TRANSMISSION OF SOUND THROUGH ANISOTROPIC RECTANGULAR PLATES.

A plane sound wave is incident upon an anisotropic rectangular plate set in an otherwise rigid baffle surrounded by a light compressible fluid. In the limit of small wavelengths, compared with plate dimensions, the transmitted sound power is estimated, averaged over a small frequency band and over all possible angles of incidence. Explicit results are presented for a special type of anisotropy, and they have different forms according to whether the operating frequency is above coincidence, below coincidence or within a range of frequencies that corresponds to coincidence. Transition formulae are given for frequencies near the boundaries of the three regimes. The results are extended to allow for more general plate equations.