New Metamaterial Can Switch From Hard To Soft And Back Again
There is good news about a new metamaterial that has been designed to act as both hard and soft material depending on the situation and still retain its original structure without any damage.
That means a car made of that metamaterial can still remain safe even after a collision with another vehicle because the components can absorb the energy of the crash by acting soft at once.
The feat of the team, led by Zeb Rocklin of the University of Michigan in the U.S., has been revealed in the paper published in Nature Communications.
The metamaterial developed by the team can be manipulated to increase both stiffness and softness to the extremes say, between rubber and steel.
Such fluctuating properties are backed by the total structure, which is well maintained even as the material transits repeatedly from hard and soft states.
"The novel aspect of this metamaterial is that its surface can change between hard and soft," explained Xiaoming Mao, assistant professor of physics and a co-author.
He said changing the stiffness of a traditional material is difficult because it will remain either hard or soft once the material has been made.
The fascinating properties of metamaterials come from the way they are constructed and not from any special property of the material from which it is composed. Properties such as hardness and softness are created by tweaking the structure of metamaterials.
In the study, the researchers used toy construction K'nex pieces in probing properties of a "topological transferable mechanical metamaterial" that when pressed against a hard object can increase its stiffness massively.
The material's scope for daily life applications is unlimited. It can be used in making cars. Many lives can also be saved in accidents with metamaterial absorbing the energy from the crashes and reducing the collision's intensity.
When the applications are extrapolated, the material can also find use in building rockets.
How Does It Work?
Explaining the functionality, Mao notes that while driving a car, the hope is that the car must be stiff and support a load.
But when there is a collision, the components need to be soft enough to absorb the energy from the collision and protect the passenger.
He said the material's hardness and softness come into play based on how the object makes contact with the edge of the metamaterial. As soon as the contact is made, a change in the material's geometry happens and it responds appropriately to the stress it bears at the edge.
This is despite the metamaterial remaining free from damage because of the innate topological protection.
Material Innovation On The Rise: Potential Of Cermet
Meanwhile, advancements in aerospace, automotive, and power generation have stepped up demand for innovative materials. Filling that demand is ceramic metal composites or cermets that enhance transportation and energy conversion technologies.
Cermets combine properties of their constituent materials in terms of high-temperature stability of ceramics and machinability of metals. But cermets become most effective when the constituent materials cease to react with each other during processing.
For that, Texas A&M University has come up with an efficient technology for processing ceramics and metals together into cermets without any reaction between constituent materials. The new technology has paved way for possibilities in developing superior composite materials.