Damping Characteristics of Carbon Nanotube-Epoxy Composites via Multiscale Analysis

Abstract

In this paper, the damping characteristics of epoxy resin containing aligned or randomly oriented carbon nanotube (CNT) ropes are investigated via a multiscale analysis approach. The shear strengths at the inter-tube and tube-resi n interfaces are calculated using molecular dynamics simulations of nanotube pullouts before being applied to a micromechanical damping model. In the micromechanical model, the composite is described as a three-phase system composed of a resin, a resi n sheath acting as a shear transfer zone, and a carbon nanotube rope. The concept of stick-slip motion is used to describe the load transfer behavior between carbon nanotubes in a rope as well as between nanotubes and the surrounding sheath. Both the energy dissipations f rom the viscoelastic polymer matrix and from the stick-slip motion are included in the over all structural damping characteristics. The effect of nanorope alignment on damping characteristics is also presented. Nomenclature 1 E = Young’s modulus in three-element standard solid model for viscoelastic resin 2 E = Young’s modulus in three-element standard solid model for viscoelastic resin eq E = equivalent Yong’s modulus for carbon nanotube as a solid cylinder rp f = volume fraction of carbon nanotube rope G = complex shear modulus of viscoelastic resin eq G = equivalent shear modulus for carbon nanotube as a solid cylinder K = bulk modulus of viscoelastic resin a L = length of composite unit cell nt L = length of carbon nanotube eff t s l - = effective length of SWNT/sheath debonding nt R = radius of carbon nanotube rp R = radius of carbon nanotube rope sh R = outer radius of the sheath a