A DFT-based finite element approach for studying elastic properties, buckling and vibration of the arsenene

Vibrational analysis of double-walled silicon carbide nano-cones: a finite element investigation

A three-dimensional finite element model is used to investigate the vibrational properties of double-walled silicon carbide nano-cones with various dimensions. The dependence of the vibrational properties of double-walled silicon carbide nano-cones on their length, apex angles and boundary conditions are evaluated. Current model consists a combination of beam and spring elements that simulates the interatomic interactions of bonding and nonbonding. The Lennard-Jones potential is employed to model the interactions between two non-bonding atoms. The fundamental frequency and mode shape of the double-walled silicon carbide nano-cones are calculated.

On the derivation of coefficient of Morse potential function for the silicene: a DFT investigation

In this paper, the structural and mechanical properties of silicene are investigated by the density functional theory calculations. To calculate Young's, bulk, and shear moduli and Poisson's ratio of the silicene, the optimized unit cells containing two atoms are proposed and the effect of chirality on the elastic properties of silicene is examined. It is shown that the silicene has an isotropic behavior, while graphene has an anisotropic behavior. The results showed that calculated moduli for the silicene are significantly lower than those of graphene in zigzag and armchair directions, while Poisson's ratio of silicene is higher than that of graphene. The paper describes one common type of inharmonic interatomic potentials used for constructing nonlinear models of the material using the modified Morse potential function. Using this concept, the effects of chirality on dissociation energy, inflection point, and coefficients of the modified Morse potential function are studied. Comparison of the cutoff distance value in the modified Morse potential showed that inflection point values for the armchair and zigzag graphene are highly direction-dependent, whereas these values have negligible difference for silicene.

Torsional buckling analysis of MWCNTs considering quantum effects of fine scaling based on DFT and molecular mechanics method

In this paper, quantum and molecular mechanics are used to study the quantum effects of fine scaling on the buckling strength of multi-walled carbon nanotubes (MWCNTs), as well as the effects of changes in length, diameter, chirality, wall number and length-to-diameter ratio of the structure under torsional loading. To this end, the total potential energy of the system is calculated with the consideration of both bond stretching and bond angular variations. The density functional theory (DFT) along with the generalized gradient approximation (GGA) function is used to obtain the relevant elastic constants of the nanotubes. The study shows that the quantum effects of fine scaling cause more buckling strength of the structure against external torsional loadings. Also, with any longitudinal change as well as the changes in the structural arrangement that reduce the quantum effects of fine scaling, the strength of the structure decreases sharply.

Structural and mechanical properties of antimonene monolayers doped with transition metals: a DFT-based study

In the current study, the elastic and plastic properties of the 2 × 2 and 3 × 3 pristine and transition metal (TM)-doped antimonene are studied through DFT calculations. Sc, Ti, V, Cr, Fe, Co, Ni, Cu, and Zn atoms are selected as the doping atoms. It was observed that Young's and bulk moduli of both 2 × 2 and 3 × 3 pristine structure would decrease while affected by the doping atoms. The highest reduction in the Young's and bulk moduli of the 2 × 2 nanosheets has occurred in the Cr- and Ti-doped structures, respectively, while the same reduction was observed in the V- and Ti-doped structures in the 3 × 3 nanosheets. In addition, it was shown that all of the investigated structures express isotropic behavior since the obtained Young's moduli of these nanostructures have negligible difference along armchair and zigzag directions. Finally, the loading is further increased to investigate the plastic behavior of these structures. The results showed that except for 2 × 2 Sc-doped structure under biaxial loading, the yield strain of all doped nanosheets would decrease under uniaxial and biaxial loadings. The highest reduction in the yield strain of the 2 × 2 nanosheets under biaxial loading has been observed in Cu-doped nanosheet while in 3 × 3 nanosheets, the highest reduction has occurred in Cu-, Fe-, and Zn-doped nanosheets under the same condition. As for the yield strain of the doped 2 × 2 nanosheets while affected by the uniaxial loading, Cu- and Zn-doped nanosheets experienced the highest reduction while in 3 × 3 nanosheets, the highest reduction has been observed for Cr-doped nanosheet under the same condition.