An acoustically treated structurally reinforced sound absorbing panel
having particular application for use at the inlet cowl of a jet engine to
reduce engine noise leaked into the environment. The sound absorbing panel
includes a sound receiving chamber having a honeycomb shaped core
manufactured from corrugated metallic ribbons. The sound receiving chamber
is sandwiched between a metallic backskin at one side thereof, and a
metallic face sheet at the opposite side. The face sheet is perforated so
that incoming sound waves which represent the engine noise enter the sound
receiving chamber within which they are channeled towards and reflected
between the metallic backskin and face sheet. An acoustic attenuation
medium having a plurality of short metal fibers that are held together by
a sintering process is diffusion bonded to the perforated face sheet so
that the reflected sound waves which are channeled through the sound
receiving chamber are transmitted through and attenuated by the acoustic
attenuation medium.