Why the seahorse's tail is square

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Why the seahorse's tail is square

http://phys.org/news/2015-07-seahorse-tail-square.html

Why is the seahorse's tail square? An international team of researchers has found the answer and it could lead to building better robots and medical devices. In a nutshell, a tail made of square, overlapping segments makes for better armor than a cylindrical tail. It's also better at gripping and grasping. Researchers describe their findings in the July 3 issue of Science.



"Almost all animal tails have circular or oval cross-sections—but not the seahorse's. We wondered why," said Michael Porter, an assistant professor in mechanical engineering at Clemson University and the lead investigator on the study, who earned his Ph.D. in materials science and engineering at the University of California, San Diego, in 2014. "We found that the squared-shaped tails are better when both grasping and armor are needed."

Also remarkable, the square plates make the seahorse's tail stiffer, stronger and more resistant to strain at the same time. Usually, strengthening any one of these characteristics will weaken at least one of the others, Porter said. He and colleagues set out to find out why.

They found that square plates move with only one degree of freedom when crushed: they slide. By contrast, circular plates have two degrees of freedom: they slide and they rotate. As a result, the square plates absorb much more energy before permanent failure begins.

To arrive at their findings, researchers used a wide range of techniques, including 3D-printing a simplified model of the seahorse's tail, which they then bent, twisted, compressed and crushed. They also 3D-printed and ran similar experiments on a tail model made of overlapping round segments that they designed and that is not found in nature.

"New technologies, like 3D-printing, allow us to mimic biological designs, but also build hypothetical models of designs not found in nature," said Porter "We can then test them against each other to find inspiration for new engineering applications and also explain why biological systems may have evolved."


Read more at: http://phys.org/news/2015-07-seahors...quare.html#jCp