A Shear-Lag Model for Nanotube-Reinforced Composite Systems Under Transient Heat Transfer

Understanding the stress transfer between nanotube reinforcements and matrix is an important factor in determining the overall mechanical properties of nanotube-reinforced composites. The classical shear-lag model in which the fiber and the matrix are equally long can not be applied to nanotube-based composite structures. Recently, a shear-lag model under mechanical loading for a concentric composite cylinder embedded with a capped nanotube has been introduced as the representative volume element (RVE). In this study, using similar approach the shear lag model is extended for a system under both mechanical and thermal loadings. The outer surface of RVE is prescribed to heating and cooling conditions, and transient heat transfer concept is used to find the temperature distribution in the matrix and on the surface of the nanotube. Using constitutive, geometrical and equilibrium equations for a given RVE, new shear-lag model for a nanotube-reinforced composite is then derived. It is demonstrated that the proposed model at room temperature could reduce to the same results obtained previously. These equations can be used to predict the mechanical properties of nanocomposite systems in real applications.