Coupled thermomechanics of single-wall carbon nanotubes

Abstract

The temperature-dependent transverse mechanical properties of single-walled nanotubes are studied using a molecular mechanics approach. The stretching and bond angle force constants describing the mechanical behaviour of the sp 2 bonds are resolved in the temperature range between 0 K and 1600 K, allowing to identify a temperature dependence of the nanotubes wall thickness. We observe a decrease of the stiffness properties (axial and shear Young's modulus) with increasing temperatures, and an augmentation of the transverse Poisson's ratio, with magnitudes depending on the chirality of the nanotube. Our closed-form predictions compare well with existing Molecular

Temperature insensitive negative Poisson's ratios in isotropic alloys near a morphotropic phase boundary

“…7 For carbon nanotubes, Poisson's ratio becomes small but still positive as the chirality increases. 8 In highly oriented nanotube structures, negative Poisson's ratio (auxetic behavior) has been reported 9,10 based on orientation of the tubes. Anisotropic solids exhibit effects such as stretchtwist coupling, so negative Poisson's ratio is not so counterintuitive in such solids.…”

Modeling of thermomechanical properties of polymeric hybrid nanocomposites

“… are listed in Table . The variation of CTEs of the armchair (10, 10) CNT with the temperature deviation is considered here but the elastic properties of CNTs and polymer are reported to be marginally dependent on the temperature deviation . Hence, the temperature dependence of the elastic properties of the constituent phases of FFC is neglected.…”

Graphene nanofilm as pressure and force sensor: A mechanical analysis

“…For the specific calculation of the hinging constant the Reader can consult Refs. . The tensile rigidity calculated using the atomistic–continuum approach of Eqs.…”

“…In this work, we use an atomistic–finite element (FE) approach to model the nonlinear out‐of‐plane mechanical behaviour of rectangular graphene sheets with different aspect ratios subjected to both central and distributed loading. The atomistic–FE approach used in this work has been used to simulate the mechanical properties of carbon nanotubes , single () and bilayer graphene (). A peculiarity of this modelling approach consists in identifying the distribution of average equilibrium lengths of the sp 2 bonds, as well as the value of the thickness of the nanostructure minimising the total potential energy of the system, resolving therefore the so‐called ‘Yakobson's paradox’ (), and an enhanced identification of the engineering constants of the nanomaterial.…”