June 12 (UPI) -- The evolutionary engineering of the mantis shrimp is inspiring a new class of lightweight, impact-resistant materials.
Some mantis shrimp species, called smashers, have a club-like arm capable of cracking clam shells. It can also be used as a weapon against rival shrimp.
Smashers live in coral reef cavities, and competition for prime real estate is fierce. To protect themselves from their peers, mantis shrimp have evolved an impressive shield built into their tail. The defensive component is called a telson.
To better understand the telson's defensive capabilities scientists modeled and tested both the shield's macro-scale architecture as well as its internal micro-scale structures. Their analysis showed the telson's helicoidal structure works to absorb energy and prevent cracks from forming and spreading.
Scientists likened the structure to braided plywood. It is the same structure scientists previously identified in the club-like arm of smashers.
"For over a decade, we have been studying the dactyl club of the smashing type of mantis shrimp," engineer David Kisailus, a professor at the University of California, Riverside, said in a news release. "We realized that if these organisms were striking each other with such incredible forces, the telson must be architected in such a way to act like the perfect shield."
There's always a limit to how much an animal can bulk up its defensive components. The shield can't be so heavy that it can't be quickly and effectively deployed.
"Having access to one the most efficient materials architectures, such as the helicoid, in conjunction with a clever geometry, makes this another winner solution found by nature," said Pablo Zavattieri, a professor of engineering at Purdue University.
The telson's helicoidal structure is accompanied by a series of curved ridges. Tests showed the structures, called carinae, also help absorb and dissipate energy.
"When we observed the carinae, it was obvious that they stiffened the telson along its long axis," Kisailus said. "However, we found that the carinae also allowed the telson to flex inward when forces were applied perpendicular to its long axis. This enabled us to discover the non-obvious function of these ridges, which was to absorb significant amounts of energy during a strike. Pablo's models then validated our hypotheses."
Scientists are currently working on using their discoveries -- described this week in the journal Advanced Functional Materials -- to develop impact-resistant materials that can be used in helmets, cars and other products.