Effects Of Scale And Van Der Waals Force On Critical Buckling Of Multiwall Carbon Nanotubes

This paper studies the effect of small scale and precise van der Waals force on multiwall carbon nanotubes on the basis of the existing researches and non-local continuum medium mechanics column shell model. As most of the former researches didn't take this effect into account, so this paper gives an in-depth comparison to the former ones.This paper is based on the non-local elastic theory under the effect of small scale. The model assumes that multiwall carbon nanotubes are composed of non-local elastic column shell with equivalent elasticity quantity, thickness, and get the domination equation of the multiwall carbon nanotubes under different combined loads and small scale effect. The van der Waals force is expressed in L-J model and will take in to the effect of all the layers of the tube. The force between the tube and body is in Whitney-Riley elastic model. In the real examples, this paper studied the effect of the small scale effect on the torsional buckling, press combined buckling and inner pressure condition.In addition, a thin N-wall nanotubes (defined by the inner radius-to-thickness ratio larger than 5) is shown to be approximately equivalent to a single layer elastic shell whose effective bending stiffness and thickness are N times the effective bending stiffness and thickness of singlewall carbon nanotubes. Based on this result, an approximate method is suggested to substitute a multiwall nanotube of many layers by a multiplayer elastic shell of fewer layers with acceptable relative errors.Finally, this paper gives out the domination equation of the multiwall carbon nanotubes under precise van der Waals force and studied the effect of the precise van der Waals force on multiwall carbon nanotubes.The results of this paper are useful for the devices that use multiwall carbon nanotubes as basic components.