Mechanical 'metamaterials' with peculiar properties

Materials with surprising, engineered properties are a hot talking point at a major US physics conference.

So-called "metamaterials" are fairly well-known, in the case of structures that are tweaked to manipulate things like their appearance - but the next phase is to change their mechanics.

One example is a slab of rubber, punched with carefully calculated holes, which can be 'programmed' to contract in two different directions, controlling its stiffness.

Another is an intricate, tiny lattice of hollow ceramic tubes that - when built from tubes with the correct wall thickness - is elastic instead of brittle.

These ideas could help build impact-sensitive bumper bars or robust tiles for spacecraft.

Videos courtesy of Bastiaan Florijn, Leiden University and Lucas Meza, California Institute of Technology.