Numerical investigation of composite materials reinforced with waved carbon nanotubes

Abstract

This paper studies the extent to which the effective stiffness of composite materials can be impacted by the characteristic waviness of nanotubes embedded in polymers. A three-dimensional finite element model is used to investigate the effect of volume fraction and waviness on mechanical properties, i.e. Young’s modulus and Poisson’s ratio, of composites reinforced with waved carbon nanotubes. According to the obtained results, the nanotube waviness causes a decrease in the longitudinal and transverse Young’s modulus of composites, compared to the straight nanotube reinforcement, but the change in the value of transverse Young’s modulus (E_yy) is less remarkable than the longitudinal Young’s modulus (E_xx). Furthermore, the effect of fiber curvature on Poisson’s ratio has also been studied. The results show that the curvature has not much effect on Poisson’s ratio and when a fiber curvature changes, Poisson’s ratio value almost remains unchanged. In addition, the effect of fiber volume fraction on the longitudinal Young’s modulus and major Poisson’s ratio has been studied. As the mesh density may have a significant role in evaluating the model, several different meshes have been generated in order to predict their effect on the mechanical properties of the composite.