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Eagle talon-inspired 'auxetic' material could create energy-efficient devices


A Bald Eagle with its catch (Credit: Shutterstock)
A Bald Eagle with its catch (Credit: Shutterstock)

A new material inspired by an eagle’s firm grip after catching prey could help create energy-efficient tools or reconfigurable devices, its creators have said.

The research team, from Queen Mary, University of London and the University of Cambridge, were inspired by eagles’ ability to store energy in their talons without having to continuously contract their muscles.

Instead of bulging when squeezed, the material design created by the researchers is shaped in such a way that it collapses in all directions, storing the energy within.

Previous examples of that material design, called auxetics, had sharp corners that folded in to become denser. This design fractured after several compressions, the team said, so they redesigned auxetic materials with smooth curves to evenly distribute forces and make repeated deformations possible for applications where energy storage and shape-changing are needed.

The work could lead to lightweight 3D supports that fold in specific ways and store energy to be released on demand.

“The exciting future of new materials designs is that they can start replacing devices and robots,” said principal investigator Dr Stoyan Smoukov from Queen Mary.

“All the smart functionality is embedded in the material, for example the repeated ability to latch onto objects the way eagles latch onto prey, and keep a vice-like grip without spending any more force or effort.”

The team expects that developers could use the designs in energy-efficient gripping tools for industry, reconfigurable shape-changing materials, and even lattices with unique thermal expansion behaviour.

The researchers specifically designed the materials to be 3D-printed. “By growing things layer-by-layer from the bottom up, the possible material structures are mostly limited by imagination,” said Smoukov. “We can easily take advantage of inspirations we get from nature."

The study was published in "Frontiers in Materials".

Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.

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