A new method for characterizing and modeling the waviness and alignment of carbon nanotubes in composites

Carbon nanotubes (CNTs) used in engineering composites are mostly wavy. This paper introduces a novel method to characterize the CNT waviness and construct wavy CNT models. The reference waviness was obtained with the aid of micrograph images of CNTs in composites, and an algorithm was developed to construct the corresponding wavy CNTs embedded in a cubic matrix. A model for engineering-scale analysis, capturing the nano-scale CNT-matrix interactions, was then established for characterizing the elastic properties of the CNT composites using the finite element method. It was found that the new characterization method can predict experimental measurements very well, that the CNT waviness greatly influences the elastic properties of a CNT-composite, and that the CNT alignment plays a superior role in altering the elastic properties of the composite.