Atomistic Simulations on the Tensile Deformation Behaviors of Three‐Dimensional Graphene

Abstract

Molecular dynamics simulations is used to investigate the mechanical properties of three‐dimensional (3D) graphene under uniaxial tensile loading. The results show that the tensile deformation of 3D graphene exhibits size dependence along both armchair and zigzag directions. By analyzing the atomic von Mises stress and structural evolution, compared to the 3D graphene with smaller in‐plane cell size, the larger 3D graphene exhibits two typical deformation events, i.e., transverse structural shrinkage and axial elastic deformation. The fracture stress of 3D graphene is much smaller than that of 2D graphene because of its porous structure. However, the fracture strain of 3D graphene is larger than that of 2D graphene due to the larger transverse structural shrinkage along both armchair and zigzag directions. Effects of temperature, strain rate, and thickness of 3D graphene on the tensile behavior is investigated. The simulation results indicate that the fracture stress and the fracture strain decrease with increasing temperature and with decreasing strain rate. However, the fracture stress and the fracture strain is not dependent on the thickness of 3D graphene. The results in this paper suggest that 3D graphene with higher stretchability tunable by in‐plane cell size can be promising multifunctional materials for many engineering applications.

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“…But the comprehensive theoretical studies of CHs [9,[16][17][18][19][20][21][22][23] proved their superb strength and stability. This strength remains at a high level but tunable with different cell sizes [17,24] and crucially depends on defectness of CH structures [25]. The mechanical simulations [9] showed that the Young's modulus of the structures is de-termined solely by the density of the hinges, and deformations are localized, similar to that of macroscopic honeycombs.…”