Anisotropic mechanical properties of graphene sheets from molecular dynamics

• Published in: Physica. B, Condensed matter Condensed matter, 2010-03, Vol.405 (5), p.1301-1306
• Main Authors: Ni, Zhonghua, Bu, Hao, Zou, Min, Yi, Hong, Bi, Kedong, Chen, Yunfei
• Format: Article
• Language: English
• Subjects: Anisotropic mechanical property; Anisotropy; Condensed matter; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Fracture; Graphene; Mechanical and acoustical properties of condensed matter; Mechanical properties; Mechanical properties of nanoscale materials; Modulus of elasticity; Molecular dynamics; Molecular structure; Physics; Stress-strain relationships; Unit cell; Young's modulus
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2009.11.071

Anisotropic mechanical properties are observed for a sheet of graphene along different load directions. The anisotropic mechanical properties are attributed to the hexagonal structure of the unit cells of the graphene. Under the same tensile loads, the edge bonds bear larger load in the longitudinal mode (LM) than in the transverse mode (TM), which causes fracture sooner in LM than in TM. The Young's modulus and the third order elastic modulus for the LM are slightly larger than that for the TM. Simulation also demonstrates that, for both LM and TM, the loading and unloading stress–strain response curves overlap as long as the graphene is unloaded before the fracture point. This confirms that graphene sustains complete elastic and reversible deformation in the elongation process.