Elastic wave band gaps of one-dimensional phononic crystals with functionally graded materials

The propagation of elastic waves in one-dimensional (1D) phononic crystals (PCs) with functionally graded materials (FGMs) is studied using the spectral finite elements and transfer matrix methods. FGMs typically treat the graded interlayer as a system of discrete layers, and the material properties are varied according to a well-known rule, such as the power law. The 1D PCs are composed of both FGMs and isotropic materials, and their band gaps can be changed with different FGM compositions and geometry parameters. By selecting the appropriate parameters, the desired filters can be designed.