SOLDIER ARMOR: STEP INTO LIQUID

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.

April 25th, 2004 | Armor | Comments Off Both comments and pings are currently closed.