A DESIGN METHOD FOR MINIMIZING THE SOUND POWER RADIATED FROM PLATES BY ADDING OPTIMALLY SIZED, DISCRETE MASSES

In this paper a novel method for minimizing the sound power radiated f rom a structure is presented. The method involves placing strategicall y sized masses at specific locations on the structure's surface. The m inimization procedure modifies the shapes of the resonant modes of the structure in the frequency range of interest such that they are force d to radiate sound inefficiently. Because of this, they are referred t o as ''weak radiator'' mode shapes. The method uses an optimization pr ocedure that directly minimizes the radiated sound power from the surf ace of a plate in an infinite baffle. The procedure can be carried out for a single frequency or over a range of frequencies. Analytical sen sitivities of sound power with respect to the design variables are dev eloped and used in the optimization algorithm. Results on various test cases show sound power reductions of 10 dB or more even when several resonances are included in the frequency band. An acoustic intensity p robe is used to experimentally verify the results for one test case. T he experiment confirms the sound power reductions predicted by the opt imization program.