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Nature as a model: skeletons and fish shapes inspire carmakers

It's true that quite a lot has happened since the invention of the car in 1886. But compared to four billion years of evolution, that's barely more than the blink of an eye. Nature often has much better solutions.

Is this design or can it go? When Klaus Millerferli holds the damper domes of the new Mercedes EQXX in his hands, you might think he's made a mistake.

The bulky and unstructured metal part looks more like a trash can than avant-garde. And it's hard to believe that the front axle of the electric technology carrier is supposed to be supported by it.

But Millerferli cradles the casting in his hand with the greatest appreciation and is delighted with its low weight and airy shape. Because not only is it extremely stable, it also weighs four kilos less than a conventional component.

Created according to the model of nature - carbon skeletons

"To do that, we designed it based on nature," says the engineer. Instead of being developed on the drawing board with the same software on the computer that is used to generate the monsters for computer games - not drawn, but literally grown - it therefore looks like a skeleton.

And just like the bones of humans or animals, the structural part is extremely strong at the crucial points, but does not need excess material anywhere and is therefore particularly light.

In doing so, Millerferli is following a trend that is currently very popular among car developers. In the struggle to achieve the lowest possible weight and maximum range, they are taking their inspiration from nature. This is particularly evident in the Mission R, with which Porsche is giving shape to the electric race car of the future.

Instead of constructing a frame and then cladding it with a body, the two-seater carries a carbon skeleton that is visible from afar and whose gaps, open like a truss, allow quite unusual views in and out - especially on the roof.

"This is where form and function come together in a perfect way," says designer Peter Varga. "Because this so-called exoskeleton is not only particularly light and stable, it also looks spectacular."

Turtle and the skull of a dinosaur

Others had this idea before Porsche: At the development service provider Edag in Wiesbaden, for example, there is the Genesis technology carrier. Its body is modeled on a turtle shell from the 3D printer.

Or the sporty two-seater from the Fraunhofer Institute for Manufacturing Engineering and Automation (IPA) in Stuttgart. To ensure that it actually weighs less than 500 kilos and still offers sufficient accident protection, the skull of the Simosaurus had to serve as a model for its body structure.

Finally, the researchers found some interesting parallels: During the hunt, the bone was stressed in the same way as the chassis when driving over a bumpy slope. And when the jaw snapped shut while eating, similar forces acted as in a crash, the IPA experts explain.

Waddling on land and elegant on the water

In addition to lightweight construction and safety, it's aerodynamics that takes its inspiration from nature. "Because when it comes to flow resistance, evolution has already produced some sensational shapes," says Teddy Woll, who presides over the wind tunnel at Daimler. The penguin, for example.

On land, he may seem slow, and his gait is neither efficient nor aesthetic. "But in the water, no one can fool it," says Woll, who could go on for hours about birds and fish. So it's no wonder that some of the details of our cars resemble wings or fins, or that the entire shape emulates a fish.

However, there are also limits, especially in the conflict between aerodynamics and aesthetics, Woll admits. He recalls the boxfish that became the model for the Swabians' bionic car in 2005. The fish is particularly aerodynamic, and the car inspired by it is incredibly efficient, with a Cd value of 0.19. But it's not the fish that's the problem.

But beautiful is a different story. Although perfectly suited to a compact van or SUV, this shape is therefore unlikely to appeal to broad public taste - and has long since disappeared back into the designers' evidence room.

Lotus blossom effect for clean toilets and tire sidewalls

Body frames like a bone skeleton, grown structural parts and design lines like fish bodies - as new as these ideas may be, bionics is old hat. Whether it's cars, aviation or household technology, nature has been providing the model for practical achievements since time immemorial.

One of the most popular examples of the transfer from nature to the factory is the so-called lotus blossom effect, with which the leaves of the plant have become resistant to dirt.

Researchers have also been able to transfer the principle of the small nubs, which are responsible for water and thus also dirt particles beading off the surface of the plant, to artificial surfaces. This ensures that sinks and toilet bowls are always clean. This is a property that paint manufacturers hope will soon make car washes superfluous and tire manufacturers hope to keep the sidewalls of their tires clean.

Efficient shark as a model for more efficient cars

But it's not only flowers that inspire researchers, but even fish scales. A few years ago, for example, BMW researchers took a close look at the skin of the shark. Special profiles can reduce frictional resistance by up to three percent.

The idea was that if these profiles were transferred to a film and glued to the sheet, fuel consumption could be reduced accordingly. However, the Bavarians did not pursue this idea any further.

This is not unusual, because bionic ideals often clash with other requirements for the car - be it costs, implementation in production, or simply taste: "Not everything that bionics tells us to do in design, for example, would appeal to consumers," says Mercedes aerodynamicist Woll, recounting the ongoing constructive dispute with the designers.

This does not mean that bionics has been written off. On the contrary, existing development approaches are not always able to take account of the many challenges currently facing the automotive industry. That's why people are specifically looking for solutions in other industries, including bionics: "Bionics provides interesting inspiration and approaches to solutions," says BMW spokeswoman Julia Jung, for example.

Source: Skeletons and fish shapes inspire carmakers / Nürnberger Nachrichten (18.10.2022)

Tom Illauer

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