Band gaps and elastic waves in disordered stacks: normal incidence

We present a development of previous work where we studied the reflection and transmission properties of an array of circular cylindrical voids in an elastic matrix. The voids were taken to be infinitely long, equally spaced and of the same radius. In this paper we improve the method to deal with the problems of inclusions as well as voids and study various forms of disorder within the array, as well as stack designs showing good low–pass and band–pass characteristics in transmission.