The journal Nanomaterials published the results of the study of the torsion properties of carbon nanotube bundles by the AIREBO method in the LAMMPS software package. The study was performed in collaboration with members of the research team of Dr. Haifei Zhang (Zhejiang University, Hangzhou, China).
Based on atomistic simulations, this work systematically investigates the torsional properties of CNT bundles with different constituent CNTs. Generally, the bundles exhibit a multiple-step fracture behavior due to the uneven torsion-induced tensile stress, i.e., the outer CNTs experience fracture first. The chirality of CNTs, diameter ratio of the constituent CNTs and the mass density of the bundle structures induce significant influence on the torsional properties of the bundle. It is found that a larger diameter ratio exerts a negative effect on the gravimetric energy density (elastic limit) of the bundle structure, but it enhances the elastic constant. The different packing morphologies of the bundle structure with the same components induce a 30% difference to the gravimetric energy density, a 16% and 19% difference to elastic limit and elastic constants, respectively. Specifically, the elastic constant increases as the effective diameter of bundle structures rise, and the relative difference of the elastic constant for the bundle with different mass density decreases from 73% to 53%. Additionally, separate fracture of the outer and inner wall is found in the DWNT-based bundles, resulting in lower gravimetric energy density and elastic limit than those of the SWNT-based bundles. In summary, this work provides a comprehensive understanding of the impacts of microstructure on the torsional properties of CNT bundles.
This is the first joint publication of the scientific groups of Professor O.E.Glukhova and Dr. Zhan. In the future, it is planned to submit a collaborative project to International S&T Cooperation Program of China.
The article can be found on the website: https://www.mdpi.com/2079-4991/12/5/760