Study the effect of environment temperature on mechanical and fracture behavior of carbon nanotubes

The purpose of this paper is to deal with fracture behavior of carbon nanotubes with presenting a revised structural molecular mechanics model in the finite element method. Structural molecular mechanics modified model, uses a three-dimensional beam element with general section to make nanotube structural model in which bending stiffness and inversion are defined independently. In analysis which are done, a bridged carbon nanotube with constant strain rate is examined under tensile stress until the failure of nanotube. Carbon-carbon bonds behavior has been assumed nonlinearly and will be ruptured when the strain reaches 19%. It is predicted that fracture behavior in carbon nanotubes depends on the environment temperature due to mechanical behavior of carbon nanotube's bonds. Based on the present research, we found that by increasing the temperature, Poisson's ratio increases and Young's modulus decreases. Further, it can be said while the temperature increases, both the fracture ultimate strain and stress decrease. Finally, a nonlinear relationship is presented in which the constants depend on chirality of the carbon nanotubes.