Carbon nanotubes kirigami mechanical metamaterials.

Imparting elasticity and functionality to materials is one of the key objects of materials science research. Here, inspired by the art of kirigami, mechanical metamaterials comprising carbon nanotubes (CNTs) are hypothetically constructed. Using classical molecular dynamics (MD) simulations, a systematic study of the elastic limit, extensibility and yield stress of as-generated CNTs kirigami (CNT-k) is performed. Three designated kirigami patterns are employed to achieve high stretchability of CNTs. It is shown that CNT-k typically exhibits three distinct deformation stages, of which the first stage, which is referred to as geometric deformation, contributes quite a high proportion of the ductility. Various geometric parameters of CNT-k that influence the key mechanical properties of interest are respectively discussed. Three types of CNT-k with specifically identical geometric parameters exhibit distinct mechanical characteristics. This study provides an interesting example of interplay between the geometry, ductility, and mechanical characteristics of tubular materials.