Partial Auxeticity of Laterally Compressed Carbon Nanotube Bundles

Abstract

Carbon nanotubes (CNTs) have attracted increasing attention because of their enormous potential in various technologies. Herein, the evolution of the structure and elastic properties of a CNT bundle under compression in uniaxial and biaxial regimes is analyzed using a chain model with a reduced number of degrees of freedom. The compression stress–strain curves consist of four stages, each of which is characterized by a specific structure and deformation mechanism. In the first stage, all CNTs have the same cross section; in the second stage, the translational symmetry is preserved in the system, but with a doubled translational cell; in the third stage, CNT collapse takes place, leading to the loss of the translational symmetry; the fourth stage begins when all CNTs collapse. Elastic constants are calculated for the CNT bundle under uniaxial and biaxial compression during the first two stages. In all loading schemes, during the second stage of deformation, the CNT bundle exhibits partial auxetic properties. The results obtained contribute to the fundamental knowledge for the design of carbon nanomaterials with enhanced properties.

Cancellation of Auxetic Properties in F.C.C. Hard Sphere Crystals by Hybrid Layer-Channel Nanoinclusions Filled by Hard Spheres of Another Diameter

“…Novel fabrics with auxetic properties [28,29,30,31], targeted for personal applications have been developed. Alongside the experimental studies, new theoretical models exhibiting negative Poisson's ratio [32,33,34,35,36,37,38,39,40,41,42,43,44,45,46] have been proposed. The search for the negative Poisson's ratio in known and naturally occurring materials revealed that around 70% of metals with cubic symmetry have such properties [47].…”

Chirality-Dependent and Intrinsic Auxeticity for Single-Walled Carbon Nanotubes

“…The present work not only reveals chiral-dependent insights of mechanical properties of SWCNTs, but also first discovered the auxetic phenomenon of perfect SWCNT. It is believed that with these new findings, our work will contribute to future study and application of SWCNTs [45,46].…”

Poisson's Ratio of f.c.c. Hard‐Sphere Crystals with Cubic Supercells Containing Four Nanochannels Filled by Hard Spheres of Another Diameter

“…[19,20] In this work, we use the more recent classification [20] which distinguishes between nonauxetics, partial auxetics, and auxetics. Vast potential applications of auxetic materials drive the theoretical and experimental investigations, which branch into auxetic metamaterials, [21][22][23][24][25][26][27][28] models, [16,[29][30][31][32][33][34][35][36][37][38][39][40][41] structures, [42][43][44][45][46][47][48] polymers, [49,50] composites, [51] foams, [52][53][54] and fabrics. [55][56][57][58] Most of the research on auxetics is focused either on developing new materials or searching for auxetic properties in existing ones.…”