Shrimp-inspired material to make airplanes stronger

Scientists have designed a composite material, inspired by mantis shrimp, that is more impact resistant and tougher than the standard material used in airplanes.
The material could be used in making aerospace and automotive frames, body armour and football helmets.
The peacock mantis shrimp, or stomatopod, is a 4- to 6-inch-long rainbow-coloured crustacean with a fist-like club that accelerates underwater faster than a 22-calibur bullet.
Researchers, led by David Kisailus from the University of California, Riverside are interested in the club because it can strike prey thousands of times without breaking.
The force created by the impact of the mantis shrimp's club is more than 1,000 times its own weight.

Previously, researchers have found the club is comprised of several regions, including an endocuticle region. This region is characterised by a spiralling arrangement of mineralised fibre layers that act as shock absorber.

In the new study, researchers applied that spiralled, or helicoidal, layered design when creating carbon fibre-epoxy composites.
Composites with this design structure could be used for a variety of applications, including aerospace and automotive frames, body armour and football helmets.
The researchers created carbon fibre-epoxy composites with layers at three different helicoidal angles ranging from about 10 degrees to 25 degrees.
They also built two control structures: a unidirectional, meaning the layers were placed directly on top and parallel to each other, and a quasi-isotropic, the standard used in the aerospace industry.

The goal was to examine the impact resistance and energy absorption of the helicoidal structures when they were struck and to quantify the strength after the impact.
Researchers used a drop weight impact testing system with a spherical tip that on impact creates 100 joules of energy.
This replicates testing done by the aircraft industry. Following the tests, they measured external visual damage, depth of the dent and internal damage by using ultrasound scans.
In the external damage category, the unidirectional samples split and completely failed. The quasi-isotropic samples were punctured through the backside and had significant fibre damage.
Although the helicoidal samples showed some splitting of fibres, they were not punctured completely through.

In fact, the dent depth damage to all of the helicoidal samples was 20 per cent to 50 per cent less than the quasi-isotropic samples.
The research was published in the journal Acta Biomaterialia.