Investigation of the vibration response and sound transmisson of a micro-perforated plate periodically stiffened by two sets of orthogonal beams

A semi-analytical method to estimate the vibration response and sound transmission of an infinite micro-perforated plate, stiffened by two periodic sets of orthogonal beams, is proposed in this paper. The plate is submerged in water fluid and excited by a plane wave at arbitrary angle of incidence. Based on the velocity boundary condition and acoustic impedance of the micro-perforated plate, the equation of the vibration response of the studied structure is established, which is then expressed in terms of an infinite set of space harmonic amplitudes using the Fourier transforms and space harmonic method. After solving these space harmonic amplitudes numerically, the vibration response and sound transmission coefficient of the perforated plate in the physical space are finally obtained by employing the Fourier inverse transform. Comparisons with sound pressure results of the unstiffened perforated plate of Takahashi illustrate the validity of the proposed approach. In numerical examples, effects of the perforation ratio and periodic beams on the vibration response and acoustic transmission coefficient are investigated.