Trailing Edge Joining Element for Aerodynamic Profiles
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Solution Overview
Problem
Current joining methods for trailing edges of aerodynamic profiles, such as aircraft wings, face limitations in achieving a continuous aerodynamic profile due to minimum core thickness requirements, leading to adverse effects like 'knife edge' and increased weight, and hinder the use of solid rivets, which can cause delamination and complicate tool access.
Innovation Solution
A joining element with an elongated laminar skin featuring a half-arrowhead profile, allowing insertion between converging skins to maintain a flush surface, enabling the use of solid rivets and reducing material usage, while allowing for a greater variety of joining elements and tools, and filled gaps with sealant for aerodynamic continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sandwich composite skins with minimum core thickness are used, then structural strength is improved, but aerodynamic profile continuity deteriorates due to slope changes at the trailing edge
Solution Approach 1:
A filler element is introduced as an intermediary component between the upper and lower sandwich composite skins at the trailing edge. This filler element has a variable thickness profile that tapers to match the converging skins, providing structural support while maintaining aerodynamic profile continuity by filling the gap created by the minimum core thickness requirement
Solution Approach 2:
The filler element's thickness parameter varies along its length, being thickest at the root and tapering to zero at the trailing edge. This parameter change allows the filler to provide structural support where needed while becoming invisible aerodynamically at the trailing edge, resolving the contradiction between structural requirements and aerodynamic profile
2Shape
If metal clip-type sheets with paste filling are used, then aerodynamic profile continuity is improved, but reliability deteriorates due to paste cracking and detachment
Solution Approach 1:
The problematic paste material is completely removed from the trailing edge structure. Instead, a solid filler element with matching aerodynamic profile is used, which provides both structural support and aerodynamic continuity without the adhesion and cracking issues of paste-based solutions
Solution Approach 2:
The filler element is made from composite materials that are compatible with the sandwich composite skins, providing a reliable, integrated structure that maintains aerodynamic profile without relying on paste adhesion. The composite filler element bonds reliably with the skins while maintaining the desired aerodynamic shape
3Ease of manufacture
If protruding rivets are used for joining, then ease of manufacture is improved, but aerodynamic profile continuity deteriorates and inspection accessibility is reduced
Solution Approach 1:
The filler element incorporates localized joining features such as recesses or engagement structures at specific locations where rivets or other joining elements can be hidden within the filler's thickness. This allows protruding rivets for ease of manufacture while maintaining aerodynamic profile continuity by concealing the rivet heads within the filler element's volume
4Reliability
If solid rivets are used for joining, then reliability is improved, but device complexity increases due to delamination risk and tool access limitations
Solution Approach 1:
The filler element is designed with segmented or modular features that facilitate tool access from both sides of the trailing edge. The filler may include access holes, recesses, or removable sections that allow installation tools to reach solid rivets without requiring complex external tool access, reducing installation complexity while maintaining the reliability of solid rivet joining
Data Source
Figure 1~2
Figure 3~4
AI summary
Joining element for trailing edges of aerodynamic profiles, insertable at the edge of structures with an aerodynamic profile made up of an upper skin (1) and a lower skin (2) being converging. The joining element is made up of an elongated laminar body (3), with an upper face (4) that can be orientated towards an internal face of the upper skin (1); a lower face (5) orientable towards an internal face of the lower skin (2); an outer longitudinal edge (6); an inner longitudinal edge (7); and two side profiles (8). On each of its faces (4,5) it comprises a plurality of projections (9,10,14) that give its lateral profiles (8) a geometry of a half arrowhead so that the converging skins (1,2) remain at the same level as the outer surface of the invention after assembly, flush, and any gaps are filled with sealant, forming continuous and smooth outer surfaces.