Date:5 July 2012
They say dynamite comes in small packages…
Meet the mantis shrimp – a small, apparently harmless crustacean that resembles an armoured caterpillar and lurks in tropical waters. In reality, this creature is a real bruiser – and a heavily armed one at that. The 10 cm-long shrimp is equipped with a bright orange fist-like club that accelerates under water faster than a .22-calibre bullet. Repeated blows can destroy mollusc shells and crab exoskeletons, both of which have been studied for decades for their impact-resistant qualities.
A team of researchers at the University of California at Riverside Bourns College of Engineering believe military body armour and vehicle and even aircraft frames could be transformed by incorporating the unique structure of the shrimp’s club – a highly complex weapon comprised of three specialised regions that work together to create a structure tougher than many engineered ceramics.
The first region, located at the impacting surface of the club, contains a high concentration of mineral, similar to that found in human bone, which supports the impact when the mantis shrimp strikes prey. Further inside, highly organised and rotated layers of chitin (a complex sugar) fibres dispersed in mineral act as a shock absorber, absorbing energy as stress waves pass through the club. Finally, the club is encapsulated on its sides by oriented chitin fibres, which wrap around the club and keep it intact during these high-velocity impacts.
And that’s not all. The acceleration of the club creates cavitation, meaning that it shears the water, literally boiling it and forming cavitation bubbles that implode, yielding a secondary impact on the mantis shrimp’s prey.
Researcher David Kisailus and his collaborators are focusing primarily on improving military body armour, which can add 13 kg to a soldier’s load. Their goal is to develop a material that is one-third the weight and thickness of existing body armour.