Military

Graphene could find use in lightweight ballistic body armor

Graphene could find use in lig...
A rendering of a 3.7 micron-wide "microbullet" hitting a sheet of graphene, which deforms to absorb much of its kinetic energy (Image: Jae-Hwang Lee/Rice University)
A rendering of a 3.7 micron-wide "microbullet" hitting a sheet of graphene, which deforms to absorb much of its kinetic energy (Image: Jae-Hwang Lee/Rice University)
View 2 Images
A rendering of a 3.7 micron-wide "microbullet" hitting a sheet of graphene, which deforms to absorb much of its kinetic energy (Image: Jae-Hwang Lee/Rice University)
1/2
A rendering of a 3.7 micron-wide "microbullet" hitting a sheet of graphene, which deforms to absorb much of its kinetic energy (Image: Jae-Hwang Lee/Rice University)
A microbullet traveling at supersonic speed is captured in this composite of three timed images, as it makes its way toward a suspended sheet of multilayer graphene (Image: Thomas Research Group/Rice University)
2/2
A microbullet traveling at supersonic speed is captured in this composite of three timed images, as it makes its way toward a suspended sheet of multilayer graphene (Image: Thomas Research Group/Rice University)

While graphene is already known for being the world's strongest material, most studies have focused on its tensile strength – that's the maximum stress that it can withstand while being pulled or stretched, before failing. According to studies conducted at Houston's Rice University, however, its ability to absorb sudden impacts hadn't previously been thoroughly explored. As it turns out, the material is 10 times better than steel at dissipating kinetic energy. That could make it an excellent choice for lightweight ballistic body armor.

The research was led by Rice materials scientist Edwin Thomas and assistant professor Jae-Hwang Lee of the University of Massachusetts, Amherst.

For their small-scale tests, they used sheets made up of multiple layers of graphene. These were stacked together and held in place in a stage mount. Although up to 300 layers were used at a time, the total thickness of the sheets ranged from just 10 to 100 nanometers – keep in mind that each layer was just one carbon atom thick.

They then shot microscopic spheres into those sheets, at speeds of up to 3 km (1.9 miles) per second. The scientists did so using an advanced version of a technique that they had developed previously, in which a laser pulse is fired onto one side of a gold surface, causing so-called glass "microbullets" to fly off the other side at high speed.

A microbullet traveling at supersonic speed is captured in this composite of three timed images, as it makes its way toward a suspended sheet of multilayer graphene (Image: Thomas Research Group/Rice University)
A microbullet traveling at supersonic speed is captured in this composite of three timed images, as it makes its way toward a suspended sheet of multilayer graphene (Image: Thomas Research Group/Rice University)

When these bullets hit the graphene, it deformed into a cone shape around them before ultimately breaking and letting them through. In the three nanoseconds before it broke, however, the deforming graphene absorbed a huge amount of the bullets' kinetic energy – the scientists estimate that the transferred energy traveled through the material at a speed of 22.2 km (13.8 miles) per second, which is faster than any other known material.

"The game in protection is getting the stress to distribute over a large area," said Thomas. "It’s a race. If the cone can move out at an appreciable velocity compared with the velocity of the projectile, the stress isn’t localized beneath the projectile."

He now plans on demonstrating that if scaled up, graphene sheets could be used in applications such as bulletproof body armor, or even in coverings that would help protect spacecraft from high-velocity orbital debris.

A paper on the research was recently published in the journal Science.

Thomas describes the research in the video below.

Source: Rice University

Microbullet hits confirm graphene's strength at Rice University

3 comments
Doug Doyle
I would be more impressed, and not think of this as a pie in the sky if they did the testing with modern pistol caliber rounds.
lwesson
I agree with Doug Doyle. Just how difficult would it be to make something to test this in a real world application? Talking about a Real World, the Rice guys and gals will be looking at the actual language used in the ballistics per bullets, and the pistols used. Grains of lead, and feet per second... Grams are too large, as are meters. But my guess the science wonks at Rice U. will choke on such, as well as getting near anything as nasty nasty as a gun. The area around Rice University is quite Liberal and well heeled -$$$-. I know the location very well. People would be fainting if they knew such ballistic tests were being conducted on campus. I can see such material coming though. One serious problem that will be faced, will be countering the violent effect of mass suddenly being slowed to a stop and making a sizable dent. Dents hurt. Body shock can kill. The science of this has been well studied. Rice scientists would be well served to team up with current body armor & helmet makers. Humm? Applied to Killer Robots then...
John Whiting
It works well at the nano scale. I agree with Mr. Doyle that it ought to be interesting to see how well it does at the macro scale. Something they haven't addressed, and might not be able to address until they scale up, is how well it protects against edged weapons. Kevlar is good against bullets, but cuts and therefore is ineffective against knives. An inability to be cut makes for a better shield, but would complicate the manufacturing process for specific items and shapes. I tend not to think of early advanced research as "pie in the sky" because it is literally too early to determine what the discovery is good for. Certainly the original pulsed ruby laser would have seemed like pie in the sky, with its huge inefficiencies and inability to form a non-pulsed beam. However, lasers, pulsed and otherwise, have proven to be enormously useful, with new uses still being discovered. This mesh is still at the ruby laser stage. Let's see what develops as the technology grows up a little.