Hybrid Composite-Metal Lobe Joint for Axial Load Transfer
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Solution Overview
Problem
Conventional metallic aircraft landing gear components are heavy and costly, and there is a challenge in implementing strong joints for load transfer from composite elements to metallic parts, particularly in handling axial and bending loads.
Innovation Solution
A composite tube joint design featuring a protuberant surface with a convex geometry that mechanically locks onto a metallic attachment feature, comprising separate lobes and flanges to mitigate movement and distribute loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite materials are used to substitute metallic materials in aircraft landing gear components, then weight and cost are reduced, but the challenge of implementing strong joints for load transfer from composite elements to metallic parts increases
Solution Approach 1:
The attachment feature is divided into multiple lobes (typically three lobes at 120 degrees apart) that are embedded within the composite tube. This segmentation allows the load to be distributed across multiple discrete contact points rather than a single continuous interface, improving both the mechanical interlocking and load transfer efficiency while maintaining the weight reduction benefits of composite materials.
Solution Approach 2:
The lobes are nested within the composite tube structure, with the protuberant surfaces of the lobes positioned inside the tube bore. This nesting arrangement creates a mechanical interlock where the lobes are surrounded by the composite material, providing strong anchoring while allowing the composite tube to maintain its structural integrity and weight advantages.
2Ease of manufacture
If a simple cylindrical interface is used between composite tube and metallic attachment feature, then manufacturing is easier, but the ability to mitigate axial and bending loads is insufficient
Solution Approach 1:
The attachment feature incorporates lobes with protuberant surfaces that have curved or rounded geometries rather than sharp edges. This curvature distributes stress more evenly during load transfer, reducing stress concentrations that would occur with sharp corners, and improving both the bending and axial load capacity while remaining compatible with composite manufacturing processes.
Solution Approach 2:
The lobes are positioned at specific locations around the composite tube circumference (typically spaced at 120 degrees) to provide localized load transfer zones. This local quality approach concentrates the load-bearing function at specific strategic points rather than requiring a uniformly complex interface throughout the entire circumference, balancing manufacturing ease with load transfer strength.
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 composite tube joint reduces weight and cost while maintaining structural integrity by effectively transferring axial and bending loads between composite and metallic components, preventing slipping and ensuring secure attachment.
Implementation Method 1
the protuberant surface mechanically locks the end onto the attachment feature
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3~5
AI summary
A composite tube joint may comprise an end of a composite tube (110), an attachment feature (120) comprising a first portion (122) disposed within the end and a second portion (124) extending from the end, wherein the first portion (122) comprises a protuberant surface (210), and the protuberant surface (210) mitigates movement of the attachment feature (120) relative to the composite tube (110).