Calling a G.I. mushy in the middle may not be such an insult, soon. Because Army researchers are working on liquid body armor, to add to soldiers' bulletproof vests.
The key component of liquid armor is a shear thickening fluid. STF is composed of hard particles suspended in a liquid. The liquid, polyethylene glycol, is non-toxic, and can withstand a wide range of temperatures. Hard, nano-particles of silica are the other components of STF. This combination of flowable and hard components results in a material with unusual properties.
"During normal handling, the STF is very deformable and flows like a liquid. However, once a bullet or frag hits the vest, it transitions to a rigid material, which prevents the projectile from penetrating the soldier's body," said Dr. Eric Wetzel, a mechanical engineer from the [Army Research Lab's] Weapons and Materials Research Directorate who heads the project team.
It all sounds pretty unlikely. But there's a simple demonstration of how this works, a Slashdot contributor says.
"Make a wet paste of cornstarch. You'll notice if you take a stick or even your finger and stir it around very slowly... it will act like a viscous liquid. It flows around your stick and the path left in the paste slowly fills back in. Now try moving the stick quickly through the paste and it suddenly becomes solid, the wet gloss of it's surface disappears, and the paste cracks and breaks like a hard material. Literally the force applied to the paste shifts it from liquid to solid state and upon release of stress it becomes liquid again. "
A scientific paper on liquid armor, from Wetzel & Co., is here. And here's an article I wrote a while back on related research, from MIT's Institute for Soldier Nanotechnologies.
THERE'S MORE: The new-fangled armor is like silly putty -- or the inverse of ketchup. DefenseWatch explains.
