IMPACT RESISTANCE ACOUSTIC TREATMENT

摘要

A liner assembly for a duct includes noise attenuation panel for dissipati ng sound energy generated within the duct. A damage resistant acoustic panel fo r installation in high velocity impact prone locations includes a plurality of openings for communicating noise signals to the noise attenuation panel. At lease som e of the openings includes a first diameter that extends a depth into the acoustic panel. The depth is no greater than the first diameter. A second portion extends the remainder of the thickness into the acoustic panel and includes a diameter greater tha n the first diameter. The increased area provided by the second diameter reduces restriction to the transmission of sound energy to the noise attenuation panel within an acoustic panel thickness required for protecting against foreign object damage.