Asymmetric chiral and antichiral mechanical metamaterials with tunable Poisson’s ratio

Geared Topological Metamaterials with Tunable Mechanical Stability

The classification of materials into insulators and conductors has been shaken up by the discovery of topological insulators that conduct robustly at the edge but not in the bulk. In mechanics, designating a material as insulating or conducting amounts to asking if it is rigid or floppy. Although mechanical structures that display topological floppy modes have been proposed, they are all vulner...

Terahertz chiral metamaterials with giant and dynamically tunable optical activity

Jiangfeng Zhou,1,* Dibakar Roy Chowdhury,1 Rongkuo Zhao,2 Abul K. Azad,1 Hou-Tong Chen,1,† Costas M. Soukoulis,2 Antoinette J. Taylor,1 and John F. O’Hara1,‡ 1Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA 2Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, ...

Lightweight Mechanical Metamaterials with Tunable Negative Thermal Expansion.

Ice floating on water is a great manifestation of negative thermal expansion (NTE) in nature. The limited examples of natural materials possessing NTE have stimulated research on engineered structures. Previous studies on NTE structures were mostly focused on theoretical design with limited experimental demonstration in two-dimensional planar geometries. In this work, aided with multimaterial p...

Metamaterials with Tunable Nonlinearity

Chiral three-dimensional lattices with tunable Poisson’s ratio

Chiral three-dimensional cubic lattices are developed with rigid cubical nodules and analyzed via finite element analysis. The lattices exhibit geometry dependent Poisson’s ratio that can be tuned to negative values. Poisson’s ratio tends to zero as the cubes become further apart. The lattices exhibit stretch-twist coupling. Such coupling cannot occur in a classical elastic continuum but it can...