The sound absorption of air permeable structures produced by 3D printing using PLA material

Abstract

The aim of the contribution is comparison of noise absorption properties of two designs of acoustic dampening air permeable structures. A circular test samples with a diameter of 89 mm and three different thicknesses of samples were produced using of 3D printing process. In addition to the thickness, the internal structure of the samples was also changed. The prepared samples were tested using an impedance tube. The acoustic properties of the test samples were investigated in accordance with the standards ASTM E1050-19, E2611-17 and ISO 10534-2. A two-microphone method based on the calculation of transfer function method was used to determine the absorption coefficient of the designed structures. The Brüel&Kjær PULSE system was used to estimate the frequency dependence of sound absorption coefficient of test samples. In the paper are presented the experimentally obtained values of the sound absorption coefficient for different structure design and thicknesses of samples produced by 3D printing technology. The measurements were evaluated in the range of working frequencies of the impedance tube.