Molecular dynamics simulation of defected carbon nanotubes

摘要

The influence of vacancy defects on the Young's modulus of carbon nanotubes (CNTs) is studied. Firstly, the Young's moduli of nondefected CNTs are predicted using two different nonlinear force fields. The stress-strain curves of CNTs are obtained up to the failure points and corresponding Young's modulus and failure strain are reported. Then, the influence of CNTs diameter, chirality, and length on the results is extensively analyzed. Secondly, the influence of vacancy defects on the Young's modulus of CNT is evaluated using molecular dynamics simulation. Both numbers and locations of defects are treated as random parameters. Therefore, stochastic modeling procedure is employed. The Young's modulus of defected CNTs are obtained and compared with nondefected ones. The obtained results are compared with available date in literature. It is revealed that nanoscale continuum modeling which is used as a compromise in modeling of nanostructure underestimates the reduction level in the Young's modulus of defected CNTs. A linear reduction trend is observed for the Young's modulus of defected CNTs with respect to the number of vacancy defects. Moreover, the locations of defects play an important role in defining the degree to which the Young's modulus decreases.