Metamaterials are man-made materials that get their properties from the way the material is constructed rather than the material that constructs it. This allows researchers to manipulate a metamaterial's structure in order to make the material exhibit a certain property.
According to the researchers, since these properties are ‘topologically protected’, meaning that the material's properties come from its total structure, they're easily maintained even as the material shifts repeatedly between its hard and soft states.
Xiaoming Mao, assistant professor of physics at the University of Michigan, said the way an object comes in contact with the edge of the metamaterial changes the geometry of the material's structure, and therefore how the material responds to stress at the edge. But the metamaterial's topological protection allows the inside of the metamaterial to remain damage free.
The material could one day be used to help absorb impacts from a crash in cars.
“When you're driving a car, you want the car to be stiff and to support a load,” Mao said. “During a collision, you want components to become softer to absorb the energy from the collision and protect the passenger in the car.”
The researchers also suggest the material could be used to make bicycle tires that could self-adjust to ride more easily on soft surfaces such as sand, or to make damage-resistant, reusable rockets and rocket launch systems.