Characterization of sonic crystal acoustic absorbers produced by fugitive ink manufacturing process

A comprehensive study of the acoustic absorption of sonic crystals composed by a regular arrangement of columns, with the sound wave propagating parallel to the crystals, was conducted. A model correlating the structure parameters with the parameters of the well-known JCAL acoustic model was developed. The absorption of structures with low and high porosity were compared. In order to produce broadband acoustic absorption, porosity should be high and the space between crystals should be small favorizing the friction of the propagating medium with the wall of the crystals and consequent wave dissipation. Based on advanced techniques used to produce microscopic biomedical devices, a process to manufacture sonic crystals was developed. Two samples were produced. Acoustic absorption was assessed in a 30mm impedance tube. Experimental and simulated acoustic absorption was compared and discussed.