Predicting a stretching behavior of carbon nanotubes using finite element method

Abstract

This paper describes a finite element method that is appropriate for the numerical prediction of the nonlinear mechanical behavior of different types of isolated single walled carbon nanotubes. A finite element progressive fracture model based on the modified Morse interatomic potential is used to evaluate mechanical properties of carbon nanotubes, such as axial and radial Young's modulus, shear modulus, natural frequency and buckling load are presented to illustrate the accuracy of this simulation technique. The novelty of the model lies on the use of beam element with non-linear capability, i.e, BEAM188, to evaluate SWNTs mechanical properties. In the present modeling work, individual carbon nanotube is simulated as a frame-like structure and the primary bonds between two nearest-neighboring atoms are treated as 3D beam elements. The beam element nonlinear properties are determined via the concept of energy equivalence between molecular dynamics and structural mechanics using Modified Morse potential. The calculated mechanical properties show good agreement with existing other work and experimental results as shown in Table I.