Multiscale Analysis of Fracture of Carbon Nanotubes Embedded in Composites

Abstract

Abstract. Due to the enormous difference in the scales involved in correlating the macroscopic properties with the micro-and nano-physical mechanisms of carbon nanotube-reinforced composites, multiscale mechanics analysis is of considerable interest. A hybrid atomistic/continuum mechanics method is established in the present paper to study the deformation and fracture behaviors of carbon nanotubes (CNTs) in composites. The unit cell containing a CNT embedded in a matrix is divided in three regions, which are simulated by the atomic-potential method, the continuum method based on the modified Cauchy-Born rule, and the classical continuum mechanics, respectively. The effect of CNT interaction is taken into account via the Mori-Tanaka effective field method of micromechanics. This method not only can predict the formation of Stone-Wales (5-7-7-5) defects, but also simulate the subsequent deformation and fracture process of CNTs. It is found that the critical strain of defect nucleation in a CNT is sensitive to its chiral angle but not to its diameter. The critical strain of Stone-Wales defect formation of zigzag CNTs is nearly twice that of armchair CNTs. Due to the constraint effect of matrix, the CNTs embedded in a composite are easier to fracture in comparison with those not embedded. With the increase in the Young's modulus of the matrix, the critical breaking strain of CNTs decreases.

Mesoscale modeling of mechanics of carbon nanotubes: Self-assembly, self-folding, and fracture

“…[9][10][11][12][13] Most studies in the literature that focused on CNTs have considered only small-aspect ratio CNTs or a small number of interacting CNTs. In contrast, experiments have shown that single wall carbon nanotubes (SWNTs) can grow to lengths above 700 nm with a diameter of 0.9 nm, resulting in an aspect ratio as large as about 800.…”

Nanoscopic observations for evaluating the failure process of aligned multi-walled carbon nanotube/epoxy composites

“…Niaki et al [34] also simulated the fracture process of graphene sheet and SWNTs using a similar approach and reported that dynamic fracture stresses were, respectively, determined approximately 115 GPa and 122 GPa for different sizes of graphene sheet and armchair CNTs. A multiscale mechanics method used to study the deformation and fracture of CNTs embedded in a composite was presented by D. L. Shi et al [35], who reported that the critical strain of defect nucleation of a CNT is sensitive to its chiral angle, but not to its diameter and that the constraint effect of matrix makes the CNTs easier to fracture. They also simulated the effect of some other factors such as the waviness of CNTs, the CNT-matrix interface adhesion, and the distributed residual stresses in composites.…”

Mechanical property of carbon nanotubes with intramolecular junctions: Molecular dynamics simulations

“…Since their discovery in 1991 [1], carbon nanotubes (CNTs) have become a closely watched frontier in many scientific and technological fields due to their striking structure and superior mechanical, physical, and chemical properties [2][3][4][5][6][7][8][9]. They possess extremely high tensile Young's modulus of about 1 TPa or above, and chirality-dependent electrical conductivity [4][5][6][7][8][9][10][11][12][13][14].…”

“…They possess extremely high tensile Young's modulus of about 1 TPa or above, and chirality-dependent electrical conductivity [4][5][6][7][8][9][10][11][12][13][14]. Intramolecular junctions (IMJs), which seamlessly fuse two different CNTs together, have also been proposed to display a range of other interesting functions, different from the constituent CNTs [14][15][16][17][18][19][20][21][22][23][24][25].…”