Segmented Composite Tube Joint With Wedge Load Transfer
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Solution Overview
Problem
Conventional methods for attaching fiber-reinforced polymer-matrix composite tubes to metallic parts in aircraft actuators result in reduced structural performance due to stress concentrations and inadequate load transfer, particularly when composite fibers are oriented parallel to the tube's longitudinal axis.
Innovation Solution
A composite joint assembly featuring a composite tube with angled segments separated by slits, flared radially, and a support wedge that engages the end portions to enhance load transfer, eliminating the need for threading or drilling, and allowing for improved stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional attachment methods are used to join composite tubes to metallic parts, then the joint can be manufactured with existing techniques, but the structural performance is reduced due to stress concentrations and inadequate load transfer
Solution Approach 1:
The end portion of the composite tube is segmented into multiple circumferential segments separated by slits. This segmentation allows the segments to be independently deformed and positioned at angles relative to the longitudinal axis, enabling effective load transfer to the metallic part while distributing stress concentrations. The segmented structure maintains structural performance by allowing each segment to engage with the metallic component separately.
Solution Approach 2:
The composite tube structure is modified locally at the end portion where segments are created and angled relative to the longitudinal axis. This local modification enables effective load transfer and stress distribution at the joint interface without changing the overall tube structure. The angled segments provide enhanced mechanical interlocking with the metallic part while maintaining the integrity of the composite material throughout.
2Force
If composite fibers are oriented parallel to the longitudinal axis for optimal axial load handling, then the tube can handle significant axial loads, but conventional attachment methods cannot effectively transfer loads from the composite elements to metallic parts
Solution Approach 1:
The end portion is divided into segments that can be independently angled relative to the longitudinal axis. This segmentation enables the segments to mechanically engage with the metallic part, creating effective load transfer pathways from the composite tube to the metallic component while maintaining the parallel fiber orientation for optimal axial load handling in the main body of the tube.
Solution Approach 2:
The segments are angled at an angle relative to the longitudinal axis, introducing a dimensional change from the parallel fiber orientation. This angular orientation at the end portion creates mechanical interlocking with the metallic part, enabling effective load transfer in addition to the axial load capacity provided by the parallel fiber orientation in the tube body.
3Strength
If the composite tube end portion is modified with angled segments to improve load transfer, then stress distribution is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The end portion is segmented into multiple circumferential segments separated by slits, which simplifies the achievement of angled configurations. Each segment can be independently positioned and secured to the metallic part, distributing stress concentrations effectively. The segmentation approach reduces the complexity of creating uniform angular deviations across the entire end portion by treating it as discrete, manageable segments.
Solution Approach 2:
The slits are pre-formed in the composite tube end portion before the final assembly with the metallic part. This preliminary action allows the segments to be easily deformed into the desired angled positions and secured to the metallic component. The pre-formed slits simplify the manufacturing process by enabling straightforward segment separation and positioning without requiring complex forming operations during final assembly.
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
The composite tube (100) may include a body having a longitudinal centerline axis and at least one end portion. The at least one end portion may include a plurality of segments (122, 222, 422, 522, 622) that are angled relative to the longitudinal centerline axis and are circumferentially separated from each other by a plurality of slits. The composite tube (100) may be implemented in a joint assembly that includes a support wedge. The support wedge may at least partially engage at least one of a radially inward surface of the at least one end portion and a radially outward surface of the at least one end portion.