Co-Cured Composite Tube Structure for Lightning Path Isolation
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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
Designing composite tubes with alternating layers of non-conductive and conductive materials, such as fiberglass and carbon fibers, to create a section that is electrically non-conductive, ensuring the conductive paths are controlled without compromising structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If composite tubes made of carbon fibers are used, then strength and weight properties are 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 material sections along its axial length. This segmentation allows different portions of the tube to have different electrical conductivity properties, enabling control of conductive paths while maintaining structural integrity.
Solution Approach 2:
Different sections of the composite tube have different electrical conductivity properties. Specifically, non-conductive material sections are positioned at locations where electrical path control is desired, while conductive sections are positioned where structural strength is prioritized. This local differentiation resolves the contradiction between overall strength and localized electrical conductivity control.
2Reliability
If resistive engineering material is used to break conductive paths, then electrical conductivity control is improved, but structural robustness is compromised
Solution Approach 1:
The tube uses composite material construction with alternating sections of conductive carbon fiber materials and non-conductive materials integrated within the same structure. This composite approach allows the tube to maintain high structural robustness from the carbon fiber sections while achieving electrical conductivity control through the non-conductive sections, eliminating the need to choose between strength and electrical control.
3Reliability
If non-conductive material sections are added to control electrical paths, then electrical conductivity control is improved, but device complexity increases
Solution Approach 1:
The electrical conductivity control function is merged into the tube structure itself by integrating non-conductive material sections directly into the composite tube layers. This eliminates the need for separate external components or attachments, as the tube wall itself provides both structural support and electrical path control through its multi-layered construction with alternating conductive and non-conductive sections.
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 tubes achieve a compressive strength of at least 2,000 lbf and tensile strength of at least 3,000 lbf while effectively managing electrical conductivity, making them suitable for aircraft applications.
Implementation Method 1
The carbon fibers which make up the structural material of the composite tubes are electrically conductive. As such, the composite tube assemblies are not electrically resistive and thus, cannot be used in aircraft locations where control of conductive paths through the structure is desired.
Data Source
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.