Patent ID: 11915679
Assignee: MRA SYSTEMS, LLC
Field: Surface technology, coating (Chemistry)
Classification: CPC G  B | IPC B  G

Claim 10:
11. A turbofan engine comprising:
a fan rotor having a plurality of fan blades;
a nacelle surrounding the fan rotor;
a fan duct defined by the nacelle, the fan duct having a duct inner wall; and
an acoustic liner positioned along the duct inner wall of the fan duct, the acoustic liner, comprising:
a face sheet;
a back sheet spaced from the face sheet; and
a core layer defining a cellular structure disposed between the face sheet and the back sheet, the core layer comprising:
a plurality of first resonant cells coupled to the back sheet, each of the first resonant cells comprising:
a first cell wall coupled to the back sheet along a first cell wall base edge, the first cell wall extending from the back sheet toward the face sheet, the first cell wall further coupled to the face sheet along a first cell wall top edge,

wherein the first cell wall of each of the first resonant cells comprises a surface extension that extends from a surface of the first cell wall to a distal end spaced from and disconnected from an opposing first cell wall, the face sheet, and the back sheet.