Hybrid Lightning Strike Protection Layer for Aircraft Structures

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Solution Overview

Problem

Current lightning strike protection systems for aircraft and spacecraft, such as those using expanded metallic copper foils, face challenges in efficiently dissipating lightning strike energy and providing adequate electromagnetic shielding while maintaining structural integrity and minimizing weight and thermal damage.

Innovation Solution

A hybrid lightning strike protection layer is created by combining a metallic layer with a carbon nanotube mat, which enhances electrical conductivity and thermal stability, reducing Joule heat generation and mechanical damage, and can be integrated into fiber-reinforced polymer structures, potentially replacing traditional surfacing films.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If expanded metallic copper foils are used for lightning strike protection, then lightning strike energy dissipation is improved, but weight increases and thermal damage occurs

Engineering Contradiction:

Improvelightning strike protectionVSAvoidprotection layer weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining carbon nanotubes with traditional metallic copper foils to create a hybrid protection layer. This composite structure leverages the high electrical conductivity of copper for lightning strike protection while the carbon nanotubes provide enhanced electrical conductivity and reduced weight, thereby resolving the contradiction between protection effectiveness and weight reduction

Inventive Principle:

Principle #40Composite materials

2Reliability

If expanded metallic copper foils are used for lightning strike protection, then lightning strike energy dissipation is improved, but Joule heat generation increases causing thermal damage

Engineering Contradiction:

Improvelightning strike protectionVSAvoidJoule heat temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The hybrid composite structure combines copper foils with carbon nanotubes, where the carbon nanotubes provide alternative conduction paths that reduce Joule heat generation. The carbon nanotubes' superior electrical conductivity and thermal properties allow for more efficient energy dissipation with reduced thermal damage, resolving the contradiction between protection effectiveness and thermal damage

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the electrical conductivity parameter by introducing carbon nanotubes into the copper foil structure. This parameter change enables more efficient current distribution and reduces resistive heating, thereby reducing Joule heat generation while maintaining lightning strike protection effectiveness

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If traditional surfacing films are used, then electromagnetic shielding is provided, but weight increases and structural integrity is compromised

Engineering Contradiction:

Improveelectromagnetic shieldingVSAvoidstructural integrity

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent uses a hybrid composite of carbon nanotubes and metallic copper foils that provides both electromagnetic shielding and structural reinforcement. The carbon nanotubes form a conductive network for electromagnetic shielding while simultaneously strengthening the composite structure, thereby resolving the contradiction between electromagnetic shielding and structural integrity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The carbon nanotube-copper foil composite serves multiple functions simultaneously: it provides lightning strike protection, electromagnetic shielding, and structural reinforcement. This multi-functionality eliminates the need for separate protective layers, thereby maintaining structural integrity while providing comprehensive protection

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

The hybrid layer provides effective lightning strike protection with reduced weight, lower electrical resistance, and improved thermal stability, minimizing damage and maintenance costs, while maintaining structural integrity and allowing for existing manufacturing processes to be used.

Implementation Method 1

the electrical resistivity of expanded copper foils is significantly larger than that of CFRP/GFRP laminate, the lightning current flows almost completely within the lightning strike protection layer

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

reducing Joule heat generation and mechanical damage

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11969983B2Structural component

Publication Date: 2024.04.30 AIRBUS DEFENCE & SPACE GMBH

AI summary

A structural component for an aircraft, spacecraft or rocket has a ply of fiber reinforced polymer, a first carbon nanotube mat; and a metallic layer, wherein the carbon nanotube mat and the metallic layer are arranged on the ply of fiber reinforced polymer to form a hybrid lightning strike protection layer. A component for manufacturing such a structural component, a method for manufacturing a component of this type, a method for manufacturing a structural component and an aircraft or spacecraft with such a structural component are described.