Evaluating the influence of defects on the young's modulus of carbon nanotubes using stochastic modeling

Abstract

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.

Keywords

• carbon nanotube
• defect
• finite element modeling
• young's modulus
• stochastic analysis