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Blast-Proof Fabric Resists Multiple Explosions
An anonymous reader tips a Gizmodo story on a fabric whose properties are counterintuitive, to say the least of it. "Zetix is a fabric so strong it will resist multiple car bomb blasts without breaking. It absorbs and disperses the energy from explosions... it can be used in body armor, window covering, military tents, and hurricane defenses... [and] it can be used as medical sutures that won't damage body tissue. All of this is thanks to a property that apparently defies the laws of physics: helical-auxetics, objects that actually get fatter the more you stretch them. The concept makes my head want to explode, but when you see it in action it actually makes sense."
Oh yeah, video of the dragon skin grenade test here
Nice video showing and explaining the phenomenon: http://www.youtube.com/watch?v=vdkYuLsT7Sc
Armor is not just a single layer of stuff, it is multiple layers. Yes, this stuff by itself is not worth much as armor, but layer it on top of other thigns, and you got something special.
Each layer stops something else. This layer does not break, so it stops penetration. Make a cell structure of this, fill it with something else, like say SAND, and that pressure wave you were so worried about becomes contained. Two layers of a cell structure like this, with sand in between them, and the entire explosive kinetic energy is contained, converted to heat, deflect out, or otherwise dealt with.
excitingthingstodo.blogspot.com
Funny, I was hit with shrapnel while wearing Kevlar and am still breathing. If I had not been wearing it i would never have survived. The secret to armor is layers, it may get through the first few layers but it isn't going to slice through the whole suit. The flexibility actually helps to protect you by dispersing the energy across a larger area than the surface of the object striking you. Your cup / box analogy is the stupidest example you could have thought of. How about adding a form fitting cushion around the cup and then hitting it. The box and cushion will absorb a lot of energy (by flexing) before the cup breaks.
Force times distance is WORK, not energy. Can you explain the energy of a photon in terms of "force times distance?" Nope.
What matters in this application isn't energy, but momentum. If the fabric could dissipate ALL the kinetic energy of an explosion/bullet as heat, that would be remarkable but not enough. You can't "dissipate" momentum, regardless of what crazy cool materials you come up with.
In the case of a blast shield covering a window, the strength of the fabric against tearing will allow it to transfer the momentum of the explosive blast to the structure of the building instead of allowing it to blow in through the window. But that only works because the fabric is anchored to the building. Wearing such a fabric will prevent debris from penetrating your body but it will not protect you from the concussive force of an explosion or the raw momentum of a bullet.
People have died from internal injuries after being shot while wearing a bullet proof vest. The bullet was "stopped" in a sense, in that it didn't actually ENTER the victim's body but the momentum still kills.
These materials seem to behave in similar ways as olivene (and some pyroxene's). The chemical bonds bend in certain ways when force is applied in a prefered direction.
And remember, energy dissapation is the sum of all those bonds moving in response to the force applied. A few hundred billion bonds, just moving a tiny bit each, adds up to a lot of energy.
Have a tissue, I think your nose must be stuffy.
A 160 grain bullet fired from a 30 caliber rifle at 3000 fps (those are rough numbers, and on the high side) has the same momentum as a 175lb man traveling at .4 fps. Momentum is not an issue.