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U.S. body armor, good stuff.


Lee
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It did exactly what it was supposed to do. The flexible kevlar is actually designed exactly for that...stopping shrapnal...so I'm not really suprised all that much, except to say that must have hurt like hell....like getting a shot to the kidney with a bat. The SAPI plates are specifically for bullets....up to 7.62mm AP actually.

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Rustman, correct me if Im wrong, but dont the SAPI plates demand a inner layer of kevlar as well to be totally safe? think I heard somewhere that when SAPI plate gets hit there is risk of parts coming loss, and the inner kevlar is there to stop those parts from entering the body?

/Thomas

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Yes. SAPI's are "ICW", "In Conjunction With" underlying soft armour.

Correct. The whole thing is essentially soft kevlar. Obviously it's been improved...design is better and all...but it really isn't all that much different from the old flak vests. It's just that on the front and the back there are large pouches to hold the SAPI plates. Another improvement is because it's a MOLLE setup the armor is modular. In the case of the video, what actually took the hit was his side SAPI...it's like an addon soft armor and pouch for a smaller SAPI that attaches to the flanks under the arm pits...the base vest doesn't actually have protection there. It really is good stuff. Our sister company had a dude step on a pressure plate IED...He lost his leg, unfortunately, but he survived it with otherwise little permanent damage. His body armor was just shredded from crotch right up to the throat...it held up though and nothing got through to take out anything vital.

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My understanding is that this is similar to what the Stryker has for armor. The outside is hard and designed to deflect/defeat projectiles of various sorts. The inside is lined with layers of "soft" Kevlar to reduce the effects of the fragmentation of the outer armor and/or incoming mass. Or as they say in vehicle terms, "spalling".

Kevlar is an amazing thing, but it doesn't do squat against certain threats. For example, it is possible to take a sharp dagger and stab right through a Kevlar vest. You might not get all the way into the wearer's body, but with reasonable force you can do damage. A sharp dagger against SAPI doesn't do squat. Yet a piece of shrapnel can be arrested quite successfully by Kevlar, even though it is probably traveling with more force. The difference is that the force isn't directed towards a single point of impact with optimized cutting properties like a knife has.

At least this is how it's been explained to me by geeks who seem to understand this stuff :)

As an aside, I wear Kevlar chaps when I am working with a chainsaw. The purpose of the chaps is not to "defeat" the chainsaw's hardened steel teeth, since that's impossible. What it instead does is entangle itself on the teeth so that chain binds up and the saw stalls. Nylon apparently also works, though not as well because the fibers are not as resistant to being sliced clean through. The chaps will look like Hell when it's over, and the wearer might get a decent gash, but compared to what would have happened... not a big deal. Fortunately, I have not put this to the test!

Steve

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Flanker15,

So basically it's modernized chain mail.

An excellent analogy. Chain mail does offer similar protection to weapons of its day as soft Kevlar does to today's threats. Plate mail offers similar protection, relatively speaking, as SAPI does. The flexible properties of one allow it to be used to cover bits of the body which solid inflexible armor can't.

Steve

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In one of my previous incarnations I dealt with chainsaws, the nylon protective clothing is fine if its multi layered, then you just get bruised. Trouble is the full rig, jacket, chaps and gloves and helmet plus face guard is very hot, still one of our drivers saw a person amputate his leg so I always prefered to sweat, rather than learn how to cope, sans one of my limbs.

I knew about the kevlar versus sharp objects incompatability, so what are knife proof vests made of?

Talking of medieval armour the modern vests seem to be reinventions of the reinforced or brigandine surcoat. Given developments in 'super spider silk', nano-technologies and nano-composites when do we retire the humble bullet? Or will the infantry now be sucked into the armament/armour arguments that delight or frustrate, depending on your viewpoint.

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Rustman: That's what I mean, it worked really well, even though that was one big hunk of metal. :) Also, apparently from what the guys in the video are saying, he didn't even know about being hit when it happened, not until they noticed the hole days later, which is why they are taking it out now in the video. So it seems the vest so effectively stopped and dulled the impact from that shrapnel that he didn't even know he'd been hit, pretty impressive. :) These new vests work great, without being so heavy as to be useless for regular wear while on close patrol.

They said it didn't hit his side plate, so I agree, I think it hit the kevlar panel that you can place on the side. They have added an option for a side plate to this vest.

On the subject of armor in general; as is often the case on many topics, the more things change, the more they stay the same. :)

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Kevlar is an amazing thing, but it doesn't do squat against certain threats. For example, it is possible to take a sharp dagger and stab right through a Kevlar vest. You might not get all the way into the wearer's body, but with reasonable force you can do damage. A sharp dagger against SAPI doesn't do squat. Yet a piece of shrapnel can be arrested quite successfully by Kevlar, even though it is probably traveling with more force. The difference is that the force isn't directed towards a single point of impact with optimized cutting properties like a knife has.

Steve

Out of curiosity - how is a "stab" vest designed differently? Are there multi purpose vests intended to protect from both threats?

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Vark,

In one of my previous incarnations I dealt with chainsaws, the nylon protective clothing is fine if its multi layered, then you just get bruised. Trouble is the full rig, jacket, chaps and gloves and helmet plus face guard is very hot, still one of our drivers saw a person amputate his leg so I always prefered to sweat, rather than learn how to cope, sans one of my limbs.

Yeah, sweating is a side effect, but a much better one than a stump. However, I don't wear the jacket. I stop cutting if I'm too tired, so my chances of doing in something other than a thigh are quite small. Thighs are nice targets even when fresh!

I knew about the kevlar versus sharp objects incompatability, so what are knife proof vests made of?

No idea, so I Googled :) Here's a patent on a steel based one:

http://www.freepatentsonline.com/6842908.html

I saw vague descriptions of recently invented fabric based stuff, like this:

http://policevehicletech.com/vmax.html

The difference is probably in how things are layered. Kevlar is designed to provide high tinsel strength (i.e. not tear). Much the way fishing line is very strong when being pulled on, but can be cut by almost anything. This is why it is used in mountain climbing ropes, sails, hang gliders, boat hulls, and all kinds of things where materials are stressed laterally. When a shell fragment hits a vest this is kinda what happens too. The fragment tries to push its way in by breaking the strands. It does cut them too, but that's why the layers are quite thick. It appears to be a system where mass of fibers wins. Otherwise Kevlar vests would be one layer of strands, like Mithril :D

The strands and layering of the stab resistant fabric must be designed to resist severing instead of breaking. Oh, like the difference between steel wire and fishing line. It's possible that fishing line of a particular strength is just as good, if not better, at resisting breakage compared to a particular steel wire, but the steel wire requires more specialized cutting devices than are needed to cut the fishing line. You know, a pocket knife can cut the fishing line while heavy scissors or shears are needed to cut the wire.

Or something like that :D

Talking of medieval armour the modern vests seem to be reinventions of the reinforced or brigandine surcoat. Given developments in 'super spider silk', nano-technologies and nano-composites when do we retire the humble bullet? Or will the infantry now be sucked into the armament/armour arguments that delight or frustrate, depending on your viewpoint.

Definitely a new arms race. No nation likes the thought of being unable to kill its enemies in large numbers if need be!

Steve

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Out of curiosity - how is a "stab" vest designed differently? Are there multi purpose vests intended to protect from both threats?

Anti-stab plates have different materials that resist stabbing... for example, titanium inserts are popular for EMTs (little 5x8" chest pieces to cover the truly vital circulatory areas), and something called "STABOND" is in use.

Most vests provide fewer square inches of anti-stab than ballistic protection (because they use inserts). I believe some are now available with matching coverage.

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Interesting, I think that we will soon come to a point which is the similar of the 1970's "the tank is dead" hype, after the Yom Kippur war. Given the technological dvelopments are overwhelmingly on body armour and given the only real difference in modern rifles, compared to the models 20-30 years back is in add ons, optics, laser/target pointers when does the equation become so unbalanced that the basic infantry rifle becomes a secondary weapon, compared to a high tech lucerne hammer or halberd?

I'm not saying that the modern firearm has no room for organic development, propulsion, sub-calibre rounds etc but every few months it seems new developments are occuring in defensive technologies that are not matched by offensive ones. To put it another way, in science fiction terms (real sci-fi not space opera) we are far closer to some of their descriptions of body armour than we are to their ideas of weapons. Or is it just the case that body armour has so lagged behind projectile technology that all we are witnessing is a rapid catch up made possible by previously inaccessible technologies, technologies which favour the protection side of the equation. After this surge, parity is achieved followed by a typical leapfrog, threat, counter-threat dynamic.

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It is worth noting that, for the most part, current conflicts involve people with both money and body armor fighting people with neither. This has greatly reduced the motivation of the western defense contractors to produce and market a really good body armor defeat solution. They couldn't get paid, and if they tried they would be charged with treason anyway.

The current insurgent solution is to base their entire approach around IEDs, suicide attacks, and leave and forget indirect fire of various sorts. If the boffins ever produce a decent explosives detector the "red" side is going to have to do some serious thinking, and quickly.

The technologies are falling into place fairly rapidly for something close to Heinlein's "Mobile Infantry" powered armor. Of course as soon as the powered part starts to become available all bets are off because you can carry a MUCH bigger bang stick. There was an article just this week about some bright fellow finally cracking a big piece of the puzzle on producing carbon nanotubes in truly useful lengths and quantities.

http://www.gizmag.com/nanokites-nanotechnology-swnt/12434/

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Dan, good point, the exception would be the Israelis who fought Hizbollah troops http://counterterrorismblog.org/2006/07/worst_case_scenario_hezbollahs.php. In that case their small arms development has been to add sensors to weapons and develop remote systems, as witnessed in the Gaza offensive.

Another good website, with excellent links, if you have the time is

http://www.defensereview.com/future-body-armor-is-nanotech-ballistic-fiber-the-next-step/

I agree with the Henlein allusion but think it more likely that we will be looking at "The Forever War" concepts more that "Starship Troopers", especially the use of obsolete weapons, though the stasis field is a bit beyond our tech level! The unclassified data on powered armour suggests heavier load bearing capabilities but unless the weapon is recoilless you still have to contend with Newton's third law of motion. Battletech anyone?

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"Battletech anyone?" : Unfortunately, as soon as you get bigger than a form fitting suit for a single soldier surface to mass to volume ratios mean wind up with something that looks a lot like an Abrams. It is the basic shape that allows a given amount of armor to provide the maximum amount of protection.

Actually all of those ratios apply to said soldier as well. But the com links are not there yet for truly unmanned ground forces.

I really do think that some form of powered armored suit is coming fairly quickly for things like high intensity MOUT operations. The HEAVY in heavy infantry is going to apply to more than their supporting equipment for the first time in several centuries.

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