Molecular Dynamics Study on Buckling Behavior of Non-Defective and Defective Triple-Walled Carbon Nanotubes

Abstract

In order to discuss the origin of the buckling of carbon nanotubes from the atomic level, we have performed the compressive simulation of non-defective and defective triplewalled carbon nanotubes (TWCNT) by the molecular dynamics method using the adaptive intermolecular reactive empirical bond order potential, and observed changes in atomic stresses until the buckling. In the non-defective TWCNT, standard deviations of atomic axial stresses rise drastically before the buckling. The transition from homogeneous stress distributions to inhomogeneous ones play an important role in the occurrence of the buckling. In TWCNTs with a vacancy-type defect or a Stone-Wales defect, buckling stresses differ according to location of the defect. Repulsive interlayer interactions caused by the constriction of the outer layer including a defect reduce significantly the buckling strength. On the other hand, constrictions of the middle or inner layer including a defect produce slightly attractive interaction with the outer layer. Therefore, whole layers is buckled at the same time as the buckling of the outer non-defective layers. TWCNTs including many defects that are generated by the heat treatment simulation show smaller buckling stresses than that of TWCNTs including a defect. Defect configurations have a significant influence on distribution of atomic stresses until the buckling. The buckling occurs from constriction parts located close to defects.

Buckling Behavior and Atomic Elastic Stiffness in Defective Multi-Walled Carbon Nanotube under Axial Compression

“…The rapid decrease of the compressive stresses in the MWCNTs is caused by local buckling from these constrictions. In our previous study [8], we suggested that the genesis location of the local buckling is determined by inhomogeneous stress distributions due to the defects. However, the critical stresses or strains relating to the local buckling are dependent upon the structure and location of defects.…”

“…To discuss the origin of CNT buckling from the atomic level, we have performed compressive simulations of non-defective and defective multi-walled CNTs (MWCNTs) via the molecular dynamics method using the adaptive intermolecular reactive empirical bond order (AIREBO) potential [7]. In our previous study [8], we discussed changes in atomic stresses until buckling in triple-walled CNTs. That study suggested that the transition from homogeneous stress distributions to inhomogeneous ones plays an important role in the occurrence of buckling in the MWCNT, though the critical stresses or strains involved in the buckling differ as a function of the structure and location of defects.…”

Some approximate buckling solutions of triple-walled carbon nanotube

“…Batra and Sears [7] used continuum models to analyze the multi-walled carbon nanostructures. The molecular simulations [8,9] provide reliable results in predicting the mechanical/structural behaviors of nanostructures. But due to the substantial computational cost required to carry out the simulations using supercomputers, the continuum models serve as an alternative approach.…”

Effects of Wavenumber and Chirality on the Axial Compressive Behavior of Wavy Carbon Nanotubes: A Molecular Mechanics Study

“…Using atomistic simulations rather than experimental tests, many researchers have analyzed the axial compressive properties of CNTs [6][7][8][9][10][11][12][13]. For example, Sears and Batra analyzed the axial buckling behaviors of pristine, singlewalled (SW), and multiwalled (MW) CNTs [6,7].…”

“…Xin et al studied the axial compressive properties of SWCNTs with vacancies and reported that their compressive strength shows temperature independence [8]. It is noteworthy that the CNTs analyzed by these researchers have defects at only one site along the tube axial direction [6][7][8][9][10][11][12][13]. On the other hand, actual CNTs observed through experiments ( Figure 1) have defects at multiple sites, resulting in a wavy geometry or multiple bending [4,5].…”