Variable-Width Composite Flange Stitching for Aircraft Stringers
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Solution Overview
Problem
Existing elongate aircraft structural components, such as stringers, face challenges in maintaining structural integrity and strength, particularly in regions with varying widths and those subjected to fastening, where material weakening can occur.
Innovation Solution
The development of an elongate aircraft structural component featuring a flange with varying widths, composed of layers of composite material, and reinforced with stitching that extends along a path with a component parallel to the width of the flange, enhancing strength and resistance to loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the flange width is increased to provide greater strength and resistance to loading, then the structural integrity is improved, but the weight and material consumption increase
Solution Approach 1:
The flange width is varied along its length, being wider at regions requiring greater strength (such as near the web junction) and narrower at regions where less strength is needed. This local variation in geometry provides optimized strength distribution without unnecessary weight addition throughout the entire component.
Solution Approach 2:
The flange is divided into multiple wide flange regions separated by narrow flange regions. This segmentation allows concentrated strength where needed while reducing material usage in intermediate sections, effectively managing the strength-weight trade-off.
2Strength
If stitching is added to interconnect composite material layers and increase strength, then the structural integrity is improved, but the manufacturing complexity increases
Solution Approach 1:
Stitching threads are introduced as an intermediary element to mechanically interconnect the composite material layers. These threads pass through multiple layers and are secured at intervals, creating a integrated structure that resists delamination and enhances overall strength without requiring complex bonding processes.
3Ease of manufacture
If chopped strand layers are used instead of conventional secondary unidirectional-fibre layers, then environmental friendliness and economy are improved, but the manufacturing precision may be affected
Solution Approach 1:
The invention changes the fibre form parameter from continuous unidirectional fibres to chopped strands. This parameter change enables the use of recycled materials and simplifies manufacturing processes while the stitching mechanism compensates for potential precision losses by mechanically binding the chopped strands in the desired orientation.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
Disclosed is an elongate aircraft structural component for an aircraft, the elongate aircraft structural component comprising a web and a flange, wherein the flange extends from the web, comprises layers of composite material, and has a length in a direction of a length of the elongate aircraft structural component, a width perpendicular to the length of the flange and a thickness smaller than, and perpendicular to, both the width and the length of the flange, wherein the width of the flange varies along the length of the flange, whereby the flange comprises a wide flange region and a narrow flange region, the narrow flange region having a smaller width than the wide flange region, and wherein the wide flange region comprises stitching interconnecting the layers of composite material, the stitching extending along a path in a direction with at least a component parallel to the width of the flange.