a bullet which simply stops. As a result, the person has to experience double the momentum change as well.
This means that a ricochet imparts MORE momentum to the target than an embedded bullet would, which is (as another poster remarked) why solar sails are reflective.
How the hell did this get modded to +5? This deserves a "-1, poster probably failed Introduction to Physics" mod option.
It is always safer to be in a deforming vehicle during a crash, assuming the vehicle doesn't deform so much that it crushes you. It doesn't matter whether you're crashing into a tree, an SUV, a tank, or another deforming vehicle.
If you hit a crumpling vehicle with your truck, the crumpling will decrease the elasticity of the collision and reduce the acceleration experienced by both drivers by some amount - but if you had also been in a crumpling vehicle it would have increased the inelasticity of the collision even more and doubled the safety factor introduced by the crumple zones.
In your ridiculous example of a tank hitting a Toyota, the tank crew will be safe because the tank's much, much larger mass would result in much less acceleration on the part of the tank. The rigidity of the tank's frame wouldn't have anything to do with it. In fact, it the tank were to crumple during its impact with the Toyota then the tank crew would actually experience even less acceleration during the collision.
Instead of cars, think about it like this: You are about to crash into an object at a high speed. Would you rather have a rigid object between you and the impacting surface, or a soft object?