Mantis shrimp inspires new body armour and football helmet design
18 June 2015
The spiral structure of the mantis shrimp's club, which it uses to crush the shells of prey, inspires new composite materials for a range of impact resistant applications.
The mantis shrimp is able to repeatedly pummel the shells of prey using a hammer-like appendage that can withstand rapid-fire blows by neutralising certain frequencies of 'shear waves', according to a new research paper by University of California, Riverside and Purdue University engineers.
The club is made of a composite material containing fibres of chitin, the same substance found in many marine crustacean shells and insect exoskeletons but arranged in a helicoidal structure that resembles a spiral staircase.
This spiral architecture, the new research shows, is naturally designed to survive the repeated high-velocity blows by filtering out certain frequencies of shear waves, which are particularly damaging.
The findings could allow researchers to use similar filtering principles for the development of new types of composite materials for applications including aerospace and automotive frames, body armour and athletic gear, including football helmets.
"This is a novel concept," says UC Riverside's Professor David Kisailus. "It implies that we can make composite materials able to filter certain stress waves that would otherwise damage the material."
The 'dactyl club' can reach an acceleration of 10,000G, unleashing a barrage of impacts with the speed of a .22 calibre bullet.
The researchers modelled the structure with the same mathematical equations used to study materials in solid-state physics and photonics, showing the structure possesses 'bandgaps' that filter out the damaging effects of shear waves travelling at the speed of sound.
These findings appear in a research paper published online in the journal Acta Biomaterialia.