Numerical Analysis of Acoustic Wave Propagation in Layered Carbon Nanofiber Composites

Here we report on the acoustic wave propagation analyses in a layered nanocomposite structure consisting of the stacks of alternating layers of pure polymer and carbon nanofiber (CNF) reinforced polymer. A gradient in the acoustic impedance has been introduced at the interfaces as a consequence of the discrete heterogeneity of the materials and thus greatly influences the wave prorogation including the reflection and the transmission. In this paper we focus on evaluating the effect of layered structure on acoustic properties of nanocomposites. The transmission has been calculated as a function of the number of the layer repeats at a variety of frequencies. These functions share a common feature that they converge to a particular value asymptotically as the number of the layer repeats increases as if the layered composite is a homogeneous effective medium.