Aircraft Structural Panel Splice Joint for Low-Frequency Noise
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Solution Overview
Problem
Existing structural panels for attenuating sound generated by aircraft propulsion systems are not optimized for both structural stiffness and low-frequency sound attenuation, limiting their effectiveness in noise reduction.
Innovation Solution
A structural panel design featuring a multi-segment core structure with corrugated ribbons and porous septums, where the second core structure includes a plurality of resonance chambers divided by porous septums, and is attached to a first core structure at a splice joint, enhancing sound attenuation without increasing panel thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a structural panel uses conventional core structures, then manufacturing and assembly are simpler, but structural stiffness and low-frequency sound attenuation are insufficient
Solution Approach 1:
The core structure is divided into multiple segments including corrugated core segments, honeycomb core segments, and spacer segments. Each segment serves specific functions: corrugated segments provide structural stiffness, honeycomb segments provide sound attenuation, and spacer segments maintain spacing. This segmentation allows the panel to achieve both high structural stiffness and effective low-frequency sound attenuation without requiring a monolithic complex structure.
Solution Approach 2:
The structural panel employs a composite core structure combining different core materials (corrugated core, honeycomb core) with different skins (outer skin, inner skin). This composite construction leverages the complementary properties of each material: corrugated cores excel in stiffness, honeycomb cores excel in sound attenuation, and the combination achieves both performance requirements simultaneously.
2Object-affected harmful factors
If the panel thickness is increased to improve sound attenuation, then low-frequency noise reduction improves, but the panel becomes heavier and more difficult to install
Solution Approach 1:
Different core segments are strategically positioned at different locations within the panel thickness. Corrugated core segments are placed where structural stiffness is needed, while honeycomb core segments are placed where sound attenuation is prioritized. Spacer segments maintain optimal spacing between skins. This local differentiation allows effective low-frequency sound attenuation without uniformly increasing panel thickness and weight.
Solution Approach 2:
The panel design utilizes the thickness dimension efficiently by creating a multi-layered composite structure with skins spaced apart by core segments. This three-dimensional arrangement allows sound attenuation functionality to be achieved through the distributed volume of honeycomb cores rather than requiring excessive single-layer thickness, reducing overall panel weight while maintaining sound attenuation performance.
3Object-affected harmful factors
If multiple core segments are used to enhance sound attenuation, then low-frequency noise reduction improves, but manufacturing and assembly complexity increases
Solution Approach 1:
The core structure is divided into multiple independently manufacturable segments (corrugated core segments, honeycomb core segments, spacer segments) that can be manufactured separately using optimized processes for each segment type, then assembled into the complete panel structure.
Solution Approach 2:
Multiple core segments are combined with outer and inner skins to form an integrated composite panel structure. The segments are designed to work together synergistically, with corrugated cores providing stiffness, honeycomb cores providing sound attenuation, and spacers maintaining spacing, achieving enhanced low-frequency sound attenuation through their combined functionality.
4Strength
If core components project into the first core structure at splice joints, then structural stiffness and joint strength improve, but manufacturing precision requirements increase
Solution Approach 1:
The panel is divided into multiple core segments that are joined at splice joints. Each segment can be manufactured to standard dimensions with tolerances, and the segmentation allows for modular assembly. The corrugated core segments, honeycomb core segments, and spacer segments are designed as discrete units that simplify manufacturing while maintaining joint strength through their configured connections.
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 design effectively attenuates low-frequency noise by utilizing resonance chambers and improved mechanical interlocking at splice joints, providing enhanced structural stiffness and sound reduction capabilities.
Implementation Method 1
The second core structure may be configured with a plurality of resonance chambers. Each of the resonance chambers may extend laterally between the first wall and the second wall. Each of the resonance chambers may extend longitudinally between a respective adjacent pair of the baffles.
Implementation Method 2
The corrugated ribbon includes a plurality of baffles and a plurality of porous septums. The baffles and the porous septums are laterally between and connected to the first wall and the second wall.
Data Source
AI summary
A structural panel is provided that includes a first core structure and a second core structure. The second core structure includes a plurality of core components, which components includes a corrugated ribbon, a first wall and a second wall. The corrugated ribbon includes a plurality of baffles and a plurality of porous septums. The baffles and the porous septums are laterally between and connected to the first wall and the second wall. Each of the porous septums are longitudinally between a respective adjacent pair of the baffles. A first of the core components projects longitudinally into and/or along the first core structure at a splice joint between the first core structure and the second core structure.