1,720,974 research outputs found
Buckling and post-buckling analysis of single wall carbon nanotubes using molecular mechanics
No full textThis paper deals with a numerical model for the buckling and post-buckling analysis of single-wall carbon nanotubes. Reasons of efficiency lead to the choice of a simple molecular statics model, wherein binary, ternary and quaternary atomic interactions are accounted for and described using Morse and cosine potential functions. The equations of the model are discussed in depth and the parameters of the potential functions are justified in the light of a comparison with ab-initio results. Several case studies regarding zigzag and armchair tubes of different aspect ratios, under compression, bending and torsion, are addressed with the aim of investigating the efficacy of the model and the role of the quaternary interactions, in contexts of both global and local behaviours
In-plane and out-of-plane tensile behaviour of single-layer graphene sheets: a new interatomic potential
No full textThis paper compares simple interatomic potentials for carbon nanostructures with hexagonal lattice, by investigating the in-plane and the out-of-plane tensile behaviour of single-layer graphene sheets. Attention is given both to potentials already considered in the literature and to a new one, which we call the damped DREIDING potential, in which damping functions are added to the DREIDING potential. For each potential, a calibration of its parameters and a focus on its performance are carried out in the in-plane context, by comparison with ab initio results of the rigidities and of the tensile limit properties, under periodic conditions. In addition, the damped DREIDING potential is used to perform in-plane tensile tests on both pristine and perforated single-layer graphene sheets of finite size. In the out-of-plane context, the calibration from ab initio results is only possible with reference to the rigidity. For the damped DREIDING potential, a sensitivity analysis, applied to a nanoindentation problem, on a pristine single-layer graphene sheet of finite size is provided. In doing so, a narrow range of value of the force needed to remove an atom from a sheet is given
On the derivation of the elastic properties of lattice nanostructure: The case of graphene sheets
No full textSeveral nanomechanics approaches based on common two or three-body potentials are compared. Numerical simulations and analytical approaches are used to investigate the not negligible differences among the prediction of the in-plane elastic constants of graphene sheets in the literature, exploring separately the role of the bonding potentials and that of the structural descriptions (beams and trusses) of the original Molecular Mechanics (MM) model. The energetic differences between structural models and MM models will be highlighted through exact discrete homogenization procedure. By the way, some theoretical expression of graphene elastic constants available in the literature are recovered and supported by numerical experimentation. The results provide also an assessment of the accuracy of the selected potentials with repost to both ab-initio reference solutions and the experimental measurements available. Some suggestions towards a reparametrization of the modified Morse potential are consequently formulated
Experimental evaluation of different suspension systems for agricultural vehicles through four-poster test bench
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A computational approach for the hygro-thermal modeling of wood under surface densification
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