Research on the auxetic behavior and mechanical properties of periodically rotating graphene nanostructures

Abstract

Negative Poisson’s ratio (auxetic) material is one of the most widely studied metamaterials, and recent attempts have been made to discover auxeticity in graphene-based and related carbon-based materials. However, it is shown that negative Poisson’s ratio effect requires special conditions, such as high temperature. Achieving negative Poisson’s ratio effect under large strain at ambient conditions is the key to graphene materials in nano-device applications. In order to discover the auxetic properties of nanostructures under large strain, this article proposes periodically rotating graphene nanostructures (PRGNs) which are the combination of graphene and rotating rigid unit structures. Poisson’s ratio, Young’s modulus, and damage mechanism of PRGNs are investigated using molecular dynamics simulation. It can be possible to conclude that PRGNs can also exhibit auxetic behavior, and their negative Poisson’s ratio effect can be maintained even at large strains (ε ∼ 0.1). Poisson’s ratio can be regulated by adjusting the value of the geometry parameters of the graphene sheets (GSs), which comprise the PRGNs, and changed from negative to positive and from positive to negative. Also, the influences of the structural size of GSs and the connection angle between GSs on the mechanical properties are explored, which will provide a theoretical basis for the preparation and performance optimization of GSs and the nano-auxetic properties of materials.

Keywords

• graphene
• auxetic properties
• molecular dynamics
• poisson’s ratio
• mechanical properties