The design of strongly bonded nanoarchitected carbon materials for high specific strength and modulus

Understanding the structure-mechanics relationships in cellular solids is essential for using the same material to achieve better mechanics. We use multiscale modeling and computation to investigate the mechanics of a series of hierarchical carbon nanoarchitectures with structural features quantitatively characterized. We find that the Young's modulus and tensile strength of the graphene network are mainly determined by its density. However, different density scaling laws of compressive strength are observed and they are related to the length, diameter, and surface roughness of the constituent struts, the buckling form of which yields different scaling laws. Therein, the graphene network with struts of a higher length-to-diameter ratio, smoother surface, and failure mode of shell buckling has a higher compressive strength for a given overall density and topology. Besides, the topology, bonding mode, and multiscale defects explain the large variance of scaling laws of different carbon materials. The work reveals the great potential of architected cellular carbons and provides insight into their future design.