Investigation of the vibration and buckling of graphynes: A molecular dynamics-based finite element model

摘要

Molecular dynamics simulations are used to investigate the mechanical properties of graphynes. To study the effect of atomic structure and graphyne size on Young's and bulk modulus, armchair and zigzag nanosheets with different side lengths and aspect ratios are considered. It is observed that at a constant aspect ratio (the ratio of height to side length), variation of side length has no significant effect on Young's modulus of graphynes. Besides, using the obtained results by molecular dynamics simulations, a finite element model is proposed to study the vibrational and buckling behaviors of graphynes. The effects of different parameters such as nanosheet geometry and boundary conditions on the fundamental natural frequency and critical buckling force of graphynes are explored. It is shown that increasing side length has an inverse effect on the frequency and buckling force. Increasing aspect ratio results in decreasing the frequency. However, this effect reduces for longer sheets. Increasing aspect ratio results in converging the vibration curves associated with graphynes under different boundary conditions. Moreover, by increasing aspect ratio, the sensitivity of buckling force to aspect ratio variation decreases.