Prediction of vibro-acoustic response of structure-acoustic strongly coupled cavity

Here, aiming at the problem of response prediction of structure-acoustic strongly coupled cavity under boundary excitation, a response calculation method of coupling system based on energy principle was proposed. Based on the energy principle, the dynamic equation in form of Lagrange function for a structure-acoustic coupled cavity was obtained. According to Rayleigh-Ritz method, Legendre polynomial series was selected to expand the structural displacement function and the sound pressure function of the sound field, the expansions were substituted into the dynamic equation, and the structural vibration and sound pressure response of the cavity were solved. Due to Legendre polynomial satisfying the orthogonality of L2 inner product, high-multiple integral terms in the equation were simplified, and the calculation efficiency was greatly improved. Taking a water-filled rectangular cavity as an example, the correctness of the proposed method was verified by comparing the results obtained using this method with those existing studies and finite element results. The study showed that the transition of structural boundary from strong constraint to weak constraint and decrease in back cavity depth can cause the shift of response peak frequency to lower one; decrease in back cavity depth can also cause increase in energy transmitted from structure to sound field. © 2022, Editorial Office of Journal of Vibration and Shock. All right reserved.