Friday, 25 May 2012

New metamaterial has negative compressibility

A system to demonstrate who the ends can be stretched while the subsystem compresses
Firstly, let me define a term:

Metamaterial: Metamaterials are artificial materials engineered to have properties that may not be found in nature.


Zachary Nicolaou and Adilson Motter of Northwestern University in Evanston, Illinois, have now designed a metamaterial that stretches when compressed, and vice versa, under any circumstances.

Trying to imagine such a material may induce a headache. For that purpose, this picture might help.

Any material that behaves this way (stretching when compressed, and vice versa) would be inherently unstable and instantly collapse into a stable state without displaying such behaviour. Nicolaou and Motter got around this by designing a material with an internal structure that does transition to a stable state, but a state that is more compressed or expanded than the original state.
"What is interesting is that they study systems that are not responding to a vibration but to a steady applied force," says John Pendry of Imperial College London.

Such a material, with unusual properties can be used to protect coatings of military vehicles, among other uses.
"If a blast hit the side of your vehicle, it would push back and try to cancel out some of the effect."

Further reading

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