Role of nanotube chirality on the mechanical characteristics of pillared graphene

YW Lin and K Xu and XZ Cao and ZS Zhang and JY Wu, MECHANICS OF MATERIALS, 162, 104035 (2021).

DOI: 10.1016/j.mechmat.2021.104035

Pillared graphene composed of carbon nanotubes (CNTs) and graphene sheets shows a host of robust properties with diverse applications. Herein, mechanical characteristics of pillared graphene composed of six different chiral CNTs are explored using molecular dynamic (MD) simulations. Pillared graphene shows distinct tensile and compression mechanical characteristics that are greatly dictated by the chirality of CNT pillars. Subjected to planar and CNT-axial directional loads, (6,6) and (8,4) chiral CNTs-dominated pillared graphene are the most mechanically robust structures in terms of tensile strength. Upon compression, four distinct loading stages, including elastic compression, progressive compression, collapse of CNTs and densification, can be identified from their loading curves and re- alignment analysis of CNTs. Besides wrinkling of graphene, compression- induced structural transformations are quantitatively explained by inclination of CNTs in pillared graphene. As a result of de- wrinkling/wrinkling behaviors of graphene sheets, specific pillared graphene structures yield negative Poisson's ratio. Analysis of compression energy-absorption indicators such as crush force efficiency, stroke efficiency and specific energy-absorption reveal that they are good energy-absorbers, with the highest performance of energy-absorption for (7,5) CNT-dominated pillared graphene. The study provides critical un-derstanding of role of CNT chirality on the mechanical properties of pillared graphene for optimal design of high-dimensional hybrid CNT- graphene structures with high mechanical performance.

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