Multiple Scattering of Waves in Irregularly Laminated Composites

The transition matrix formulation of multiple scattering is applied to the problem of wave propagation in a one-dimensional layered medium. The effect of geometrical irregularity in an otherwise periodic layered structure is investigated in detail for the case of elastic waves propagating normally to elastic layers embedded in elastic, or in viscoelastic matrix media. The irregularity is found to widen and diminish the stop bands and soften the sharp band features characteristic of a fully periodic structure, and to generate scattering losses with a consequent increase in the attenuation of the coherent wave field.