Advances in mechanical analysis of structurally and atomically modified carbon nanotubes and degenerated nanostructures: A review

In the past few years, numerous research activities concerning the mechanical behavior of defected and imperfect carbon nanotubes have been conducted. It is reported that the superlative mechanical properties of these nano-structures, i.e. high stiffness, high strength and vibrational response, would be affected by existing or introducing defects and impurities in the structure of the nanotubes. Such defects may results from manufacturing routes or introduced on purpose to tailor certain physical properties. This review attempts to categorize and highlight the advanced breakthroughs and recent studies employed to investigate the mechanical properties, e.g. stiffness, buckling behavior and vibrational response of structural and atomically modified carbon nanotubes. The presented studies cover the mechanical behavior of nanotubes, both theoretically and experimentally which allowed a realistic prediction of the mechanical behavior of defected tubes in a closer form to those found in reality. It was concluded that any type of imperfection, either atomic or structural modification, influences the mechanical behavior of nanotubes and reduces the stiffness and structural stability, as well as vibrational response of these nano-structures. The present review includes: (i) a brief introduction to atomic and structural modification of nanotubes; (ii) a review of mechanical analysis of atomically and structurally modified models in two separate sections; and (iii) a detailed conclusion on the discussed studies and present the potential progress.