Abstract:

A systematic method based on optimization techniques has been developed to determine locations of absorbers or concentrated masses required to reduce the vibration level, surface sound-pressure level, and total acoustic radiation power from a fluid-loaded structure. The method is demonstrated using a simply supported, fluid-loaded beam driven by a harmonic point force. In the optimization procedure, the unequally spaced absorbers or concentrated mass locations are the design variables and the designated location of vibration level, surface pressure, and the radiated acoustic power serve as the objective functions, respectively. Results show that the displacement response, surface sound pressure, and total radiated acoustic power can be reduced or controlled due to the presence of the absorbers or concentrated masses in an optimal arrangement. Although the reduction in vibroacoustic response achieved through concentrated masses is not as efficient as that of absorbers (as expected) satisfactory results in local vibration and surface sound pressure confinement are achieved using the concentrated masses. Note that the structure demonstrated here is simple, but it is believed that this methodology can be simply applied to other complex fluid-loaded structures. [Work supported by NSC, Taiwan.]