The effect of physical nonlinearity of the interfacial layer between carbon nanotube and polymer matrix on viscoelastic response of nanocomposite materials under harmonic loading

In present paper, a micro- and macromechanic model is developed to determine the effective nonlinearly viscoelastic response of polymeric nanocomposites reinforced with carbon nanotubes under harmonic loading. By using the correspondence principle in viscoelastic and linearization approach, a three-phase micromechanical model with taking into account the viscoelastic response of the interfacial layer between the reinforcement and the bulk polymer matrix based on the concept of complex moduli is proposed. By employing the present model, the effects of volume fraction of the single-walled carbon nanotubes and also, amplitude of monoharmonic loading on the nonlinear viscoelastic response of polymeric nanocomposites are conducted. For polymeric nanocomposites including unidirectionally aligned carbon nanotubes, numerical results indicate that the effects of both inelastic response of interfacial layer and volume fraction of the single-walled carbon nanotubes on the loss and storage moduli are significantly important. It should be noticed that in mechanical analysis of structural elements made of single-walled carbon nanotubes without consideration of interfacial layer may not give precise predictions. Besides, this paper suggests a new procedure for predicting the complex moduli dependence on frequency and amplitude of strain intensity.