Abstract The main goal of this research is to extract a suitable continuum modeling of buckyball-C60. For this purpose, firstly the lattice structure of buckyball-C60 is modelled and subsequently a spherical structure equivalent to fullerene structure is considered. The fullerene structure modeled with shell elements is under internal pressure and in the continuum shell modeling process. The results of simulation demonstrate that the fullerene structure can be modelled using spherical structure. The comparison between strain energies of the equivalent fullerene spherical model and molecular mechanics model under radial displacement, shows that C60-fullerene spherical structures can be modeled using a shell with 0.665 Å thickness, 5.07 TPa elastic modulus and 0.165 Poisson's ratio or a shell with 0.75 Å thickness, 4.84 TPa elastic modulus and 0.19 Poisson's ratio. Moreover, the applied elliptical strain is used to demonstrate that the performance of the continuum spherical shell model of C60 is faultless.

The main goal of this research is to investigate the influence of structural defects on the mechanical properties of single-walled carbon nanotubes (CNTs). Two different types of the structural defects called Stone-Wales and vacancy defect are studied. While the former is categorized under the process-induced defect and it appears during the growth process of CNT, the later is caused when chemical functionalization is applied to CNT for fabrication carbon nanotube reinforced nanocomposite providing better bonding between CNT and surrounding resin. The number of broken C-C bonds, distributions and their orientations are all taken into account as random variables accounting for full stochastic analysis. Therefore, a computer code is provided for the stochastic modeling. The finite element (FE) model of the CNT is built using nanoscale continuum mechanics approach and then structural defects are applied randomly to the CNT. The Young's modulus of defected CNTs are obtained and compared with non-defected ones. It is revealed that the importance of vacancy defect is considerably higher than that of Stone-Wales defects implying on the drawback of chemical functionalization process. A detailed study is carried out on the topology of the defect and also continuous probability density functions of defect CNT Young's modulus are characterized.