And researchers are now revealing how that is possible.
A remarkable beetle lives in arid regions on the west coast of the United States. It’s about the Nosoderma diabolicum, a family beetle Zopheridae. And it has such a strong armored shield that it does not even budge if a car drives over it.
The beetle has astonished many scientists. But the big question is of course how it is possible that this rather small beetle has a very strong shell. The researchers decided the Nosoderma diabolicum research in the laboratory and then apply extensive computer simulations and 3D models. And in the end, the researchers managed to unravel the mystery of the very strong armored shield of the special beetle.
The researchers found that the armored beetle can absorb about 150 newtons (15 kilos) – a load of at least 39,000 times (!) Its own body weight – before breaking in two. And that is very impressive. A car tire exerts a force of about 100 Newtons (10 kilos) when it drives over a beetle on a dirty surface. Other beetles the team tested couldn’t handle even half the force that the miraculous one Nosoderma diabolicum can resist.
How the Nosoderma diabolicum get this done? Flying beetles have elytra – or thickened and hardened forewings that have been turned into shields – to protect the underlying hind wings and rear body. In addition, they can take off more easily thanks to the elytra. The Nosoderma diabolicum however, has no wings. Instead, the elytra click together, as it were. These elytra meet in a line called a suture that runs the entire length of the abdomen. “This suture is actually a kind of jigsaw puzzle,” explains researcher Pablo Zavattieri. “It connects the different sheets – the puzzle pieces – with each other.” And this ensures that the applied force is more evenly distributed over the body, allowing the beetle to absorb a lot of heavy kilos.
That is how it works
This jigsaw puzzle comes in handy in a variety of ways depending on the amount of force applied. First of all, the interconnected sheets are ‘locked’ to prevent them from being pulled out of the suture. In addition, the blades are very flexible, so that they can be easily transformed and the ‘puzzle pieces’ can easily let go of each other. This reduces the chance that the whole will break. If they interlock too much or too little, the sudden release of energy would cause the beetle’s neck to break (see also the video below).
The beetle is a great source of inspiration for the development of new materials that have the same unbreakable properties. These materials would be stiff, but flexible, just like a paper clip. This can make machines such as gas turbines in aircraft safer and more sustainable, according to the researchers. At present, in gas turbines, metals and composites are connected with each other with a mechanical seal. This closure adds weight and creates tension, which can lead to breakage and corrosion. “These fasteners eventually degrade system performance and need to be replaced every now and then,” says researcher Maryam Hosseini. But the Nosoderma diabolicum has devised smart strategies to get around these limitations. “The armored beetle suture is very robust and this could help solve existing problems,” said Hosseini.
The researchers built in the study the suture of the Nosoderma diabolicum and then conducted experiments with it. This shows that this closure is as strong as a standard aviation fastener, but much more difficult to break. “Our work shows that we can potentially switch from using strong, but brittle materials to materials that dissipate energy when they are likely to break, and so are both strong and resilient,” Zavattieri concludes. “That’s what nature does with the Nosoderma diabolicum did.”
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