Co-Cured Composite Tube Structure for Controlled Lightning Conductivity
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Solution Overview
Problem
Composite tube assemblies made of carbon fibers are electrically conductive, posing a challenge in aircraft applications where control of conductive paths during lightning strikes is necessary, and existing solutions like using resistive materials are not robust.
Innovation Solution
A composite tube design incorporating alternating layers of non-conductive and conductive materials, with the non-conductive section spanning less than 50% of the tube length and positioned to avoid the axial middle, enhancing structural integrity while allowing for controlled electrical pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If composite tubes made of carbon fibers are used, then weight is reduced and strength is improved, but electrical conductivity cannot be controlled during lightning strike events
Solution Approach 1:
The composite tube is segmented into multiple layers with alternating conductive and non-conductive sections. Each layer can be independently configured to provide either electrical conductivity or insulation, allowing the tube to be divided into functional segments that can control conductive paths while maintaining structural integrity.
Solution Approach 2:
Different sections of the composite tube have different electrical properties - some sections are conductive while others are non-conductive. This local differentiation of material properties allows the tube to provide structural strength throughout while controlling electrical conductivity in specific locations to manage lightning strike pathways.
2Reliability
If a non-conductive material insert is used to break conductive paths, then electrical resistance is improved, but structural strength and robustness are reduced
Solution Approach 1:
The tube is constructed as a composite structure with multiple layers combining conductive and non-conductive materials. This composite approach allows the non-conductive sections to provide electrical resistance while the overall multi-layer composite structure maintains structural robustness through the combined properties of all layers.
Solution Approach 2:
Each layer in the composite tube serves multiple functions - providing both structural support and controlling electrical conductivity. The non-conductive layers provide both structural integrity and electrical insulation, eliminating the need for separate insert components and maintaining overall structural robustness while achieving electrical resistance.
3Reliability
If the non-conductive section spans the entire tube length, then electrical resistance is maximized, but structural integrity and load-bearing capacity are compromised
Solution Approach 1:
The tube is segmented into alternating conductive and non-conductive layers rather than having a single continuous non-conductive section. This segmentation allows electrical resistance to be provided in specific layers while other layers maintain structural integrity and load-bearing capacity throughout the full tube length.
Solution Approach 2:
The electrical resistance property is distributed across multiple layers in the radial dimension rather than requiring a continuous non-conductive section along the axial dimension. This dimensional approach allows the tube to achieve electrical resistance through layering while maintaining structural strength through the overall composite construction.
Data Source
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AI summary
A composite tube includes a first end opposite a second end, a first axial section including a non-conductive material through its thickness, and a second axial section including a conductive material. A method for forming a composite tube includes laying a plurality of composite material layers over a mandrel forming a composite tube, and each of the plurality of layers includes a non-conductive section and a conductive section.