Especially for aircraft constructions low weight structures with high sound transmission loss are required. Therefore the aircraft fuselage is build up as a double wall consisting of an outer aluminium skin and an interior lightweight panel. To improve the sound insulation, the cavity between the panels is partially filled with glass wool, which is primarily effective in the high frequency region. To increase the sound transmission loss for low frequencies it is suggested by different authors to use Helmholtz resonators tuned for example to the fundamental mass-air-mass frequency of the partition. Instead of Helmholtz resonators the use of microperforated panel absorbers (MPAs) is theoretically and experimentally investigated in this paper. The sound transmission is calculated for different arrangements of MPAs inside the double wall cavity. An improved sound transmission loss can be obtained for a broader frequency range compared to classical Helmholtz resonators. Further on it is possible to find an optimal design of a MPA for the current layout of the double wall using Maa's theory, which allows an accurate calculation of the acoustic properties of MPAs. Since MPAs can be manufactured of thin plastic foils, they could be used as an additional light weight sound absorber in double-panel partitions.
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