Directionality of flexural intensity in orthotropic plates

This work investigates composite plates and their ability to direct flexural intensity, which has important implications for noise and vibration control. It is well known that a composite plate supports a flexural wave whose wavenumber depends strongly on its angle of propagation. This suggests that a composite plate will direct more flexural intensity in some directions than others. The present work considers a thin multi-layered plate in which each layer is constructed from an orthotropic material and has a chosen orientation relative to the other layers. Such an approach may be used to design highly directive structures. An analysis is presented in which a two-dimensional Fourier transform is analytically applied to the equation of motion, yielding algebraic expressions for displacements and stress resultants. Next, a two-dimensional discrete inverse Fourier transform is applied to compute displacements and stress resultants at discrete locations. Flexural intensity is computed at these locations. (C) 2011 Acoustical Society of America. [DOI: 10.1121/1.3531837]