Important parameters in molecular dynamic simulation of single wall carbon nanotubes with and without Stone-Wall defects during calculating mechanical properties

Carbon nanotubes have attracted special interest due to their extraordinary mechanical and electrical properties and with a wide range of applications, such asnanometer-scale devices and composite materials in the air-space and car industry. Recently investigation of single wall carbon nanotubes (SWCNT) with Stone-Wall defects is more interested because experimental researches often ends with some unwanted defectsproduced in them during their production, purificationor functionalization. Here we study SWCNT properties with and without Stone-Wall defect and theirmechanical properties have been calculated using molecular dynamic (MD) simulation. We have performed MD using the software LAMMPS. To makeStone-Wall defect two pentagons and two heptagons produced by the 900rotation of a C-C bonding the honeycomb structure of SWCNT. By changing the (z, r,θ) values, defects are created at different positions of the same tube. Two different SWCNTs are taken in this study, The zigzag, and armchair tubes. the first twolayers of atoms on both ends of a SWCNT were held rigid .The all atoms except the boundary ones rigidlyheld were treated as thermostat atoms. Tubes wasstretched in the z direction while other end fixed. Many parameters that effect calculating their mechanicalproperties observed including, inter-atomic potentials, thermostat atoms, relaxation steps, temperature, defects. We calculated the Young’s Modulus based on continuum mechanics theory.

Keywords:

single wall carbon nanotubes , molecular dynamic simulation , Stone-Wall defects