Multi-Tube Aircraft Wing Joint for Lightweight Composite Strength
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Solution Overview
Problem
The challenge in designing a double bubble fuselage is creating a strong and lightweight three-way joint between adjacent bubbles and the central portion, while minimizing the risk of delamination in composite structures.
Innovation Solution
A composite attachment coupler with a Y-shaped design, featuring warp tows in the longitudinal direction and cross-woven weft tows, which are wound around a central cluster of tows to enhance strength, is used to join adjacent tube structures and a central panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional three-way joint structure is used to join adjacent bubbles and central portion, then the structural strength is insufficient, but the weight increases and delamination risk increases
Solution Approach 1:
The patent employs composite material construction for the tubular structure, utilizing multiple layers of fiber reinforcement (such as carbon fiber, glass fiber, or aramid fiber) embedded in a polymer matrix. This composite approach enables the joint to achieve exceptional strength-to-weight ratio, resolving the contradiction between joint strength and weight by providing a material system that inherently combines both properties.
Solution Approach 2:
The three-way joint is segmented into multiple functional components: a central hub structure, radial arms connecting to each bubble, and integrated reinforcement layers. This segmentation allows each component to be optimized for its specific load path, with fibers oriented to match principal stress directions, achieving high strength without excessive weight.
2Strength
If a traditional three-way joint structure is used to join adjacent bubbles and central portion, then the structural strength is insufficient, but the delamination risk increases
Solution Approach 1:
The patent changes the material parameters and structural geometry parameters of the joint to optimize performance. Fiber orientation angles are specifically selected to match principal stress trajectories, layer thicknesses are optimized for load distribution, and the hub geometry is tailored to distribute stresses uniformly. These parameter changes simultaneously increase joint strength and prevent delamination by ensuring stress remains within safe limits.
Solution Approach 2:
The composite structure incorporates redundant load paths and stress-distributing geometry that preemptively cushion against stress concentrations that could lead to delamination. The multi-layered construction with properly oriented fibers creates a barrier that prevents crack propagation and delamination before they can initiate, providing built-in protection against failure modes.
3Weight of stationary object
If the joint structure is made lighter to reduce weight, then the weight decreases, but the structural strength decreases
Solution Approach 1:
The joint structure implements local quality optimization by varying fiber orientation, layer thickness, and material composition at different locations within the joint. High-strength fiber orientations are concentrated in regions of high stress, while lighter constructions are used in low-stress areas. This localized optimization achieves minimum weight while maintaining required strength throughout the entire joint structure.
Solution Approach 2:
The patent transitions from two-dimensional planar joint designs to three-dimensional spatial optimization. The hub structure and radial arms are configured in three-dimensional space to optimize load paths, with fibers arranged in multiple orientations across different layers and angles. This dimensional approach allows weight reduction through optimized material distribution while maintaining strength through three-dimensional stress distribution.
Data Source
AI summary
An aircraft wing with tube sections residing therein which may be used to house passengers, fuel, cargo, and other items, and which may be an asymmetric oblique wing aircraft. A joining structure adapted to join adjacent tube structures together while providing high strength with low weight. The joining structure may be of composite materials, and may include warp tows in the longitudinal direction of the tubes and have weft tows cross-woven into a fabric, which may be a carbon fiber. The joining structure may be Y-shaped and adapted to join three composite sheets together. The weft tows may also be wound around a central cluster of tows, or tows, which may provide extra strength. The tubes may be pressurized in use, such as in an aircraft fuselage.