Taking their cues from nature, a team of researchers from London created a material that can be squeezed repeatedly without damage and still hold energy.
The last place small rodents or birds want to be is in the grip of a bird of prey like an eagle. Eagles are equipped with feet that allow them to store energy without needing to contract their muscles.
Materials based on eagles' grips
Once an eagle has its grip around prey, that prey doesn't stand much chance. Scientists at Queen Mary University of London and the University of Cambridge took these features of an eagle and used it to create their material.
This style of material is called auxetics, and they typically behave differently from other materials. They often collapse in directions and store the energy inside.
Most auxetic material designs have sharp edges and corners, however, that allow them to have a higher density. The new material from the British researchers is shaped with smooth curves.
This distributes the force and makes repeated deformations whenever a material needs to change shapes. This material could be used in everything from 3D supports to robotics shells to help absorb energy impact.
"The exciting future of new materials designs is that they can start replacing devices and robots," principal investigator Dr. Stoyan Smoukov, from Queen Mary University of London, said. "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."
Looking further into nature for more inspiration
Nature frequently inspires roboticists and engineers, and this international team of researchers plans on looking to nature's equipment to inspire more of their own. In a statement, they noted the design could be used as an energy-efficient tool in industries or even create lattices with unique responses to heat or cold.
Eesha Khare, a visiting undergraduate student from Harvard University who was instrumental in defining the project, added: "A major problem for materials exposed to harsh conditions, such as high temperature, is their expansion. A material could now be designed so its expansion properties continuously vary to match a gradient of temperature farther and closer to a heat source. This way, it will be able to adjust itself naturally to repeated and severe changes."
Smoukov and the team ensured the material was capable of being 3D printed, making them relatively lower cost and easily replicated. "By growing things layer-by-layer from the bottom up, the possible material structures are mostly limited by imagination, and we can easily take advantage of inspirations we get from nature," Smoukov added.
The study was published in Frontiers journal.