Composite Structural Element with Integrated Metallic Conductive Layer for Current Return

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Solution Overview

Problem

Modern aircraft with composite structures face challenges in current return networks due to the lack of suitable conductivity, leading to the need for additional weighty dedicated conductive cables, and existing lightning protection systems require connection to a current return network for proper grounding and current handling.

Innovation Solution

Integration of metallic conductive layers within composite structural elements, such as expanded metal foils or conductive inks, to provide a continuous conductive path for current return, reducing weight and improving conductivity while matching the coefficient of thermal expansion with the composite materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated conductive cables are used in composite structures, then current return requirements are met, but structural weight increases significantly

Engineering Contradiction:

Improvecurrent return capabilityVSAvoidstructural weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines the structural function and current return function into a single integrated component. The composite structural element incorporates conductive layers, meshes, or particles directly within the composite material matrix, eliminating the need for separate dedicated conductive cables. This merging reduces weight while maintaining both structural integrity and electrical conductivity for current return paths.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite materials by integrating conductive phases (conductive layers, meshes, or particles) within the composite structural element matrix. This creates a multi-functional material that provides both mechanical structural support and electrical conductivity, resolving the contradiction between needing current return capability and minimizing structural weight.

Inventive Principle:

Principle #40Composite materials

2Weight of moving object

If composite materials are used for major structural elements, then weight is reduced, but conductivity for current return is insufficient

Engineering Contradiction:

Improvestructural weightVSAvoidconductivity

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent creates a multi-phase composite material system where conductive phases (layers, meshes, or particles) are embedded within the composite structural matrix. This composite approach maintains the weight advantages of composite materials while introducing conductive pathways to restore electrical conductivity for current return requirements.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by concentrating conductive materials at specific locations and orientations within the composite structure where current return is needed. The conductive layers, meshes, or particles are strategically positioned to create effective current pathways while minimizing overall material usage and maintaining structural efficiency.

Inventive Principle:

Principle #3Local quality

3Reliability

If conductive foils are integrated into composite skins, then lightning protection is improved, but connection to current return network becomes complex

Engineering Contradiction:

Improvelightning protectionVSAvoidconnection complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the lightning protection function and current return network connection into a single integrated system. The conductive layers within the composite structural elements serve dual purposes: providing lightning strike protection and simultaneously forming the current return pathways. This eliminates the need for separate connection systems and reduces overall complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The conductive layers integrated into the composite structural elements perform multiple functions simultaneously: they provide lightning protection, establish current return paths, and enable grounding. This multi-functionality reduces the number of separate components and connections needed, simplifying the overall system while improving reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution reduces the weight and inductance of current return systems, lowers self-induced voltage, and effectively grounds aircraft systems by integrating conductive layers within composite structures, enhancing the efficiency of current handling and lightning protection without the need for dedicated cables.

Implementation Method 1

at least one metallic conductive layer is integrated with and extends the length of the web. At least one metallic layer is configured to electrically bond to an aircraft system and provide a ground path

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3284680B1Integrated current return network in composite structures

Publication Date: 2020.03.18 THE BOEING CO

Figure 1
Figure 2A~2C
Figure 3~4B

AI summary

An aircraft component incorporated in a current return network (CRN) employs a composite structural element having a web. At least one flange is connected to the web. At least one metallic conductive layer is integrated with and extends the length of the web. The at least one metallic layer is configured to electrically bond to an aircraft system and provide a ground path.