Deformation Of Carbon Nanotubes And Graphene Under Compressing Or Stretching Based On Molecular Dynamics

Carbon nanotubes (CNTs) are one dimensional quantum materials with specialstructure and graphene is a2-dimensional, crystaline allotrope of carbon. Both of them arecarbon nanomaterial and have a number of perfect mechanical, electrical and chemicalproperties. Molecular dynamics (MD) method takes advantage of modern computertechnology and the trajectories of atoms and molecules are determined by numericallysolving the Newton’s equations of motion for a system of interacting particles.Based on molecular dynamics, this work studies the effect of tube diameter on carbonnanotube under different temperature by using AIREBO. Then the vacancy defect whichcould weaken the mechanical property of CNTs is discussed. The result also reveals thatcoating with nickel atoms on the surface makes the critical stress and critical strain ofsingle-walled carbon nanotube (SWCNT) increase while the Young’s modulus decrease,which means nickel atoms enhance flexibility of CNTs. Poisson’s ratio of CNTs coatedwith nickel is lower than that of CNTs which means Van der Waals’ force between nickelatoms and carbon atoms prevent sectional area of CNTs from shrinking. After that, thiswork discusses the mechanical property of zigzag graphene under different temperature.Temperature has influence on the critical stress of graphene. Also, critical stress andYoung’s modulus of graphene coated with nickel atoms on both sides is much higher thanthose of graphene while critical strain change little. Temperature is the key factor ofmechanical properties of zigzag graphene coated with nickel atoms. Maximum tensionthat graphene and graphene coated with nickel atoms can bear would decrease because ofvacancy defect as well as the critical strain. Temperature will affect critical strain morethan vacancy defect do. However coating with nickel atoms would increase the maximumtension that graphene can bear.By simulating CNTs and zigzag graphene with molecular dynamics, it is found thatcoating with nickel atoms on the surface could enhance the mechanical properties but thevacancy defect would weaken the strength of them.