Mechanical metamaterials are materials that emulate mechanical properties through structuring at smaller size-scales.
The complement to mechanical metamaterials are the non-mechanical metamaterials. These include:
- Electromagnetic metamaterial with the subclasses of Optical metamaterials and crude Radio frequency metamaterials
- Thermal metamaterial
- Electrical metamaterials
Clear delineation to optical metamaterials:
The term "Metamaterial" without prefix is often used to refer to optical metamaterials. This may be because:
- Many existing mechanical metamaterials already have a name and are not consciously recognized as such (see below)
- More advanced mechanical metamaterials are maybe experimentally less accessible than optical metamaterials (questionable ...)
Known and existing cases of (passive) mechanical metamaterials are:
- many natural materials produced by living organisms (bones with structured voids, naca with layered protein and minerals, ...)
- .. there may be a few more that constitute whole different classes ??
Many unusual properties are (will be) possible.
For more examples see: Metamaterial#Examples
- Gemstone based metamaterial
- Topological mechanical metamaterial
- Going off-topic: Tensegrity
- Auxetics – one peculiar example of an nigh infinite amount of possibilities