Aircraft Acoustic Panel With Variable-Height Cells for Broadband Attenuation
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Solution Overview
Problem
Existing acoustic panels for aircraft propulsion systems require improvement in sound attenuation efficiency and mass reduction.
Innovation Solution
The acoustic panel features a perforated skin with interspersed first and second cells, each with distinct vertical heights and fluidly coupled cavities, designed to attenuate sound waves through destructive interference and reduce overall mass by varying cell heights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform cell heights are used in acoustic panels, then manufacturing is simplified, but sound attenuation efficiency across multiple frequencies is reduced
Solution Approach 1:
The acoustic panel employs cells with different vertical heights (first cells with height H1, second cells with height H2) interspersed within the same panel. This local variation in cell geometry allows different frequency ranges to be targeted by different cell configurations, improving overall sound attenuation efficiency without requiring multiple separate panels.
Solution Approach 2:
The panel is segmented into multiple cell types (first cells and second cells) with distinct vertical heights, where each cell type is responsible for attenuating specific frequency ranges. This segmentation enables the panel to handle broadband noise more effectively than a uniform cell configuration.
2Reliability
If multiple cell types with different heights are used, then sound attenuation efficiency improves, but device complexity increases
Solution Approach 1:
Multiple cell types with different vertical heights are merged into a single monolithic panel structure. The first cells and second cells are interspersed within the same panel, combining their sound attenuation capabilities into one integrated component rather than using separate panels for different frequencies.
Solution Approach 2:
The acoustic panel is designed as a universal component that can attenuate multiple frequency ranges simultaneously through its interspersed first and second cells. This multi-functional design eliminates the need for multiple separate acoustic panels, reducing installation complexity despite the varied cell configurations.
3Reliability
If traditional acoustic panels are used, then sound attenuation is provided, but mass is excessive
Solution Approach 1:
The vertical height parameter of the cells is varied (first cells with height H1, second cells with height H2) to optimize sound attenuation for different frequencies. This parameter variation allows for more efficient sound attenuation with potentially less material, as each cell type is optimized for its specific frequency range rather than using a uniform over-designed configuration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The panel effectively attenuates multiple sound frequencies while minimizing mass by utilizing different cell heights and destructive interference, enhancing sound attenuation efficiency and reducing material usage.
Implementation Method 1
designed to attenuate sound waves through destructive interference
Data Source
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AI summary
An acoustic panel (20) for an aircraft includes a skin (32), a plurality of first cells (44) and a plurality of second cells (46) interspersed with the first cells (44). Each first cell (44) includes a first tube (48), a first endwall (50) and a first cavity (52). The first tube (48) projects vertically out from the skin (32) to a distal end (54) of the first tube (48). The first endwall (50) closes off the first cavity (52) at its distal end (54). The first cavity (52) extends vertically through the first tube (48) from the skin (32) to the first endwall (50). Each second cell (46) includes a second tube (66), a second endwall (68) and a second cavity (70). The second tube (66) projects vertically out from the skin (32) to a distal end (74) of the second tube (66). The second endwall (68) closes off the second cavity (70) at its distal end (74) and is offset from the first endwall (50). The second cavity (70) extends vertically through the second tube (66) from the skin (32) to the second endwall (68).