Investigation of strain rate effects on the mechanical behavior of polymer nanocomposites with and without defects in nanotubes

This paper examines the mechanical behavior of carbon nanotube (CNT)/epoxy nanocomposites with and without vacancy defects in the nanotube under uniaxial tension at different loading rates using molecular dynamics (MD) simulation. In order to validate the simulation process, first CNTs and polymer matrix were modeled separately with their behavior and performance investigated, showing the proper agreement of the physical and mechanical properties of the developed models with available studies. In the research process, a method was proposed for controlling the strain rate during loading using Souza-Martinez barostat to control the deformation uniformly. The results revealed that increasing the strain rate (at high rates) had little effect on the mechanical behavior of the isolated CNTs, while enhancing the mechanical properties of the pure polymer. The mechanical behavior of nanocomposite changed at different strain rates, and with elevation of the strain rate, the strength of nanocomposite decreased. Also, the presence of defects affected the form and sensitivity of the mechanical properties of the nanocomposite to the strain rate.