Molecular Dynamics Study of the Mechanical Behavior of Few Layer Graphene

TL;DR

This study uses atomistic simulations to analyze how the mechanical properties of few-layer graphene improve with increasing layers, revealing enhanced tensile strength and stress distribution effects compared to monolayer graphene.

Contribution

It provides new insights into the layer-dependent mechanical behavior of graphene, highlighting the synergistic strengthening effect in few-layer systems.

Findings

Tensile strength and strain increase with layer number.

Atomic stress distribution narrows, reducing maximum stress in FLG.

Young's modulus slightly decreases in FLG compared to MLG.

Abstract

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.