Mechanical Properties Of Carbon Networks From Impact Of Fullerenes On Few-Layered Graphene

In the past decade,graphene and its derivative structures have attracted the attention of researchers in various scientific fields due to their unique properties.Due to its low cost and mass production,multi-layer graphene is more suitable for practical application than single-layer graphene.However,the weak physical link between the layers results in a weak structure of this type of graphene.When a few-layered graphene ribbon acts as a component of a dynamics nanodevice,the ribbon has very low bending stiffness due to relative sliding between neighbor layers.To overcome the drawback,molecular dynamics simulations were used to study the formation of carbon networks with the cross-linking between layers of graphene sheets via the impact of high speed fullerenes(C₆₀).Further,the uniaxial tensile tests were carried out to reveal the mechanical properties of the welded graphene sheets.The main results in this paper are as follows:First,in order to form a cross-linked carbon network structure in the few-layered graphene ribbon at room temperature,the high-speed fullerenes were used to impact the graphene ribbon from both sides of the ribbon.The feasibility of the proposed method has been verified by experiments and molecular dynamics simulations.The molecular dynamics simulation method was used to study the impact effect considering the factors such as the number of bands（1-4 layers）and the injection rate of fullerenes.The linear search method was used to obtain the incident velocity ranges of C₆₀ fullerenes to the one-to-four layers.The velocity intervals are[115,135]?/ps,[130,165]?/ps,[140,200]?/ps,and[160,260]?/ps,respectively.Due to the adjacent layers support,the upper and lower limits of the interval increase with the increase of the number of layers in the same plane size in the band during the collision.When fullerenes collide synchronously with the graphene surface at the same speed,the new carbon networks formed in the two collision regions are different due to the asymmetric collision effect caused by the thermal vibration of the atoms on the graphene.Therefore,it is difficult to generate symmetrical carbon networks by shot peening in practical experiments.In the collision region,the adjacent graphene layers can be connected by a newly formed carbon network which prevent the interlayer relative sliding.After collision,the few-layered graphene ribbon was connected by the newly formed carbon networks at the collision regions.To evaluate the in-plane mechanical properties of the new carbon material,the uniaxial tensile tests were fulfilled considering the effects of temperature,strain rate and tensile direction.By comparing with the mechanical properties of the pristine graphene ribbon,it was found that the maximum engineering strain of the carbon network is slightly related to the loading speed and temperature,and is about 53%lower than that of the pristine ribbon.The Young’s modulus reduces about 13%,but the elastic strain range becomes higher.The tangent modulus of the new carbon network decreases with increasing temperature.The results of this study proposed a new graphene structure.It has no interlayer relative sliding,which is significant for the dynamics response of a nanodevice based on the new structure.