Tailoring Phononic-like topologies for controlling the structural-acoustic coupling in fluid-filled cylinders

Periodic structures exhibit both pass and stop bands and can be utilized for passive control of structural-acoustic coupling in fluid-filled cylinders. Equations of motion of a complex unit cell geometry, incorporating structural-acoustic coupling, are derived by a finite element analysis. It is essential to model unit cells with many degrees of freedom to properly describe the local acoustic impedance. When the structure locale acoustic impedance resembles that of the fluid, the whole structure exhibits significant structural-acoustic coupling effects, and vice versa. By using the Floquet-Bloch theorem and the wave finite element method, the dispersion curves of fluid-filled waveguides can be numerically computed. The present study exploits the sparsity of fluid-filled waveguide model matrices to improve current numerical method. A new factor is presented to quantity the structural-acoustic coupling effect. Several examples which influence the structural-acoustic coupling effect at a desired frequencies range, are described.