  Atomistic simulation was performed to study the mechanical properties of few
layer graphene (FLG) in conjunction with monlayer graphene (MLG) under uniaxial
elongation by systematically increasing the layer number from one to six. We
found that the ultimate tensile strength and strain increased in these FLGs for
both zigzag and armchair-directional elongations when compared with the results
of MLG. We also found that the largest increments were obtained in bi- or
tri-layer graphene for all the FLG systems we studied. Using atomic stress
distribution analysis, it is observed that the width of the distribution became
narrower, thus the maximum stress decreased in FLG compared to MLG at
respective stages of identical tensile stress. It indicates that locally-driven
highly elevated atomic stress of FLG has been effectively relaxed to the atoms
in other layers through cooperative interlayer interaction. This effect
explains the reason for synergetic mechanical strengthening of FLG since
tensile failure is critically influenced by maximum atomic stress. Furthermore,
the Young's moduli were slightly smaller for all FLGs compared to MLG.
