Abstract: Controlling the acoustic radiation modes amplitude of a vibrating plate has previously been shown to be a good strategy to reduce its overall sound radiation. With the examples of the laminated composite plate, a new piezoelectric sensor design is presented to measure the acoustic radiation modes amplitude. The output signals of the PVDF films are multiplied by appropriate weights so that the weighted combination of the outputs directly leads to the acoustic radiation modes amplitude. The weighted coefficient depends on the vibrating modal expression of the laminated composite plate. Because of the complexity of kinetics analysis of the actual laminated composite plate, the combination of the layered theory with finite element will be used to process the vibration of laminated composite plates. The expressions of the structural mode are obtained by curve fitting to discrete modes. The analysis shows that it is feasible to measure the structure mode and the acoustic radiation modes amplitude of vibrating structure. The analysis and the comparison between the numerical results and the experimental data are given.

Key words: laminated composite plates;radiation modes;layer wise theory;piezoelectric sensors