The Estimation of the Sound Power Radiated from Modified Structures by the Modal Synthesis Method

This paper describes the estimation of the sound power radiated from a modified structure using an aluminum plate es asimple example. The modal parameters of the original, unmodified aluminum plate are first determined by the experimental modal analysis. Second, those of the modified aluminum plate are calculated by the Modal Synthesis Method. Using these obtained modal parameters, the three factors for estimation total loss factor, radiation loss factor, and driving point mobility are calculated for the or@inal and modified aluminum plates, respectively. The sound powers radiated from the original and modified aluminum plates are estimated by giving en exciting force. Comparison of the estimated sound power changes with the measured changes obtained by the sound intensity method shows that the tendencies of the changes caused by the modffication are well estimated. The Medal Synthesis Method is hence effective to estimate the sound power after structural modification.