53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
23 - 26 April 2012, Honolulu, Hawaii

AIAA 2012-1825

Effect of nanoscale fillers on the viscoelasticity of polymer nanocomposites

Mohammad Bonakdar, G.D. Seidel
Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061-0203, USA

and D.J. Inman
University of Michigan, Ann Arbor, MI

For viscoelastic materials the stiffness and loss properties directly depend on not only strain but also strain rate and implicitly depend on temperature via time temperature superposition, which in case of harmonic loading leads to frequency dependent response. For viscoelastic composites in which at least one of the constituent materials is viscoelastic, there is great utility in the ability to predict the effective dynamic mechanical properties as a function of the constituent phase properties and geometry. The presence of different concentrations of nanofillers not only directly impacts the nanocomposite effective properties, but also contributes to the formation of an interphase layer, which also has a very strong influence on the effective properties. The interphase layer usually has properties which are distinct from that of the particle and the matrix phases. In this paper micromechanical methods combined with the correspondence principle of viscoelasticity are used to obtain the effective damping properties of viscoelastic composites. The interphase layer is modeled using the composite cylinder model and the composite sphere model and its effect on the overall stiffness and damping of the composite is investigated.