INSERTION LOSS OF A CAVITY-BACKED SEMI-CYLINDRICAL ENCLOSURE PANEL

In this paper, the insertion loss of a cavity-backed semi-cylindrical enclosure panel is studied theoretically and experimentally. The classical approach based on Narayanan [1] and Lee [2] is employed to the semi-cylindrical enclosure modelling. The theoretical model considers the three-dimensional acoustic modes of the semi-cylindrical cavity and the noise source vibration mode shape. The experimental result agrees reasonably with the theoretical prediction. It is found that the higher structural resonance in the semi-cylindrical can significantly deteriorate the insertion loss performance while only the (1,1) mode structural resonance in the rectangular models is the important one. The noise source panel vibrating in the (3,1) mode shape induces higher air pressure on the semi-cylindrical panel through the air cavity than the (1,1) mode shape.