Panel dynamic response to a reverberant acoustic field

A novel semianalytical approach based on the integral equation method has been developed to predict the structural response of a panel located in a rigid-walled cavity. This problem is related to the study of the acoustic response of satellite panels with electronic equipment. The main difficulty lies in the treatment of the response of an unbaffled panel, strongly coupled to a high modal density pressure field. A two-indices empty cavity Green's function is used, inspired from electromagnetism. The plate contribution to the sound pressure is obtained by expanding the pressure jump and Green's function on the same basis functions. This approach presents two main advantages : it reduces the size of the linear system to be solved and avoids ill-conditioning problems. This method is found to be quite efficient (10 s per frequency point on a 10 Mflops machine). Results show that the panel responds better at acoustical eigenfrequencies than at its in vacuo modes. The values at which the diffraction phenomena governs the structural and acoustic responses are pointed out in terms of density and flexural rigidity. Finally, the formulation allows the quantification of differences between light and heavy fluid environments.