Characteristics Analysis of Acoustic Insulation and Decoupled Tiles by FEM and Experiment

A study of characteristics of acoustic insulation and decoupled tile is carried out in this paper. Based on FEM the numerical computation is firstly applied to an armored plate covered with acoustic insulation and decoupled tiles, on which the cavities are periodically distributed as the incidence of sound wave is at oblique angle. Then taking a large scale double cylindrical structure as an experimental model, the effects of acoustic insulation and decoupled materials on the shell＇s sound radiation are investigated. The working conditions of this experiment consist of all-covered, partially-covered and non-covered. The results of experiment show that when the armored plate set as back lining, the quantity of the tile with cylindrical cavities vary with the increase of the incidence angle and that the resonance frequency keeps constant; At medium and high frequencies, the absorption performance of the tiles subjected to vertical incidence sound wave is the best. When the tiles are underwater, their sound reflections increase with the growth of incidence angle while the transmitted intensity is of inverse. For the single-point mechanical shock excitation, the tiles can effectively suppress the vibration and sound radiation of the double cylindrical shell in the range of medium and high frequencies, on the other hand, the tiles that are applied in the outer and inner shells are more effective. As for the airborne noise, the tiles have obvious effect on the suppression of sound radiation over the full range of frequencies.