Design of 3D carbon nanotube-based nanostructures and prediction of their extra-strong mechanical properties under tension and compression

• A novel 3D nanostructure assembled by connecting CNTs in a new way was proposed.
• Extra-strong mechanical properties of the nanostructure were exhibited.
• Different compressive failure modes such as the local slipping and local buckling were found.

A novel 3D nanostructure which can be potentially applied in reinforcement of composites with enhanced interfacial adhesion is constructed by orderly connecting carbon nanotubes (CNTs) of different lengths. A representative element (RE) of CNTs and unique assembly method of the desired 3D nanostructures are described in detail. It is validated by the first principle that the present nanostructure has stability with a minimum energy of the system. Then the Young’s moduli and strength of the nanostructures under tensile and compressive loads are predicted, using the molecular dynamics (MD) method. Finally, failure modes of the nanostructures are discussed. It is shown that the CNT-based 3D nanostructures have ideal mechanical properties, being superior to those of twisted CNT bundles. The tensile and compressive behaviors and failure modes of the nanostructures depend on the lengths of REs of CNTs.