Influence of atomic defects on the mechanical properties of carbon nanotubes

According to experimental observations, there are different types of atomic defects appearing in real samples of carbon nanotubes. This signifies the necessity to investigate the influence of these atomic defects, for example, on the mechanical properties of carbon nanotubes. Thus, this chapter compares the mechanical properties, i.e., Young's modulus, shear modulus and critical buckling load, of single- and multi-walled carbon nanotubes (armchair and zigzag tubes) in their perfect form and for three types of defective forms (different amounts of randomly distributed silicon impurities, vacant sites and structural perturbation in the space). The results reveal that the decreasing trends in the mechanical stiffness and stability of carbon nanotubes as a result of the defects follow either straight lines or parabolas whose relations are presented. It is also concluded that carbon nanotubes must be considered as anisotropic materials