Modeling the influence of interphase on the elastic properties of carbon nanotube composites

This work investigates the influence of the interphase on the effective properties of carbon nanotube (CNT) composites using finite element analysis and elasticity solutions for representative volume elements. The influence of interphase thickness and gradient in elastic modulus on the elastic properties and stress distribution of the composite is examined, in order to shed some light on experimental parameters that are difficult to measure. It is found that the thickness of the interphase strongly influences the elastic properties and stress distribution of the composite, especially for matrices with low elastic modulus. Modeling results also suggests that the interphase thickness in CNT nanocomposites should be at least of the order of the CNT thickness and that the interphase modulus may follow an exponential gradient.