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Polyethylene Bulletproof Vests Better Than Kevlar
teflonscout writes "When I think of bulletproof vests, the first word that comes to mind is Kevlar. Wired is running a story on Dynema SB61, a bulletproof material that is made of polyethylene. It is a higher grade of the plastic found in Tupperware. The story also mentions the recall of Second Chance bulletproof vests that were made from Zylon, a material that degraded slowly when exposed to moisture. At least one police officer was injured when a bullet penetrated his Zylon vest. Polyethylene is impervious to moisture. The first vests made from this new material are 5mm thick and can stop a 9mm bullet traveling at 1777 feet per second, which is slightly better than other top of the line vests."
Dynema SB61, a bulletproof material that is made of polyethylene. It is a higher grade of the plastic found in Tupperware.
There goes my idea for a zip-tie & Tupperware bulletproof vest. It also explains why the prototypes failed in the field.
Trolling is a art,
Can't wait to see The Box O' Truth give it a try.
After what I put my tupperware through im not surprised that it can stop a bullet
Or you could just get some Dragon Skin armor that will take the force of an exploding hand grenade and not allow penetration...
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http://www.pinnaclearmor.com/body-armor/dragon-sk
Do they burp when they're hit?
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Mr. McGuire: Plastics
"doubt this technology will see iraq, oh and don't flame the truth, thanks"
Yes, don't flame the truth. Rather, flame the complete ignorance of the process by which new technologies trickle down to soldiers from the numerous trials and tests.
If it's good enough, it will eventually be used. The question then will be whether troops will still be in Iraq at that time.
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I think maybe they should rethink the name of the material ("Dynema SB61")when/if it goes into production.
I, for one, would rather not have my bulletproof vest sound like it's a cross of high explosives and bowel cleansing kits.
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"especially in hot/wet conditions"
And it really brings a whole new dimension to crotchpot cooking.
Like the stuff that's good enough that we already have, that to my knowledge, still isn't being used in Iraq?
Maybe it's a few months out of date, but last I heard, the only troops who have bullet resistant body armor over there are the ones who's families bought/shipped it, or got it from an NPO that is buying them and shipping them to the troops.
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If you haven't heard about the history of "second chance" one of the very first commercial vest manufacturers, that is basically how they sold it. Walk into a police station, pull a gun, shoot oneself at point blank. Put the gun, vest, and business card on the front desk and walk out. As I understand they arrested the founder (Richard Davis) for firing a pistol within city limits, and placed a huge order. He eventually had to quit doing it because all the bruises from the gunshots were starting to give him heart problems.
Rather, flame the complete ignorance of the process by which new technologies trickle down to soldiers from the numerous trials and tests...If it's good enough, it will eventually be used.
Not quite. There's a lot of good products that should be used, but they aren't because of the almighty dollar. Usually it takes a few dead bodies, the tears of weeping mothers, pointed fingers, and fistfuls of public rage to force the government to supply adequate equipment to its troops. And even then they only supply it because of public image.
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Most current suits of body armor can stop a pistol caliber bullet. Rounds designed to pierce armor, or designed to be fired from a more powerful gun, are another story. Armor that will stop a small, soft bullet will still be penetrated by a faster, or less malleable one.
For civilian or police protection, we have nearly impenetrable suits now; increasing their coverage, or decreasing their weight would be more practical (both of which can be achieved by making them out of lighter materials). For something like military protection, well, we may never have impenetrable body armor. Whenever defensive technology gets good enough, the military turns their attention to piercing those defenses; see for example the death of the battleship as a viable class of warship.
Apart from that, conservation of momentum applies. There is an upper limit whereby body armor would remain intact, while the flesh beneath is reduced to a pulp. Though admittedly conservation of momentum also applies to the shooter, and to the recoil of their gun, so there is a similar upper limit for muzzle velocity per unit of projectile mass.
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1) You are equating weight with stopping power for different materials. That is an incorrect comparison. That might make sense when comparing two vests of the same material and design. Vest A has 10 lbs of Kevlar, Vest B has 20 lbs Kevlar. Both vests are of similar designs and Vest B should be better at stopping bullets. However if another company designed a different type vest (Vest C) with Kevlar that had better stopping power but only used 10 lbs Kevlar, the use of weight alone in comparing effectiveness would not be valid.
2) Body armor is heavy, especially considering all the other gear a soldier has to carry. If body armor was lighter and provided the same amount of protection, many soldiers would prefer it.
Well, there's spam egg sausage and spam, that's not got much spam in it.
If it's basically like wearing a big plastic slab, isn't that going to get super hot?
That's why you lacquer the chestplates in white to dissipate heat, and give them a black spandex bodysuit underneath...add a scary looking helmet and most of your vitals are covered. In theory it should deflect blaster bolts. Where I'm stationed we wear them all the time (I work in law enforcement).
In practice, they don't stop crap. Like last week this scruffy-looking nutjob with a walking carpet for a sidekick breaks in to rescue his girlfriend. Next thing we know there's a weapons malfunction down in the cell block, and four of my buddies find out the chestplates don't quite work as advertised.
I hate this posting...maybe I can get transferred before something else goes wrong.
- TK421
Study everything, you'll find something you can use - Jason Bourne
Best part is that most "saves" the vests are credited with are from car accidents, where the vest acted as extra support, etc. for the spine and whatnot....
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Perhaps it can be combined with the liquid body armor for extra protection.
Soft body armor is designed to defeat handgun bullets, which is why it is so useful for police. Hard body armor is much bulkier but is designed to defeat rifle rounds. In general, a rifle round is significantly more powerful than handgun rounds.
Because if you carry less weight in body armor, you carry more weight in ammunition, med supplies, whatever. The protection they have today is generally sufficient for small arms rounds, so they don't usually need more protection. Reducing the weight of current equipment, however, goes a long way toward making your troops more mobile, responsive, and better prepared to face an enemy. Not to mention, it makes them feel better to not lift a 35 pound vest over their head.
I've worn the modern vests, and while they aren't nearly as bad as they were 10 years ago, they still aren't good. If I could get the same protection from something even a quarter less weight, I'd make the switch without a second thought. That two or three extra pounds can mean the difference of being able to march my ass another couple of kilometers to safety or have a few extra rounds of ammunition when I really need it. That's a huge mental advantage, and despite all we say about war, it's the mental aspects (on the soldier) that make it difficult in the long run.
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This is one of those cases where allegory is truly misleading. The article makes the comparison to shopping bags and tupperware in order to emphasize the "everyday" nature of the material. The truth is that they have similar basic components, but the exact composition and processing differences cause one material to be good at resisting bullets and another at storing food (or selling at parties.) Unlike Tupperware, Dyneema vests are composed of woven and laminated fabric.
Dyneema is actually a trade name for a thread derived from Ultra High Molecular Weight polyethylene. The intrinsic strength of the material comes from the ability to increase the length of the polyethylene chain to extreme lengths. Since the structure of UHMW derives its strength mostly from the intermolecular Van-der Waals forces, the longer the polythethylene chains get, the stronger the forces holding the material together become. When the processing of the polythylene allows the length of the chains to become uniform, then you can engineer it into useful forms, such as a fiber which eventually be formed into fabric, then laminated and put on your chest.
Of course, being UHMW, Dyneema has a weakness: Its melting point is about 300 degrees Fahrenheit, or about the temperature of a hot light bulb. Which means that while your body heat might not harm the vest, carelessness in storage might.
Independent tests do not support the army's conclusions. Since there is already some question about the validity of the army's tests (e.g. the designer of the vest that "won" in the army's test says that dragon skin is actually better, the person who conducted the army tests left to work for a dragon skin competitor, etc.) I don't think just repeating the army's conclusions (or quoting the Washington Compost as doing so) really proves anything.
--MarkusQ
I hear Endor's a pretty easy assignment.
As with anything, the devil's in the details. From a previous trip around the web in re: bodyarmor.
It's not Tupperware, but 'Ultra high molecular weight polyethylene'.
See also:
Spectra
Dyneema
Aramids (from "aromatic polyamide")
- Example: Twaron
Kevlar, of course.
Also Nomex - known for it's heat-resistant attributes, also strong. It's an "aromatic nylon, the meta variant of the para-aramid Kevlar."
Of course, it is great marketing to show that your body armor can stop all rounds up to a 30mm A-10 round, but what LEOs really need is something a bit less.
If I could invent two types of armor, one that worked against a 30mm round, but looked like the bomb disposal suit, and a piece of armor that only worked against 22 caliber rimfire, but looked and felt identical to a cotton T-shirt; the Tshirt-like armor would be the real success.
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The low melting point is also not good in combat situations.
Its highly recommended to wear *cotton* and not nylon clothes, for example, because cotton won't melt to your skin if you survive an IED attack.
-- My Sig is a P228.
My Ph.D. project happens to be on super-fibre materials, nice coincidence.
As it happens, dyneema is highly stretched polyethylene. As such, it melts at a fairly low temperature (and performs less well before reaching such temeratures. Temperatures around 80 degrees centigrade would do...). Twaron and Kevlar are aramids. They decompose at around 400 degrees, and hardly any change in performance is seen.
Now, 80 degrees C is a quite high temperature, but with a (desert) sun baking on a vest, I would rather wear the slightly heavier aramid vest.
B.
Every experiment which ends in a big bang is a good experiment.
Strictly speaking, rifles are small arms. Generally, "small arms" is a term that encompasses anything a soldier can fire unsupported.
Reality has a conservative bias: it conserves mass, energy, momentum...
There's another factor here too that many people don't consider. Even if the vest *were* to completely stop the penetration of a high powered rifle round, there would still be severe injuries to the person. All the kinetic energy from the bullet has to go somewhere...the vest may stop penetration but all that energy can't just mysteriously disappear. That's why when someone gets hit with a high powered round, even if the vest completely stops the bullet, they often get burns, bruises, and sometimes broken bones. There's no way around this until someone invents inertial dampeners.
I'm from the small town in Michigan in which second chance was founded, and I know the entire history of the "incident"
The officer in that shooting was shot 6 or 7 times. *ONE* bullet penetrated the Zylon, and it was on the periphery of the vest. The edges of *ANY* vest are vulnerable and not as strong as center-mass.
Second chance has 960+ confirmed saves with their body armor.
What they've done to the second chance business as a result is, on the whole, a travesty. They were/are one of the few american manufacturers, and they did nothing wrong at all.
I've been using polyethylene armor on my fighting robots for years. It's extremely tough, lightweight, and relatively cheap. There was a fashion for using polycarbonate (Lexan) on fighting robots for a while, and while it looks cool (it's clear), it just can't take impact like UHMW polyethylene.
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Which is how my tired morning eyes read that headline.
The idea that FMJ bullets tend to zip straight through people leaving a relatively simple wound developed in the late 19th century when ammunition was commonly loaded with flat-based, round-nosed bullets. These bullets were inherently pretty stable due to their center of gravity being forward of the middle of the bullet.
When the spitzer (pointed) bullet was developed in an effort to improve the bullet's aerodynamics and increase range, a secondary effect was discovered. The longer point of the spitzer bullets caused the center of gravity to be pushed more toward the rear of the bullet. This resulted in bullets that were inherently inclined to travel backwards. The gun's rifling was adequate to stabilize these bullets in a point forward orientation through the air, but when they encountered a denser medium (such as a human body) the bullets would tumble as it tried to reorient it's self. The tumbling bullet caused much more sever wounding than the 'icepick' type wounds seen with the older round-nose bullets. Often the combination of tumbling and centrifugal forces (bullets commonly spin in excess of 100,000 rpm) causes the bullet to break into fragments and cause even more nasty wounds (often far worse than what would be seen with soft-point or hollow-point expanding bullets).
Bullet fragmentation is a critical factor in the wounding characteristics of modern military rifle bullets.
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