Predicting mechanical properties and compressive behavior of single-walled carbon nanotubes/graphene nanosheets connections using the finite element method

In this paper, the atomistic finite element model is used to study the compressive behavior and mechanical properties of singlewalled carbon nanotubes-graphene nanosheets junctions with different boundary conditions. Considering nanotubes as space frame structure, classical structural mechanics approaches can be used to study their mechanical behaviors. The beam and mass elements are used to model the bonds and atoms, respectively. In order to determine the properties of the beam elements, the energy tems in molecular mechanics are equated to those in the structural mechanics. The present analysis provides useful data about the applicability of finite element model to predict the elastic modulus and critical compressive forces of carbon nanotube-graphene junctions. The results show that in a constant aspect ratio (the ratio of the length to the radius of nanotubes), increasing length of the nanotube leads to decreasing the critical compressive force. While the elastic modulusis constant. Moreover, increasing aspect ratio results in decreasing the critical compressive force negligible increasing in elastic modulus. The amount of critical compressive force of the nanotubes under clamped-clamped boundary condition is more than the other boundary conditions. Finally, the first ten mode shapes of the armchair and zigzag nanotubes are drawn for one-side and two-sided junctions, and it is shown that the mode shapes of the armchair and zigzag nanotubes are almost similar.