Bullet strikes the nanotube at a relative height of 0.31
(a) with both ends fixed and (b) with one end fixed.
Posted on 11/23/2006 12:05:52 PM PST by LibWhacker
(Nanowerk Spotlight) Carbon nanotubes (CNTs) have great potential applications in making ballistic-resistance materials. The remarkable properties of CNTs makes them an ideal candidate for reinforcing polymers and other materials, and could lead to applications such as bullet-proof vests as light as a T-shirt, shields, and explosion-proof blankets. For these applications, thinner, lighter, and flexible materials with superior dynamic mechanical properties are required. A new study by researchers in Australia explores the energy absorption capacity of a single-walled carbon nanotube under a ballistic impact. The result offers a useful guideline for using CNTs as a reinforcing phase of materials to make devices to prevent from ballistic penetration or high speed impact.
Professor Liangchi Zhang from the School of Aerospace, Mechanical and Mechatronic Engineering at the University of Sydney explained the new research to Nanowerk: " Especially in making bullet-proof vests, shields, and explosion proof blankets, the best protective material will have a high level of elastic storage energy that will cause the projectile to bounce off or be deflected, i.e., the objective is to reduce the effects of 'blunt trauma' on the wearer after being struck by a bullet. We therefore tried to understand the impact behavior of CNTs."
Zhang published his recent findings, titled "Energy absorption capacity of carbon nanotubes under ballistic impact", in the September 18, 2006 issue of Applied Physics Letters.
Zhang's study analyzes the impact of a bullet on nanotubes of different radii in two extreme cases. For a nanotube with one end fixed, the maximum nanotube enduring bullet speed increases and the energy absorption efficiency decreases with the increase in relative heights at which the bullet strikes; these values are independent of the nanotube radii when the bullet hits at a particular relative height. For a nanotube with both ends fixed, the energy absorption efficiency reaches minimum when the bullet strikes around a relative height of 0.5.
Bullet strikes the nanotube at a relative height of 0.31
(a) with both ends fixed and (b) with one end fixed.
"Specifically, we investigated the relationship between the nanotube radius, the relative position at which the bullet strikes, the bullet speed, and the energy absorbed by the nanotube for a particular bullet size and shape" says Zhang.
A piece of diamond having 1903 atoms was used as a bullet with its speed varying from 100 to 1500 m/s. The bullet dimension was selected such that the width is larger than the width of the biggest nanotube after flattening. The bullet was released from a target about 15 Â from the center axis of the nanotube and moved at a constant speed in the horizontal direction i.e., perpendicular to the nanotube axis, as shown in the graphic above. The nanotube performance was examined for bullet released with various speeds at various positions using the classical molecular dynamics method.
In his experiments, Zhang found that, for a nanotube with one end fixed, the CNT could be resilient to projectile traveling at speeds of 200–1400 m/s (for comparison, the initial velocity of modern rifle bullets is somewhere between 180 and 1500 m/s, depending on gun and bullet type. For a typical over-the-counter gun the speed is below 1000 m/s); the nanotube enduring projectile speed increases whereas the absorption efficiency decreases with the increase in relative height ρ. For a nanotube with both ends fixed, the absorption energy reaches maximum whereas the absorption efficiency reaches minimum when the bullet strikes the nanotube in the middle.
Zhang is excited by the great potential offered by CNTs in making ballistic-resistance materials and his research in this area is ongoing: "We'll continue to try to understand the impact behavior of CNTs under more complicated loading conditions."
This would be totally unnecessary if we had safer bullets.
I'm Jocelyn Elders and I approved this message.
Bulletproof underwear, that's the future.
These type inventions concern me because of their potential to make the 2nd amendment obsolete. Just wait and see what happens when the politicaians think they can screw with the public with no consequences.
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So if I understand this correctly, the bullet would push the fabric into the body causing all kinds of damage, but the fabric won't break?
What am I getting wrong here?
Could be wrong, but I'm assuming the nanotubes spread out the energy of the impact over the whole shirt.
My guess is that a really bad bruise is usually going to be better than a perforation and a large exit wound.
This guy could have used such.
"Could be wrong, but I'm assuming the nanotubes spread out the energy of the impact over the whole shirt."
I don't think so. As such, even if it could prevent a slug from getting through the material, it would create some massive trauma at the point of impact and hurt like all get out. OTO, you would likely live to fight another day.
This is going right into the novel I'm writing. HooYah
Well, the next logical step would be exotic bullets [say, with no spin - aerodynamic stabilization with fins and long boattail, but with a small shaped charge. Impact velocity will be 8000m/sec or better]. Similar game was played by Krupp ages ago. Better armor plate - and then better artillery shell, and then still better armor plate, and again, still better shell... The Kaiser saw it right through, but had to pay from both ends anyway.
Precisely ... the fabric may not allow the projectile to penetrate ... but the material is so thin it will allow the projectile to push the fabric well into the body tissue.
Hi, Jocelyn, still using cornhuskers on your hands?
Really love a story that has might, and could, and maybe. Give the guy a few million and he might, could, may have something.
As far as I know, we still can't make transparent objects out of this stuff. So, as we do in games like Halo when the enemy has body armor that you can't get through, go for faceplates.
Only if they wear this underwear over their head and face.
I have all the other pieces to my outfit ... cape, tights, belted speedo, boots ...
Being shot in the groin would still be one hell of kick in the balls. All that bullet's energy has to go somewhere. If this happened to you, you might wish you were dead for awhile.
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