Buckling analysis of carbon nanotubes and the influence of defect position

In this paper, the buckling behavior of fixed-fixed, both single- and multi- wall carbon nanotubes (CNTs) under axial compressive loads, are studied using analytical continuum theory and molecular dynamics (MD). An approach based on the tethering of atoms, is used to apply the boundary conditions and extract the reaction forces during the MD simulation. Both the analytical and the MD results agree well for slender CNTs (length=diameter = L/D ≥ 9), that show global buckling. The critical buckling load of non slender CNTs (L/D < 9) is overestimated by the analytical model due to the local buckling. Moreover, the effects of the vacancy defect position on the critical buckling load are studied at room temperature and at low temperature (1 K). It is concluded that the defects at the ends of the CNT and close to the middle of the CNT significantly reduce the critical buckling load and strain of CNTs at 1 K. However, the influence of vacancy defects on the critical buckling load and strain appears to be small at room temperature. The MD results can be used for developing more computationally efficient and accurate continuum descriptions of the CNT mechanics in future work.