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A New Type of Steel that Bends Like Bamboo

Steel is the world’s dominant commercial building material for plenty of reasons: strength, ductility, and malleability, to name just three. But what if steel could be improved, not just by the latest technology, but also by taking a page from nature? Scientists and architects are starting to find out through the architectural subfield known as biomimicry.

Biomimicry takes inspiration from observing biological processes and reconfiguring them into industrial design. A great example of this at work is in a new form of steel recently invented by researchers at NC State and the Chinese Academy of Sciences in Beijing. This improved steel can handle more stress and is far more ductile than normal steel because it possesses a similar cell structure to bamboo. Confused?

Here’s how it works:

Steel is made of tiny grains, which on normal steel are very densely packed together. Researchers found that by varying the size of the grains and the spacing between grains, they’re able to mimic bamboo’s bendable qualities, essentially making steel just as flexible.

In their study, they compared normal interstitial-free steel with this new “gradient structure” steel. Regular steel withheld 450-megapascals of stress before breaking and stretched only 5 percent, while gradient structure could withstand 500-mpa and stretched up to 20 percent.

To put it another way, if you took an 8×10 sheet of both types and stretched them lengthwise, gradient structure steel would stretch 19.2 inches, while regular steel would only stretch 4.8 inches. This exciting development means a new material that’s not only safer, but also more versatile in production terms and applications.

From commercial air conditioning systems modeled after a termite nest, to a window design that imitates honeycomb, it would seem that nature is slowly but surely beginning to influence our architecture rather than the other way around.

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