Abstract
The transmission characteristics of harmonic elastic waves across a functionally graded layer are studied using the finite element method. The graded layer is oriented normal to the plane incident wave and embedded between dissimilar semi-infinite elastic media. It is assumed that this layer is composed of two phases, and the volume fraction of one phase varies in the thickness direction so that the material properties change between those of the surrounding semi-infinite media. Different microstructures are modeled to represent the volume fraction distribution, namely, a one-dimensional multi-layer as well as granular microstructures with different characteristic sizes. The energy transmission coefficient is obtained as a function of the frequency for the case of Ni-Al_2O_3 graded layer. The present analysis has revealed that different microstructures give quite distinct transmission spectra both qualitatively and quantitatively, even if their averaged distributions of the volume fraction are identical.
