The study attempts to explore the influences of the surface effect resulting in an initial relaxed unstrained deformation and the in-layer non-bonded van der Waals (vdW) atomistic interactions on the mechanical properties of single-walled carbon nanotubes (SWCNTs) using a proposed atomistic-continuum modeling (ACM) approach. The modeling approach incorporates atomistic modeling, by virtue of molecular dynamics (MD) simulation, for simulating the initial unstrained equilibrium state, and equivalent-continuum modeling (ECM), by way of finite element approximations (FEA), for modeling the subsequent static/ dynamic behaviors.
SWCNTs with various radius and two different chiralities, including zigzag and armchair type, are presented. To validate the proposed technique, the present results are compared with the literature data, including numerical and experimental values. Results show that the derived elastic moduli (1.2-1.4 TPa) when considering these two nanoeffects tend to be more consistent with the published experimental data. In specific, they can increase up to 17-23% Young's modulus, 5-15% shear modulus, 6-11% natural frequencies and 10-30% critical buckling load of the SWCNTs, implying that without considering these two effects, the material behaviors of SWCNTs would be potentially underestimated.