Bomb-Proof Wallpaper Developed 388
MikeChino writes "Working in partnership with the US Army Corp of Engineers, Berry Plastics has rolled out a new breed of bomb-proof wallpaper. Dubbed the X-Flex Blast Protection System, the wallpaper is so effective that a single layer can keep a wrecking ball from smashing through a brick wall, and a double layer can stop blunt objects (i.e. a flying 2×4) from knocking down drywall. According to its designers, covering an entire room takes less than an hour."
Discovery channel beat them to it. (Score:5, Informative)
Rhino liner works great [rhinolinin...strial.com]
Re:Wallpaper anchored in demo (Score:5, Informative)
Re:Forget bombs, think hurricanes and tornados! (Score:4, Informative)
Really, it's useless for hurricanes, aside from in places where people wouldn't be prepared for a hurricane anyway.
At the very least, Florida's building code is such that, for anything built in the last 17 years (at least - I know the standards were strengthened after Andrew), the wind causing impacts is not what does damage - Aside from to windows. It's the the wind speed and pressure differences that destroy roofs and cause structural damage, and flooding that causes the most damage, really.
Whoo, being a Floridian does have it's uses.
Re:Kevlar (Score:4, Informative)
Re:Felt (Score:2, Informative)
No I agree. Longbows made armoured knights obsolete.
The Battle of Agincourt showed how effective longbows were vs plate.
But in hand-to-hand combat, plate's weakness was a concussion weapon.
And my original point in posting was that felt plus chain was sufficient to protect against most arrows.
Sorry I came in in the middle of the argument.
and every foot-soldier wore a vest of thick felt and a coat of mail so dense and strong that our arrows made no impression on them. They shot at us with their great arbalists, wounding the Moslem horses and their riders. I saw some with from one to ten arrows sticking in them, and still advancing at their ordinary pace without leaving the ranks.
Re:Felt (Score:3, Informative)
That's one of those "Yes, but..." things. It has to be taken in context. Yes, plate armor was vulnerable to "denting" weapons. If your armor was crushed around you, you could be disabled even if you were not particularly injured.
But that has to be compared to the protection that mail armor offered against crushing weapons... which was virtually none. Your armor would not be crushed around you, you would just be crushed instead. So plate armor was still far superior in that sense.
Re:Forget bombs, think hurricanes and tornados! (Score:4, Informative)
This seems to be a common misconception, probably due to it being taught badly in schools. Taking an aeroplane as a specific example since this is the most common example of lift. You will find that the Bernoulli effect (the lift generated by a pressure difference above and below the wing) is not the main reason why planes fly (although the effect does exist, it is just not a large enough force to keep a plane up).
What demonstrate this most clearly are symmetrical winged aeroplanes which are things like stunt planes which often fly upside down. It should be evident from the fact the wing is symmetrical that the common explanation of lower pressure above because air goes around a curve making it go faster has zero effect here.
If you have paid attention carefully when flying you may have noticed that a plane does not fly completely flat most of the time. There is a small angle between the planes wings and the direction of travel. Because air tends to follow the surface of the wing (sometimes called the Coanda effect) this means that the air gets deflected downwards by the wing. If the air accelerates down then by Newton's laws there is an equal and opposite force upwards on the plane generating lift so it can then fly.
I have not read anything about how houses are affected but I would imagine it would be a similar effect with the roof deflecting air causing a force.
Re:Felt (Score:3, Informative)
Also: The best way to defeat a well armored foe was not an impact weapon - felt and padding under the maille and plate stopped most of the damage - but stuff like http://www.crazywolffarms.com/images/pollaxe_1_.jpg [crazywolffarms.com] that bad boy. Polearms and short weapons. If you get a knight off his horse and stun him long enough to shove a dagger through his eyes, he's fucked.
Re:Kevlar (Score:4, Informative)
While I am not "calling bullshit", as it were, I find the story of the silk armor to be a bit incredible. I am pretty familiar with silk and its properties. I am not saying it was not popular, or that there were not stories, but I seriously question the effectiveness of any quantity of silk that anyone but a "noble born" could afford, as armor.
What I can say with authority, however, is that kevlar, by itself, is not and has never been particularly effective against "firearms" in general. It can prevent the penetration of certain handgun rounds, but by no means all, and still allows considerable damage to the wearer. For the most part kevlar vests were worn by law enforcement and the military to reduce damage, not prevent it. Even for the handgun calibers that kevlar would normally stop, pointy jacketed and/or hardened slugs can still penetrate kevlar like butter. Even relatively low-power rifles will punch straight through a kevlar vest.
However, the combination of kevlar and high-tech ceramics ("Dragon Skin" is probably the best example) can withstand a hit from a relatively high-powered rifle, and with relatively little damage to the wearer. Especially if some of the newer aramid-type fibers are used instead of kevlar. But those developments are VERY recent... no more than a few years.
Re:Kevlar (Score:5, Informative)
Um, you might want to check your history again. The longbow was the weapon that made plate body armor obsolete.
Actually it wasn't. Plate armor was widely used in Europe after the Battle of Agincourt in 1415; arguably it gained in popularity.
It was very difficult to pierce plate with a longbow. The English victory at Agincourt is more due to the terrain than anything else; arguably plalte became even more popular after Agincourt, precisely because it offered reasonable protection against arrows. (Protecting horses etc. was another matter.) The crossbow did a much better job against plate armor. It delivered more kinetic energy, and it took much less time to train a crossbowman than a longbowman. Firearms did the rest in the 15th and 16 century. The single most driving factor, however, was cost - plate armor was too expensive to make and maintain, and if you can hire a whole squad of Landsknechts (arquebusiers, what have you) for the same money it takes to have plate armor made for yourself, the arquebusiers win. At that point, however, longbows had already been obsolete for more than a century.
Re:Kevlar (Score:4, Informative)
This, also, is misleading. Some of the most spectacular remaining samples and artwork of armor are plate, but are for _jousting_. Like modern bomb-proof armor, what is worn for such a specialized use is far bulkier, more expensive, and heavier than actual combat armor. And even the best plate was often supplemented at joints such as knees and elbows and hands, with chain where making joints out of plate would be too awkward or expensive.
Also, the better plate of the Middle ages was certainly capable of stopping the ordinary "clothyard shaft" of the longbow. The tips of the clothyard shaft were typically rather soft, inexpensive steel: it _flattens_, bends, and glances off with even a quite direct hit on a good quality breast plate or helmet. (Yes, I've seen this tried.)
It is misleading to say "the bow and arrow drove the change" when the bow and arrow predate civilizaiton: plate armor does not. Other factors include the introduction of the _inexpensive_ long bow: the price of a single armored knight was easily undercut by the price of 20 farm boys with bows, and they could produce an arrow storm that would not only kill the knight's less armored steed, but was likely to put clothyard shafts in his joints. Couple that with a muddy field where a knight's boots and heavy armor will bog down, such as occurred at Agincourt, and the yeomen with daggers could easily beat the French knights to death, force their visors into the mud to drown, and shove daggers into their eye slits.
The concept of "plate" long predates the middle ages, remember: even the Greeks and wealthiest Egyptins had breast plates or bronze, quite effective against the weapons of their time. Their efforts were limited by weight and the strength of the metal, but it was certainly the ancestor of "plate".
Re:Forget bombs, think hurricanes and tornados! (Score:3, Informative)
The reason for symmetrical wings on aerobatic aircraft is that they impede the flow even more and allow much greater control, at the expense of fuel efficiency.
You would think that wikipedia would agree with your assessment if you were correct, but no, no they don't. Have a read. [wikipedia.org]
Re:Felt (Score:5, Informative)
Re:Wallpaper anchored in demo && not load (Score:3, Informative)
Re:Idle? (Score:3, Informative)
The videos clearly show that it isn't useful for keeping structure intact.
I disagree. The videos show me that the main failure mode of masonry walls is by 'folding' when the joins between blocks separate. This sheeting is very strong in tension, apparently, and prevents the block joints from opening to the point of causing the wall to tumble. I assume the results from a bomb overpressure wave would be similar to those from the wrecking ball.
Didn't they feature a similar experiment of one of those "Mythbusters" knockoff shows? IIRC, they used pickup truck bed liner sprayed on the test walls, and had similar results.
Re:Kevlar (Score:3, Informative)
"
This is definitely not intended as a complete history, but a brief summary and generalization. Still, the main point is that among other things, the bow and arrow drove the change from mail to plate armor, and then, with the development of the longbow, made that obsolete as well."
Uh, no. If anything, the price of plate mail, combined with gunpowder, made it obsolete. At Agincourt, the longbow shots were used to bog down the French knights in plate mail (and to score the occasional hit through an eye slit and on the mounts).
Longbows could sometimes penetrate plate, but only at close range and it also depended a lot on the quality of the plate mail and of the arrow.
Plate stayed around well into the gunpowder era, though not the full plate suits, but more the breastplate, helmet, demi-greaves (full plate on just the front of the legs), etc.
Breastplates during the English Civil War were "proven" by having a musket fired at them from 10 paces - you can see the dents on breastplates from this era in the Tower of London. (Hence the term bullet-proof.)
Various bits of full plate have been used all the way through the Napoleonic Wars and WWII, and is still rather effective against small arms fire, though the various modern kevlar and ceramic inserts are generally superior.
Re:Forget bombs, think hurricanes and tornados! (Score:3, Informative)
This is an issue that has been much debated, and to the best of my knowledge not yet firmly decided.
No, it is not an issue that has been debated. The practical aerodynamics of airfoils is very well settled.
If you have paid attention carefully when flying you may have noticed that a plane does not fly completely flat most of the time. There is a small angle between the planes wings and the direction of travel. Because air tends to follow the surface of the wing (sometimes called the Coanda effect) this means that the air gets deflected downwards by the wing. If the air accelerates down then by Newton's laws there is an equal and opposite force upwards on the plane generating lift so it can then fly.
1) This has little to do with the Coanda effect. 2) While there is momentum imparted onto the lower surface of a wing at a positive angle of attack, pressure distributions along the surfaces dominate the behavior of the airfoil. Air is slowing down when it follows the lower surface of a flat plate, and speeds up along the top, which gives (gasp) a pressure differential.
Re:Forget bombs, think hurricanes and tornados! (Score:2, Informative)
The reason for symmetrical wings on aerobatic aircraft is that they impede the flow even more and allow much greater control, at the expense of fuel efficiency.
Wanted to clarify this. The reason for symmetric airfoils on fighter aircraft is that camber provides no additional lift (compared to a flat plate) in a supersonic flow. Lift coefficient is still linearly proportional to angle of attack at supersonic speeds. However, drag coefficients rise quadratically with increasing camber/thickness. Thus, supersonic fighters have very thin, very symmetric airfoils. http://books.google.com/books?id=woeqa4-a5EgC&printsec=frontcover&dq=anderson+compressible#v=onepage&q=&f=false [google.com]
Re:Idle? (Score:3, Informative)
Re:Go big or lose your wall (Score:3, Informative)