Numerical simulation of the effect of nanotube orientation on tensile modulus of carbon-nanotube-reinforced polymer composites

By correlating the curvature of carbon nanotubes to the orientation of fibers in a polymer, the effect of the curvature of nanotubes on the tensile modulus of carbon-nanotube-reinforced polymer composites was investigated with a numerical simulation method. The simulation results showed that the tensile modulus of a nanotube-reinforced composite drops sharply when the nanotubes diverge from their orientation in the axial direction, and the presence of curved nanotubes in the polymer matrix significantly decreases the modulus of the composite. This finding could explain, partly, why in most cases, the predicted tensile modulus of a carbon-nanotube-reinforced composite, based on the assumption that the nanotubes are fully isolated and aligned in the polymer matrix, is much higher than the value obtained from experiments.