The Secret to Engineering Tougher Armor May Lie In The Mantis Shrimp’s Claw
By Lenny Pierce on April 28, 2014
Scientists are already trying to harness the durability of oyster shells to develop bullet proof windshields of military vehicles, and now they’re turning to the mantis shrimp’s shell in designing the rest of the Humvee. The mantis shrimp hunts by punching its prey with two hammer-like appendages that snap forward with the speed of a .22 caliber bullet, meaning that whatever covers these body parts must be incredibly durable if it is to hold up over the shrimp’s life time. In the ongoing quest to develop stronger and stronger building materials for planes, cars and body armor, scientists at the University of Riverside decided they need to figure out how these fists stayed intact after a lifetime of dealing the hardest hits in the ocean.
To give you an idea of the punch these guys pack, watch this specimen beat the hell out of a clam:
As it turns out, the punching-claw’s covering consists of several layers of mineralized fiber. Each layer is arranged at an angle to the last so that at any given impact point, there is a spiral structure that effectively dissipates the impact. The photo below shows a cross section of how these layers are arranged:
The spiraling structure of the mantis shrimp’s claw covering. (University of California Riverside)
To figure out exactly how the this spiraling pattern absorbed shock so well, researchers engineered some fiber-epoxy composite layers and stacked them on top of each other. They laid each layer at a specific angle to the one beneath it – the angles ranging from 10 to 25 degrees – to see which arrangement provided the strongest stack of layers. What they found was that the arrangement that held up the best was by far the one most similar to that found in the mantis shrimp’s claw.
Below is a video from the Smithsonian Channel showcasing the mantis shrimp’s punching power. Unfortunately, there is no evidence that the claw actually makes a movie-quality shotgun cocking noise when it’s preparing to fire:
Here’s a mind blowing side note. The mantis shrimp’s punch moves so fast that it actually boils a small section of water, creating a cavitation bubble that collapses a split second later. This process creates a shock wave that can be equally deadly to whatever prey item is standing in front of it. So even if you manage to somehow dodge the speeding upper-cut, the mantis shrimp’s ability to master cavitation will still knock you on your ass – or tail fin, as the case may be.