Atomistic understanding of the anisotropic tensile response and zero-stiffness of carbon honeycomb nanostructure

ABSTRACT

Carbon honeycomb (CHC) is a novel carbon allotrope with excellent mechanical and physical properties and has great potentials for various energy and environmental applications. In this work, the tensile response of the CHC nanostructure is re-examined via molecular dynamics simulation to provide an atomistic understanding of its anisotropic mechanical properties and zero-stiffness as reported previously. The simulation results obtained demonstrate that the tensile response of CHC is closely related to the deformation of its constitutive graphene nanoribbons. To illustrate the underlying deformation mechanisms of the nanoribbons, the evolution of their atomic structure during the deformation is characterised by calculating several characteristic bond lengths and angles, and the atomic stress distribution. It is found that when tensile loading is applied in the armchair direction, the graphene nanoribbons undergo severe distortion and subsequent distortion flattening as the tensile strain increases, which leads to the zero-stiffness behaviour. For the tensile loading applied in the zigzag direction, the graphene nanoribbons are mainly stretched without distortion, giving rise to the anisotropic tensile response of CHC. In addition to the zero-stiffness and anisotropic behaviour, the negative Poisson’s effect is also observed when a tensile loading is applied in the armchair direction.

KEYWORDS:

• Carbon honeycomb
• tensile response
• molecular dynamics simulation

Acknowledgements

The authors would like to acknowledge the financial support from the National Natural Science Foundation of China (No.11802087) and the high-performance computing resource from the National Supercomputing Center in Changsha.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 11802087].