Questions concerning shear-thickening fluids

[Elok]

All right, so I've read some arms-research-for-dummies articles about this stuff; for those that haven't, apparently various corporate/government entities are researching new types of body armor filled with goo which becomes rigid in response to sudden impacts. So, the idea is that you can run around in a relatively lightweight and flexible suit, but the moment somebody shoots or stabs you the goo stiffens up, stopping the advance of the attack and spreading the impact out over a wider area of one's body. Then it softens again so you can move around. http://en.wikipedia.org/wiki/Dilatant#Body_armor gives a brief synopsis.

So much I get. But I'm interested in the nitty-gritty. Does anyone here know of a site that discusses this stuff in a knowledgeable but not impenetrably technical manner? I'm particular curious about things like:

-Presumptively the knife/bullet can still potentially cause a hole in the container, which would allow for leaks--is this correct? Would a long, slashing impact lead to massive goo loss even if the subject wasn't injured (assuming you don't pad it with kevlar or another such material)?
-How much protection would such armor offer against broader-surface impacts, e.g. bomb blasts? I'm guessing "not much" in the case of a blast that sends a guy flying, though it would block shrapnel.
-I'm sure a sufficiently strong force could penetrate the protection; how strong, do you suppose? EDIT: By "penetrate" I mean punch through and hit the body beneath, not magically nullify the thing's force-distribution properties or anything. I mean, presumptively if you shot a .50 cal sniper rifle into one of these things the bullet would go through, but how much weaker would the shot have to be before the projectile wouldn't get through?

I would just Google it, but I'd like information that might have a prayer of being accurate. And there's no English-language library down here.

Thanks in advance to anybody nerdy enough to speculate on this stuff!

[Felch]

Mix corn starch and water. It's similar goop. If you slap it, it stays hard, but if you slip your fingers into it, they move right through.

Most ballistic armor is not effective against knives. They use special stab vests where knife attacks are a greater threat than bullets, like prisons. My guess is that a knife would be slender and slow enough to get through the goo.

Broader impacts, like bombs, are generally hard to protect against. Bomb squad guys wear full body suits. Generally, if a bomb throws you, it's also turning your brains to mush.

The best armor around today, type IV, is supposed to stop a 30-06. That's a hefty bullet, but it's nowhere near the power of a .50 BMG.

Any information that's publicly available is probably obsolete.

[SlowwHand]

Elok, you never cease to amaze me.

[loinburger]

I asked my brother if he knows anything about this since he's a "materials scientist," but he said that if it's not a logic gate then he knows ****all about it.

Regarding leaks, if I were designing the thing I'd have multiple overlapping packets of the goo (sort of like overlapping sheets of bubble wrap) - even if a few of the packets were punctured you wouldn't lose all of the goo (although the site of the puncture probably wouldn't be very bullet-resistant)

[Elok]

Fun times! Thanks to all three of you, including Sloww for what I choose to interpret as a compliment.

[Zoetstofzoetje]

wow, this would be good stuff for on the motorcycle.

i looked it up:

This transformation is possible due to the way these unique molecules move with each other. When the material is being moved at low speed it is soft and flexible, because the bond between the molecules is not that strong, so they can slip past each other. Yet when the material is asked to move quickly by a sudden hard force the molecules re-arrange themselves in a very structured way and create proper hydrogen bonds. So in other words, when you impact the molecules they do not have time to move and they quickly lock into position

[Zoetstofzoetje]

GOOD STUFF

thinking about it though, this will not protect me significantly better from the biggest danger on a motorcycle: breaking your neck. it´s just more comfortable.

[Tupac Shakur]

If you slap it, it stays hard, but if you slip your fingers into it, they move right through.

Jesus, this sounds so dirty.

[Main_Brain]

Presumptively the knife/bullet can still potentially cause a hole in the container, which would allow for leaks--is this correct? Would a long, slashing impact lead to massive goo loss even if the subject wasn't injured (assuming you don't pad it with kevlar or another such material)?

I dont really think that would be problematic. Self Sealing Fuel Tanks have been around since WW2, most likely a similiar technology could be used here.

More interesting would be the Shock dispersion in the Fluid. Assuming multiple impacts and a certain reaction time before the Fluid turns rigid my limited knowledge of Wave Mechanics tells me the Interference could lead to some quite interesting visual effects