▎ 摘　　要

In this paper, we have evaluated the strength of a graphene/nanotube bundle considering the two possible failure mechanisms, i.e. intrinsic fracture or sliding. We have accordingly proposed smart strengthening strategies, such as a flaw tolerant design and the nanotube self-collapse. The flaw tolerant design reduces the required strength whereas the self-collapse can increase the achievable strength. Only by coupling these complementary, and possibly other e.g. self-healing, smart strategies, the Artsutanov's dream of the space elevator could be realized. The ultimate design of a 35 GPa strong tether is thus proposed for the first time in this paper, thanks to graphene bundles and the numerous previous investigations performed by the author. Graphene bundles and composites, in which sliding is the current weakest link, are demonstrated to be two times stronger than their nanotube counterparts. (c) 2012 Elsevier Ltd. All rights reserved.