Mechanical properties of single-walled carbon nanotubes: a comprehensive molecular dynamics study

There is inconsistent information across the literature related to tensile and compressive mechanical properties of carbon nanotubes (CNTs). This inconsistency arises from different sources such as the technical difficulties associated with testing and measuring the CNTs mechanical properties in the laboratory or the use of different input parameters (e.g. CNT wall thickness or boundary conditions) in numerical simulations. To address this inconsistency, an extensive series of molecular dynamics (MD) simulations is carried out in this study to investigate the influences of major factors including chirality, size, aspect ratio and slenderness ratio of CNTs on their mechanical properties, which have not been examined as extensively in previous studies. Numerical simulations are repeated for different temperatures of 100 K, 300 K and 500 K to investigate the influence of temperature in different practical applications. The agreements between the findings of this study and those from related previous studies are discussed in detail in the paper. Results on compressive behavior show the emergence of secondary and tertiary buckling modes as the slenderness ratio of the CNT increases, especially at higher temperatures. In addition, chiral CNTs are found to buckle at lower stresses and strains. Results on tensile behavior indicate a nonlinear-elastic response for all CNTs examined. Larger-diameter CNTs are found to fail at lower values of tensile stress and strain. (paper)