Micromechanical modeling of carbon nanotube – polymer composites

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2018
Taç, Vahidullah
A micromechanics-based model is developed to simulate carbon nanotube – polymer nanocomposites and analyze its mechanical behavior. The nanocomposite is first divided into four distinct regions, or phases, based on mechanical behavior and density; the carbon nanotube, the interface, the interphase and the polymer. The finite element method was later used to combine the nanotube and interface phases into an effective fiber for better representation and incorporation of their roles and constitutive properties in the micromechanical model. The elastic moduli of the interphase were modelled in a position dependent manner to better represent its true nature. Parametric studies were performed on the model and the results were compared with the previous work in the literature. The four phases were each found to have significant effects on the behavior of the nanocomposite. It was observed that when a soft interface model is used, the direct effect of the carbon nanotube on the stiffness of the nanocomposite vanishes, and the interphase becomes the sole reinforcement phase in the composite. Whereas in the case of a stiff interface the CNT significantly affects the mechanical properties of the composite through the effective fiber. Thinner but longer carbon nanotubes were found to better enhance the stiffness of the nanocomposite compared to thick and short nanotubes.