Wave Propagation in a Layer Containing a Random or Periodic Distribution of Inclusions

Wave propagation through paniculate composites has received an increased amount of attention in recent years. One of the earlier studies on this subject was presented almost 50 years ago. Albert Wolf modeled the motion of a single rigid spherical inclusion in an elastic medium [1]. Later, Mow investigated scattering by a single elastic or fluid inclusion [2]. In 1970, Moon and Mow calculated a cutoff frequency for a random dispersion of rigid spherical inclusions in an elastic medium [3]. The subject of wave propagation through particulate composites was studied experimentally by Kinra, et al. in a series of papers examining dispersive wave propagation through particulate composites with both random and periodic distributions [4–9]. The results from one of these papers, Kinra and Ker [8], are presented in Figures 1 and 2. Figure 1 shows the phase velocity versus frequency for periodic and random steel/PMMA composites. Figure 2 shows the attenuation of the same composites. Notice that phase velocity discontinuities occur at the same frequencies as local peaks in the attenuation