Theory and experiments on elastic band gaps

We study elastic band gaps in nonhomogeneous periodic finite media. we stud y elastic band gaps In nonhomogeneous periodic finite media. The finite-dif ference time-domain method is used for the first time in the field of elast ic band-gap materials. It is used to interpret experimental data for two-di mensional systems consisting of cylinders of fluids (Hg, air, and oil) inse rted periodically in a finite slab of aluminum host. The method provides go od convergence, can be applied to realistic finite composite slabs, even to composites with a huge contrast in the elastic parameters of their compone nts, and describes well the experiments.