Flexural wave propagation in a fluid-loaded elastic plate with periodically varying rigidity

The method of multiple scales is utilized to analyze the propagation of flexural waves in a fluid-loaded elastic plate with periodically varying rigidity. Subsonic modes are coupled under a Bragg condition imposed by the parametric periodicity, lending to a strong stopband interaction. This interaction is analytically described by two coupled-mode equations. The results might be utilized to avoid the undesirable acoustic radiation occurring when subsonic waves encounter a discontinuity.