Page 210 - Carbon Nanotube Fibres and Yarns

200 Carbon Nanotube Fibers and Yarns

Fig. 8.10 Structural evolution of CNT networks under tensile loading, with a strain level
at (A) 0%, (B) 0.051%, (C) 0.456%, (D) 0.962%, (E) 1.368%, and (F) 1.874%, respectively.
(Reproduced with permission from B. Xie, Y. Liu, Y. Ding, Q. Zheng, Z. Xu, Mechanics of carbon
nanotube networks: microstructural evolution and optimal design. Soft Matter 7 (21) (2011)
10039–10047.)

temperatures. Their CGMD simulations revealed that the temperature- and
frequency-invariant hysteresis is due to unstable detachments/attachments
of individual nanotubes in the system induced by the vdW interactions.
Won et al. [119] reported that the zipping and unzipping of adjacent CNTs
and the degree of alignment and entanglement govern the spatially vary-
ing local modulus, providing new strategies to analyze possible dissipation
sources for high vibration damping of CNT assemblies in the future.

8.4.3 Other models

The load transfer in CNT yarns is a complex phenomenon that takes
place at different length scales. Besides the full atomistic simulation and
coarse-grained treatment, a hierarchical model taking into consideration
the morphology-dependent mechanics can also be helpful to understand
the CNT yarn mechanics. Rao et al. [120] presented a coupled analytical
and finite element model of the three-dimensional (3D) morphology and