Effect of perforation hole shape and angle on sound absorption in perforated plastic panels

Abstract

This study investigates the influence of hole shape on the sound absorption performance of perforated plastic panels. Circular, square, diamond, and teardrop curve shapes were selected for this study. A series of experimental measurements were conducted using the standard impedance tube transfer function method. The acoustic behaviour of each configuration was analysed in the 50–5000 Hz frequency range. The results indicate that the shape of the perforation holes significantly affects the absorption characteristics, particularly in the high-frequency range. Panels with optimised geometries demonstrated enhanced sound absorption, suggesting that the shape of the perforation hole can improve the acoustic efficiency of lightweight plastic materials. The thickness of all panels and the hole size were kept constant to 20,0 and 3,0 mm, respectively. For all perforation hole shapes, results showed that the sound absorption peak was achieved at 4000 Hz. The highest peak sound absorption was 0.85 when measured on a panel with holes of the shape of square. The aim of this study was to find the correlation between sound absorption and the shape of the perforation hole.