Mechanical metamaterial

Mechanical metamaterials are artificial materials with mechanical properties that are defined by their mesostructure in addition to than their composition. They can be seen as a counterpart to the rather well-known family of optical metamaterials. They are often also termed ''elastodynamic metamaterials'' and include acoustic metamaterials as a special case of vanishing shear. Their mechanical properties can be designed to have values which cannot be found in nature. Provided by Wikipedia