Next time you throw some shrimp on the barbecue, remember one thing — those crustaceans could one day save your life.
Scientists at the University of California, Riverside, are studying military applications for one species in particular — the peacock mantis shrimp, whose hammer fists may unlock secrets to better protection for ships, planes, Humvees and personal armor.
The colorful, 4-inch-long shrimp, located in tropical waters, is notable for its bright-orange, fist-like appendages that can smash through clam shells, small fishes’ skulls and even aquarium glass at 45 mph underwater with 200 pounds of force, according to lead researcher David Kisailus. The shrimp can punch about 50,000 times over a span of about four months before the limb is injured, at which point it can grow a new one.
Kisailus and his team are trying to replicate the lightweight, impact-resistant qualities of the shrimp’s club.
When he began looking at the mantis shrimp’s hammer-fist in 2007, Kisailus said he intuitively saw military applications because of the impact the structure can withstand. One application is the design of shock-resistant body armor to prevent internal injuries.
He also said the material could be used for helmets to prevent concussions.
In addition to body armor, the new material could also be used to replace the steel plates that are mounted above the guns on a ship’s deck to provide added protection from enemy fire, he said.
Kisailus has sent a proposal to the Office of Naval Research Young Investigator Program, which awards up to $170,000 per year for up to three years to an institution. He has not received a response.
The U.S. Air Force Office of Scientific Research has provided $600,000 to support Kisailus’ research, according to a university news release.
“If you can get the structure down and understand how it all works together to mitigate not only that initial impact, but repeated impacts, then you can think about incorporating this type of material into something you want to protect, like an armor,” said Hugh De Long, director of math information and life sciences at the Air Force office.
The key to designing this protective material is replicating the three-part structure of the club, according to researchers. The outermost section is made of hard crystalline minerals and acts like your knuckles when throwing a punch, Kisailus said. The layer behind that is made of softer organic material and is designed to absorb impact. These fibers are arranged with layers stacked on top of each other in a shape similar to rotini pasta.
The third part of the club is called the striated layer and is made of fibers running parallel to each other wrapped around the club, like “a boxer that puts tape around his fists,” Kisailus said.
He and his team have begun testing a prototype composite plate made of epoxy and fiberglass that stopped bullets, but weighed less than steel plates.
In addition to personal protection, the technology could be used to extend the life of Navy ships. When the mantis shrimp strikes its prey, the club moves so fast through the water that tiny bubbles appear, called cavitation, imploding against the prey, but causing no damage to the shrimp itself. If researchers can figure out why, it may lead to advancements in how to prevent cavitation damage on ships’ propellers.
Kisailus said the idea could be applied to Humvees as well, better protecting against improvised explosive devices, or protecting UAVs or helicopters against enemy fire.
“It’s more for close-ground support,” De Long said. “We think about using this on a helicopter because they are close to the ground or our A-10 [Thunderbolt] aircraft, which has that titanium shell inside of it. We could replace the titanium with this to protect it against round impact.”
Kisailus said he expects a refined model of the material to be available in two to three years for testing by the military. In the future model, the cheap epoxy and fiberglass used in the prototype could be replaced with strong engineering materials such as carbon fibers.