Abstract: The vibro-acoustic coupling model of acoustic cavity and elastic plate is taken as the research object, and the influences of excitation location, cavity thickness and elastic boundary on acoustic radiation power, surface vibration velocity and sound pressure of elastic plate under point force excitation and point source excitation of the model are compared and analyzed, as well as the differences between the two cases. The vibration displacement function of the plate is obtained by Spectral Geometry Method, in which the coupling between the vibration of the plate and the sound field on both sides of the plate is fully considered by using Hamiltonian principle. The acoustic radiation characteristic parameters of the plate can be calculated by using Rayleigh integral. The results show that the excitation position, the cavity thickness and elastic boundary have different effects on the acoustic radiation power, surface vibration velocity and the sound pressure in the cavity under the point force and point source. When the cavity is thin, several modes of the cavity have obvious influence on the plate under the point force excitation. Under the point source excitation, the coupling effect of the model is more obvious. The sound radiation power, surface vibration velocity and sound pressure in the cavity are mainly affected by the coupling modes, and the coupling effect of the point source is obviously stronger than that of the point force. Compared with torsional stiffness, linear stiffness has greater influence on acoustic radiation.

Key words: cavity-elastic plate model, fully coupled, acoustic radiation characteristic, Rayleigh integral, spectral geometric method