Evolution of the Carbon Nanotube Bundle Structure Under Biaxial and Shear Strains

Abstract

Close packed carbon nanotube bundles are materials with highly deformable elements, for which unusual deformation mechanisms are expected. Structural evolution of the zigzag carbon nanotube bundle subjected to biaxial lateral compression with the subsequent shear straining is studied under plane strain conditions using the chain model with a reduced number of degrees of freedom. Biaxial compression results in bending of carbon nanotubes walls and formation of the characteristic pattern, when nanotube cross-sections are inclined in the opposite directions alternatively in the parallel close-packed rows. Subsequent shearing up to a certain shear strain leads to an appearance of shear bands and vortex-like displacements. Stress components and potential energy as the functions of shear strain for different values of the biaxial volumetric strain are analyzed in detail. A new mechanism of carbon nanotube bundle shear deformation through cooperative, vortex-like displacements of nanotube cross sections is reported.

The Fingerprints of Resonant Frequency for Atomic Vacancy Defect Identification in Graphene

“…In addition, the fingerprints of resonant frequencies provide essential information for non-destructive identification and also act as helpful references for graphene microstructure optimization with an objective of maximizing certain material properties [32]. In addition, stress components and potential energy under shear stress in low-dimensional and heterogeneous materials are also sensitive to vacancy defects and require more concerns on defect identification and quantification [33]. In the theoretical exploration, the nonlocal elasticity theory is an essential supplement to the finite element method for the impact analysis of atomic vacancy defects [34].…”

“…erties [32]. In addition, stress components and potential energy under shear stress in lowdimensional and heterogeneous materials are also sensitive to vacancy defects and require more concerns on defect identification and quantification [33]. In the theoretical exploration, the nonlocal elasticity theory is an essential supplement to the finite element method for the impact analysis of atomic vacancy defects [34].…”

Negative Thermal Expansion of Carbon Nanotube Bundles

“…To effectively solve these problems, the model of a chain moving on a plane [54][55][56][57] was modified to analyze the mechanical response of the CNT bundle cross section subjected to transverse loading and heating. [58][59][60][61] In this work, using molecular dynamics within the framework of the model of a chain moving on a plane, we calculate the dependence of pressure on temperature in a CNT bundle subjected to biaxial compression. It was unexpectedly found that at a constant volume, the pressure decreases with increasing temperature, which means negative thermal expansion of the CNT bundle.…”

Собственные Частоты Изгибных Колебаний Углеродных Нанотрубок

“…Для расчетов применяется модель цепи, движущейся на плоскости [24,25], которая позволяет для некоторого класса задач многократно уменьшить число рассматриваемых степеней свободы при сохранении высокой точности моделирования механических свойств sp 2 -углеродных материалов. Модель цепи была адаптирована для анализа УНТ в работе [26] и успешно использована для описания механических свойств пучков УНТ при поперечном сжатии [27][28][29][30].…”