Anisotropic Thermal and Mechanical Characteristics of Graphene: A Molecular Dynamics Study

In the present work, molecular dynamics simulation has been performed to characterize the thermal and mechanical behavior of graphene sheet. For this purpose, graphene sheet is subjected to dynamic heating process and its melting point has been predicted. Structural and thermal properties have been analyzed using radial distribution function and energy per atom. To analyze factors affecting melting temperature, four graphene sheets with different dimensions have been chosen for the dynamic heating process. The melting temperature of graphene decreases with increase in the sheet dimension, hence graphene sheet having smaller dimensions show relatively better thermal stability. To analyze the mechanical behavior, graphene sheet has been subjected to uniaxial tensile loading along zigzag and armchair directions respectively. It is observed that zigzag-oriented graphene sheet shows high fracture strength and stability as compared to armchair direction. Multilayer graphene sheets have been selected to investigate the effect of multilayers on the mechanical strength. It can be revealed from results that fracture strength decreases with increase in layers, however, brittleness of the sample relatively decreases with increase in a number of graphene layers.