Acoustic Transmission Loss of Perforated Plates

A study has been conducted on the acoustic response of perforated plates at normal incidence. The investigation includes a theoretical analysis of the problem, with validation through experimentation. The acoustic response was quantified through the transmission loss and absorption coefficient of the perforate. The theoretical analysis is based on planar wave propagation through a single contraction/expansion chamber, with modifications to account for hole interaction effects. The resulting formula for transmission loss yields superior predictions over past theories. The theoretical model is validated through rigorous parametric experimentation. Eleven perforated plates with different thickness, hole size, and porosity were tested. Deviations between experiment measurements and theoretical predictions of transmission loss are shown to be less than about one decibel for dimensionless hole diameter d/λ < 0.5. The accuracy of the model does not show a strong dependency on plate thickness or porosity.