A Basic Study on the Design of Dotted-Art Heterogeneous MPP Sound Absorbers

Recently, dotted-art MPPs have been proposed in which a designed pattern is made with the holes. In such case, MPP becomes heterogeneous general. However, existing theories used for prediction of absorption characteristics assume homogeneity. Therefore, elaboration method needs to be performed. previous work, authors predict by using synthesized impedances each part different parameters; this called synthetic impedance (SIM) present paper. The SIM can potentially various MPPs; however, its scope applicability clarified. Furthermore, proposing design concept MPPs, condition that would make fall within determined. study, order clarify SIM, twelve samples are first prepared, and then measured sound predicted ones compared examined terms errors. results show there two conditions should met produce predictable MPPs: (1) holes distributed over entire surface specimen, (2) hole spacing constant. Considering these conditions, proposed: types holes, larger smaller background, meet above conditions. Case studies nine prototypes predictions fabricated according described above.