Prediction of Mechanical Properties of Coiled Carbon Nanotubes by Molecular Structural Mechanics Based Finite Element Modelling

Abstract

Carbon nanotubes (NTC) have very spectacular mechanical properties related to their nanometric structure, their perfect arrangement and their one-dimensional geometry. As with all materials, structural defects are inevitable and affects NTC properties. Among these defects, we distinguish the topological defects, the dislocations and the penta-hepta defect. But the presence of these defects is not totally harmful, because the existence of some structure like the coiled nanotube is the result of these defects. For this, in the first part of this work, the coiled carbon nanotube structure is studied, a method for the designing of this structure is proposed, the geometric parameters are detailed and the structural coefficients are determined. Therefore, a procedure for moving from a graphene sheet to a coiled nanotube is developed. Then, the second part of this study represents an attempt to calculate the spring constants of the spiral carbon nanotube. Mechanical properties of this material are investigated by means of molecular structural mechanics (MSM) method in ANSYS finite element code. The model serves as a link between the computational chemistry and the solid mechanics by substituting discrete molecular structures, with an equivalent-structural model. A coiled carbon nanotube has been modeled on the nanoscale by one-dimensional elements (3D beam). The results show a considerable influence of structural parameters (diameter, chirality, pitch and defect position) on the coiled nanotube mechanical properties.

Insight into Geometry-Controlled Mechanical Properties of Spiral Carbon-Based Nanostructures

“…They also showed that the stretchability of HCNT was in the range of 400–1000%. Some other researches have investigated the mechanical properties of different types of CCNTs. − Recently, Zhan et al ,, proposed GH as a new nanoscale spring. This structure is very similar to some types of CCNTs with an ellipsoidal cross-sectional structure.…”