Acoustic Performances of Polymers Hierarchical Structure Produced with Material Jetting Technology

This research is aimed at testing the ability of high-end 3D printers to reproduce complex structures having some acoustic performances in terms of sound absorption and sound transmission loss. Specifically, some experiments were made on four different types of geometries to compare their acoustic behaviour. The sound absorption and sound insulation of the samples have been evaluated by means of a four-microphone impedance tube. The adopted technique allows to retrieve the transfer matrix of each specimen and then, through a composition of the matrices, to virtually determine the acoustic performances of any arrangement of the different samples. The experiments revealed promising results in terms of quality, finishing and precision of the jetting process, highlighting benefits and critical issues related to the acoustic performances.