Active control of the structural and acoustic fields associated with a ribbed plate

[Truncated] The propagation of waves in coupled structures, and the interaction between structural waves and the sound field in the surrounding fluid is an area of increasing importance for engineers. For example, noise and vibration problems arise when a reinforcing rib on a panel effectively scatters the structural waves, resulting in the transmission of vibrational energy as well as the radiation of sound.
In a coupled beam-plate system, the transmission of the plate flexural waves through the reinforcing beam is related to the coupling between the plate flexural waves and the flexural and torsional waves in the beam. The maximum energy transmission through the beam occurs at the optimal coupling between the plate flexural waves and the beam flexural or torsional waves. Active control is applied to the beam to attenuate the far-field flexural energy transmission in the plate. Using information on the physical system, the control system is optimised to achieve the best control performance.