Science

MIT breakthrough could lead to paper-thin bullet-proof armor

MIT breakthrough could lead to...
Edwin Thomas, left, and Jae-Hwang Lee holding a polymer material containing three bullets (Photo: Tommy LaVergne, Rice University)
Edwin Thomas, left, and Jae-Hwang Lee holding a polymer material containing three bullets (Photo: Tommy LaVergne, Rice University)
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An electron-microscope image shows a cross-section of a layered polymer and the crater left by a glass bead in an edge-on impact (Photo: Thomas Lab, Rice University)
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An electron-microscope image shows a cross-section of a layered polymer and the crater left by a glass bead in an edge-on impact (Photo: Thomas Lab, Rice University)
Edwin Thomas, left, and Jae-Hwang Lee holding a polymer material containing three bullets (Photo: Tommy LaVergne, Rice University)
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Edwin Thomas, left, and Jae-Hwang Lee holding a polymer material containing three bullets (Photo: Tommy LaVergne, Rice University)

Scientists have theorized that paper-thin composite nanomaterials could stop bullets just as effectively as heavy weight body armor, but progress has been hampered by their inability to reliably test such materials against projectile impacts. Researchers at MIT and Rice University have developed a breakthrough stress-test that fires microscopic glass beads at impact-absorbing material. Although the projectiles are much smaller than a bullet, the experimental results could be scaled up to predict how the material would stand up to larger impacts.

The glass beads, described as "millionths of a meter in diameter," are propelled using a laser pulse technique developed by MIT's Keith Nelson over several years. His technique was modified with the help of scientists from Rice University in experiments conducted at MIT's Institute for Soldier Nanotechnologies. Their work, reported in the journal Nature Communications, was supported by the U.S. Army Research Office, which is keen to reduce the burden on soldiers who currently wear armor that contains cumbersome plating an inch thick.

An electron-microscope image shows a cross-section of a layered polymer and the crater left by a glass bead in an edge-on impact (Photo: Thomas Lab, Rice University)
An electron-microscope image shows a cross-section of a layered polymer and the crater left by a glass bead in an edge-on impact (Photo: Thomas Lab, Rice University)

The team's self-assembling polymer is made by alternating flexible and rigid material layers just a nanometer thick, which can be seen clearly in cross-section with an electron microscope. This allows them to see precisely how the material has deformed after an impact. By studying multiple impacts, the team found that their material was 30 percent more resilient to head-on (rather than edge-on) collisions, a discovery which could change how current protective materials are made.

"It’s a novel and useful approach that will provide needed understanding of the mechanisms governing how a projectile penetrates protective vests and helmets," said Donald Shockey, director of the Center for Fracture Physics at SRI International (unaffiliated with the project), as quoted by David Chandler of the MIT News Office.

The researchers still need to develop a way to record these impacts in real time in order to best understand them, but their tests could accelerate the development of paper-thin military body armor or shielding for satellites, space suits, and shuttles, and more.

Source: MIT News Office

23 comments
mooseman
Good stuff! I wouldn't mind betting that when paper-thin body-armour comes along, it will probably use carbon nanotubes (which are much stronger and lighter than even steel.) I'm sure that they will eventually outdo ceramic armour too.
Dawar Saify
The problem with thin is that even if the bullet doesn't go through, the bullet will still do tremendous damage as a blunt impact causing external and internal bruising, therefore this has to be accompanied by other thicker layers which can be of light material, but by itself it is still dangerous.
Tankman
Anything that reduces the load on dismounts is great but there are a few issues that need to be addressed. In addition to stopping penetration, body armour and clothing needs also to address the blunt trauma injury caused by absorbing the energy from the strike. There is also performance against blast injury from IED to be considered. The rigidity of the armour will dictate how it is worn, either like the current plates or more like the steel armour of old, profiled to the body. There is likely to be the need for some energy absorbing material behind and this needs to be reconciled by heat management when the armour is worn in hot climates. Overall the soldier should end up with something much lighter and with as good or better protection but I hope developments will also make it more comfortable and less restricting and give dismounted troops back some of the mobility (together with the inherant protection that rapid movement provides) that they have lost in recent years.
Fusiontek
From the picture it looks like the glass 'bullet' tore a gaping hole, right through the armor. Am I looking at it, wrong?
Warhead
What everyone else says: The paper-thin armor might stop penetration, but it won't stop broken ribs or the blunt trauma. Some sort of lightweight ceramic plate armor in conjunction with this polymer sheet might help absorb and dissipate the impact.
bergamot69
In regard to stopping blunt object inflicted injuries, all that would be required would be some means of keeping the armour a little distance from the skin- eg selective padding, rubber cones, etc. Additionally, having the armour held away from the skin could mean that some form of simple ventilation system could be employed to keep the soldier cool- I hate to think how much those guys must sweat in the heat of Afghanistan or Iraq.
PeteKK
Why not just use good old empirical data? Fabricate a few different materials and fire some bullets into them. That way the material gets out into the marketplace where it can be utilized and the over focused PhD's can figure out the "why it works" details later. I wonder how far behind we'd be if we just discovered iron and it was up to the guys at MIT to determine why it's able to cut through wood before we made a saw.
GadgetGeek
“inability to reliably test such materials against projectile impacts” What? Give me a Barrett 50, an M-16, AK-47, and maybe a few exotics like the Steyr AUG and FN-SCAR…and limitless access to military and civilian ammunition… and a few “sheets” of this stuff and I will test it for you… has to be a lot simpler than setting up a pulse laser to propel microscopic glass beads for crying out loud… I get that they want to look at this material from the most scientific and molecular level but for crying out loud… analysis paralysis anyone… does it stop a bullet or not… how big… with what kinds of “tips”…what backing does it require to not kill the wearer due to the energy transfer on the backside… Throw some lead at it and Get’er done!
Jim Sadler
The better solution is robotic war where soldiers are no where near any harm. I know that robotic air craft are now common enough and the Navy will soon have very potent unmanned ships. The foot soldier remains the largest challenge for robotics. Supposed critics make noise about innocents lost in conflict. The normal slaughter of innocents is about 20-25% of all killed in war. So far robotic- drones have a far better gentleness to uninvolved parties.
Rion Rion
RE: Blunt trauma: Wrong. Merely adding a puncture-proof layer of "paper thin" material over, say, a standard BDU, provides plenty of room for even the minute resistance of air trapped between the material and the body to slow the projectile (and the material itself) down to acceptable levels. The average bullet, whether pistol or rifle, has less kinetic energy than a decent fastball. The difference is it's really light, really small, and going wickedly fast, so you the timescales of interaction change from "oh, i need to catch that" to "oh, i was shot... and now i'm bleeding to death..." So, extending the duration of the impact event from microseconds to milliseconds, turns a Gigawatt interaction into a longer, but lower power megawatt or tens-of-kilowatts interaction. Nobody's getting liquefied. Things do change with a .50 BMG... that's more or less the kinetic energy of a full size pickup being dropped on your chest from about ten-twelve feet up. *Splat*