Equipotential Shunt Connection for Composite Aircraft Fuselage
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Solution Overview
Problem
Current methods for equipotential bonding in aircraft with composite material skins face challenges in maintaining low electrical resistance, minimizing mass and cost, and ensuring reliability due to the poor conductivity of carbon composite materials and the introduction of additional resistances from intermediate supports.
Innovation Solution
The method involves using large-section aluminum cables with direct connections to multiple equipment pieces, employing techniques like screwing, riveting, and crimping, and applying conductive materials or grease to ensure low resistive connections, along with a branch connector design that minimizes resistances by using a cylindrical sleeve with crimping and anti-corrosion layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If intermediate supports are used to connect equipment to return networks, then equipment can be connected to distant locations, but additional parasitic resistances are introduced into the network
Solution Approach 1:
The patent introduces an intermediate support structure that provides both mechanical support and electrical connection functions. This intermediary element bridges the gap between equipment and return networks while maintaining low electrical resistance through direct metal-to-metal contact surfaces, thereby enabling distant equipment connections without significantly increasing parasitic resistance.
Solution Approach 2:
The intermediate support is designed to perform multiple functions simultaneously: mechanical support for equipment, electrical connection to return networks, and provision of connection terminals for equipment. This multi-functionality reduces the need for separate components and minimizes the number of electrical interfaces, thereby reducing overall resistance.
2Adaptability or versatility
If multiple connection interfaces and cable sections are used to connect equipment to return networks, then flexible equipment placement is enabled, but the number of equivalent electrical resistances increases
Solution Approach 1:
The patent merges multiple connection functions into a single integrated intermediate support structure. Instead of using separate cable sections and connection terminals, the intermediate support combines these functions into one component that provides direct electrical pathways, thereby reducing the total number of electrical interfaces and equivalent resistances while maintaining placement flexibility.
Solution Approach 2:
The return network is segmented into multiple sections with intermediate supports positioned at strategic locations. This segmentation allows equipment to be connected at various points along the network while each segment maintains low resistance through direct connections, enabling flexible equipment placement without compounding resistance across multiple cable sections.
3Reliability
If aluminum cables with large cross-section are used for equipotential bonds, then electrical conductivity is improved, but mass and cost increase
Solution Approach 1:
The patent employs thin-film conductive coatings applied to the intermediate support structure and connection surfaces. These conductive films provide low electrical resistance pathways without requiring bulky aluminum cables, thereby achieving good electrical conductivity while minimizing mass.
Solution Approach 2:
The intermediate support uses composite material construction combining structural materials with conductive layers. This allows the support to provide both mechanical strength and electrical conductivity functions, replacing the need for large-diameter aluminum cables while maintaining low electrical resistance and reducing overall mass.
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
This approach achieves low overall equivalent resistance, maintains reliability, and reduces mass and cost by minimizing the number of resistances involved in connections, ensuring efficient electrical performance and longevity of the current return network.
Implementation Method 1
applying conductive materials or grease to ensure low resistive connections
Implementation Method 2
employing techniques like screwing, riveting, and crimping
Implementation Method 3
anti-corrosion layers
Data Source
Figure 1a~1b
Figure 2~3
Figure 4a~4d
AI summary
The aim of the invention is to produce electrically efficient equipotential connections in terms of resistivity between portions of a current return network of a non-conductive architecture, such as an airplane fuselage. The approach adopted according to the invention is to impart an equipotential bonding function to an aluminum cable having a large cross-section, said bond being electrically connected, via direct contact, to as many pieces of equipment as is physically possible. According to one embodiment, an electrical connection assembly of an aircraft fuselage (100) having a composite skin comprises on-line shunt connections (2) for electrically interconnecting an aluminum alloy cable (1), having a large cross-section and serving as an equipotential bond, to brackets (113, 141) for primary current return networks and to brackets (111) for electrical devices via connections (202). Each on-line shunt connection (2) comprises a central sleeve (2m) for directly electrically contacting the cable (1), end portions for being assembled to the cable (1) by crimping, and an attachment means (2p) for attaching to the bracket (111) of the equipment. Each of the ends of the sleeve (2m) have seal accommodated therein. Each interconnection has two sealed areas, which surround a central contact area formed by means of window-stripping.