Mechanical Response of Carbon Nanotube Bundle to Lateral Compression

Abstract

Structure evolution and mechanical response of the carbon nanotube (CNT) bundle under lateral biaxial compression is investigated in plane strain conditions using the chain model. In this model, tensile and bending rigidity of CTN walls, and the van der Waals interactions between them are taken into account. Initially the bundle in cross section is a triangular lattice of circular zigzag CNTs. Under increasing strain control compression, several structure transformations are observed. Firstly, the second-order phase transition leads to the crystalline structure with doubled translational cell. Then the first-order phase transition takes place with the appearance of collapsed CNTs. Further compression results in increase of the fraction of collapsed CNTs at nearly constant compressive stress and eventually all CNTs collapse. It is found that the potential energy of the CNT bundle during deformation changes mainly due to bending of CNT walls, while the contribution from the walls tension-compression and from the van der Waals energies is considerably smaller.

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

“…Note that the deformation is performed up to the compressive biaxial volumetric strain |θ | ≤ 0.1 to avoid the first-order phase transition related to a formation of the collapsed CNTs, as revealed in Ref. [55].…”

“…For further details related to the simulation setup and construction of the Hamiltonian of the chain model, we refer the reader to our previous publications [53][54][55].…”

“…[47] has been applied successfully to the investigation of structure and properties of carbon nanoribbons [47][48][49][50][51] and dynamics of surface ripplocations [52]. Recently, the chain model has been used for simulation of evolution of CNT bundle structure under both lateral uniaxial and biaxial compression [53][54][55].…”

Собственные Частоты Изгибных Колебаний Углеродных Нанотрубок

“…представляющим сумму кинетической энергии, энергии валентных связей и валентных углов (их выражения приводятся в [29], а также ниже для удобства читателя).…”

“…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].…”