Effects of interfacial friction on the damping characteristics of composites containing randomly oriented carbon nanotube ropes

This article presents a model for describing the damping characteristics of uniaxially stressed polymeric composites filled with randomly oriented single-wall nanotube (SWNT) ropes. A close-packed lattice consisting of seven nanotubes in hexagonal array is used to present the nanoropes. The composite is described as a three-phase system composed of a resin, a resin sheath acting as a shear transfer zone, and SWNT ropes. The concept of 'stick-slip' motion caused by frictional contacts is proposed to describe the load transfer behavior between individual nanotubes and between a nanotube rope and a sheath. The results of the analytical study show that both the Young's modulus and the loss factor of the composite are sensitive to stress magnitude. Also, to show the inter-tube sliding effects due to nanotube aggregation, the Young's moduli and the loss factors of composites filled with aligned SWNTs, aligned nanoropes, and randomly oriented nanoropes are compared.