Perforated Core Liner Assembly for Turbofan Noise and Drag

Instead of forming holes in the facesheet to achieve acoustic performance, the patent inverts the approach by using a perforated core structure. The core has perforations that allow sound waves to pass through, while the facesheet remains solid or has minimal openings. This inversion eliminates the need for extensive hole formation in the facesheet, thereby reducing surface drag while maintaining noise attenuation capability.

The patent introduces a perforated core as an intermediary structure between the facesheet and the acoustic environment. This core with its perforations serves as the primary acoustic attenuation mechanism, mediating the sound wave interaction. By placing the perforations in the core rather than the facesheet, the design achieves acoustic performance without compromising the facesheet's aerodynamic efficiency.

The patent inverts the conventional approach by placing perforations in the core structure rather than forming them in the facesheet. This inversion significantly simplifies manufacturing, as the facesheet can be produced with minimal or no openings using standard fabrication processes, while the core's perforations are formed as part of its structural assembly. This reduces both manufacturing cost and time requirements.

The patent segments the acoustic attenuation function from the facesheet by implementing a separate perforated core structure. This segmentation allows the facesheet to be manufactured independently with simple processes, while the core handles the acoustic perforation requirements. The modular design enables separate optimization and assembly, reducing overall manufacturing complexity and time.