Noise Reduced End Rib Assembly for Aircraft High-Lift Devices
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Solution Overview
Problem
High-lift devices on aircraft, particularly end ribs, contribute significantly to noise emissions during descent and approach, leading to regulatory issues and additional fees, with existing solutions failing to effectively reduce high acoustic frequencies.
Innovation Solution
An end rib assembly for high-lift devices featuring a noise-reducing portion with metal-foam and a guiding portion that directs airflow towards the noise-reducing portion, combined with a bearing arrangement and attachment system to minimize noise generation between the wing and high-lift device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional end rib assembly is used, then the structure is simple and easy to manufacture, but noise emissions from airflow around the end rib are high
Solution Approach 1:
The end rib assembly is divided into distinct functional portions: a guiding portion that directs airflow and a noise-reducing portion that absorbs sound. This segmentation allows each portion to be optimized for its specific function while maintaining overall structural integrity.
Solution Approach 2:
The guiding portion acts as an intermediary element that channels airflow toward the noise-reducing portion. This intermediary structure enables the airflow to be directed through or over the noise-reducing material, maximizing noise reduction effectiveness.
2Object-affected harmful factors
If the guiding portion is shaped to direct airflow towards the noise-reducing portion, then noise reduction is improved, but manufacturing precision requirements increase
Solution Approach 1:
The guiding portion features localized geometric characteristics, particularly at its leading edge, that are specifically designed to direct airflow. Rather than requiring precision throughout the entire structure, only specific local areas need enhanced manufacturing precision to achieve the airflow directing function.
3Object-affected harmful factors
If noise-reducing material is added to the end rib assembly, then noise emissions are reduced, but weight of the assembly increases
Solution Approach 1:
The noise-reducing portion utilizes porous or foam-like materials that provide effective noise absorption while maintaining low density. These materials reduce high acoustic frequencies without significantly increasing the weight of the end rib assembly.
Solution Approach 2:
The noise-reducing material is applied locally to the end rib assembly where it is most needed for noise reduction, rather than throughout the entire structure. This localized application minimizes weight increase while achieving the noise reduction objective.
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
Substantially reduces noise emissions across the relevant frequency spectrum, allowing for later landing times and potential cost savings by meeting noise regulations, while maintaining aerodynamic efficiency and usability on larger aircraft.
Implementation Method 1
a noise-reducing portion (20) configured to reduce noise caused by an airflow around the end rib assembly
Implementation Method 2
a guiding portion (18) configured for guiding the end rib assembly along a predetermined path, when the high-lift device is moved between a retracted position and an extended position, wherein the guiding portion is formed in such a way that an airflow impinging on the guiding portion is partly guided towards the noise-reducing portion
Data Source
AI summary
An end rib assembly for a high-lift device of an aircraft to reduce the noise caused by the transition between the wing and a high-lift device as well as the noise caused by the lateral side edge of the end rib assembly. An end rib assembly includes a noise-reducing portion configured to reduce noise caused by an airflow around the end rib assembly, and a guiding portion configured for guiding the end rib assembly along a pre-determined path when the high-lift device is moved between a retracted position and an extended position, wherein the guiding portion is formed such that an airflow impinging on the guiding portion is partly guided towards the noise-reducing portion.