| 摘要 |
Airborne resonance buildup (in directions parallel with and/or at acute angles to the first and second major skins or panels of enclosed cavities) is damped by locating anisotropic porous damping materials within the cavity between the first and second major skins or panels of the cavities. In one preferred embodiment, one or more anisotropic fibrous blankets are located between the skins of a cavity with the fibers of the blanket(s) lying in planes generally perpendicular to the first and second skins and parallel to one pair of the sidewalls of the cavity. In another embodiment, layered insulation modules of insulation blankets are located in the cavity in a checkerboard or parquet pattern so that the fibers in the insulation blankets of a first set of modules lie in planes extending generally perpendicular to a first opposed pair of cavity sidewalls and the fibers in the insulation blankets of a second set of modules lie in planes extending generally perpendicular to a second opposed pair of cavity sidewalls. In another embodiment, only the perimeter of the cavity is insulated with the fibrous insulation blanket(s) and a non-insulated generally centrally located air space, within the cavity, extends between the skins of the cavity and has a perimeter defined, at least in part, by spaced apart, opposed surfaces of the fibrous insulation blanket(s).
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