An atomistically-informed multiscale modeling framework to investigate damage evolution and failure in radially-grown carbon nanotube (CNT) architecture is detailed in this paper. Molecular dynamics (MD) simulations are performed to investigate the effects of nano-reinforcements on the elastic-plastic characteristics of the constituent interphase in the radially-grown nanocomposite. An interphase damage model is developed using the continuum damage mechanics approach with damage evolution equations derived using atomistic simulations. The developed damage model is integrated with a high-fidelity micromechanical analysis and captures the underlying physical behavior that could be attributed to the enhancement of the out-of-plane properties at higher length scales. The mechanical properties of the nanocomposite obtained from micromechanical simulations are compared to experimental values reported in the literature, to validate the developed modeling framework. Conclusions are presented by comparing the material response of radially-grown CNT architectures with the traditional fiber reinforced polymer (FRP) with dispersed CNT architecture.

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An atomistic modeling framework to investigate the interface/interphase of composite architecture with carbon fibers containing radially-grown carbon nanotubes (often called fuzzy fibers) is detailed in this paper. A polymeric functional coating for the carbon fiber surface, which also serves as a substrate for the CNT growth, is explicitly modeled. The tensile and transverse moduli of the fuzzy fiber/epoxy interphase is computed from virtual deformation simulations and compared to experimental values reported in literature, in order to validate the nanoscale model. Furthermore, the effect of the polymer substrate is studied by modeling the local interphase mechanics. Various modes of virtual loading provide the cohesive behavior of the local substrate/epoxy interphase. Conclusions are presented by comparing the material response of the interphase with and without the polymeric substrate. The integration of results from the nanoscale to an atomistically-informed subcell-based continuum level model is also demonstrated in the paper.

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A micromechanical modeling framework that integrates an interphase damage model is used to study damage evolution, and failure in radially-grown carbon nanotube (CNT) reinforced nanocomposites. The atomistically-informed damage model is developed using the continuum damage mechanics approach with damage evolution equations derived using molecular dynamics simulations. The developed damage model is integrated with a high-fidelity micromechanical analysis and captures the underlying physical behavior that could be attributed to the enhancement of the out-of-plane properties at the higher length scales. To illustrate the effects of nanoarchitecture, the response of the radially-grown CNT nanocomposite is compared with that of the traditional carbon fiber reinforced polymer (CFRP) composite.@en