Vibration control of submerged plates using active constrained layer damping

This dissertation investigated the fundamentals of controlling the structural vibration and radiated sound of a fluid-loaded plate with one side of the plate in vacuo while the other side is immersed in water. The plate vibration and associated sound radiation were controlled by the use of Active Constrained Layer Damping (ACLD). The ACLD treatment consisted of a conventional passive constrained layer damping patch which was augmented with an adaptive least mean square (LMS) algorithm to control the strain of the constrained layer in response to the structural vibration of or the sound radiation from the plate.;Two experiments were performed which demonstrated the effectiveness of the Filtered-X LMS algorithm controlled ACLD treatment in successfully controlling both the radiated sound from the plate and the vibration amplitude of the plate using either the radiated sound pressure or plate vibration amplitude as the error signal. The ACLD treatment consisted of a viscoelastic damping layer/piezoelectric film constraining layer patch bonded to the in vacuo side of the plate.;The fluid/structure/controller interaction was modeled using the finite element method. The validity of the developed equations in predicting the vibration and sound radiation characteristics of the plate/fluid system was checked experimentally. The effectiveness of the ACLD in damping of the plate vibration and in attenuating the associated sound radiation was demonstrated experimentally for the fundamental mode of vibration of a rectangular aluminum plate mounted on top of a water tank.