Sound radiation from plates with elastic boundary conditions embedded in an infinite perforated rigid baffle

Sound radiation from plates with elastic boundary conditions embedded in an infinite perforated rigid baffle (PRB) is analyzed in this paper. Based on the wavenumber domain approach and the solution for transverse vibration of plates with general elastic boundary conditions, the sound power and the radiation efficiency of the plates embedded in the PRB (named ‘PRB-ed plate’ in the following) are derived theoretically. By comparing with the results of sound radiation from baffled and unbaffled plates, it can be found that the PRB-ed plates behave like the dipole source radiation in the fundamental mode region as the perforation in PRB introduces communication of the sound field, while not sufficient to reach the lowest radiation efficiency as unbaffled cases. The parametric analysis of boundary conditions shows that the PRB-ed fully free plate has the lowest radiation efficiency below the critical frequency. For the cases of plates with constraints, the greater the constraints are, the lower the radiation efficiency is in the fundamental mode region, and this order will become totally opposite in the short-circuiting region. Further, the effects of PRB parameters on sound radiation from PRB-ed plates are compared. With the decrease of the PRB thickness and the hole diameter, or the increase of the PRB perforation ratio, the sound power radiated from PRB-ed plates is decreased below the critical frequency. This research could possibly provide ideas on the design of noise control for plate-like structures.