Polymeric Lightning Strike Coating for Lightweight CFRP Protection

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Solution Overview

Problem

Carbon fiber reinforced plastics (CFRPs) used in aerospace structures and wind turbine blades are vulnerable to lightning strikes due to their low electrical conductivity, leading to potential destruction from resistive heating, and existing metal mesh coatings cause galvanic corrosion and increased structural weight.

Innovation Solution

An all-polymeric protective material with an electrically conductive adhesive layer comprising MXene powders and conductive polymers, such as polyaniline, dispersed in an organic matrix, which provides electrical conductivity, corrosion resistance, and lightweight protection against lightning strikes and electromagnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal mesh coatings are used for lightning strike protection, then electrical conductivity is improved, but structural weight increases significantly

Engineering Contradiction:
Improvelightning strike protectionVSAvoidstructural weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the material parameter from metal to polymeric composite, achieving comparable electrical conductivity (≥1000 S/m) through a different material system that inherently has lower density and weight

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite material system consisting of conductive filler particles (carbon black, graphite, metal powders) dispersed in a polymeric matrix to achieve both electrical conductivity and lightweight properties simultaneously

Inventive Principle:
Principle #40Composite materials

2Reliability

If metal mesh coatings are used for lightning strike protection, then electrical conductivity is improved, but galvanic corrosion occurs at the metal/carbon composite interface

Engineering Contradiction:
Improvelightning strike protectionVSAvoidgalvanic corrosion
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the metal component from the protective coating system, eliminating the source of galvanic corrosion while maintaining lightning strike protection through polymeric composite materials with embedded conductive fillers

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The polymeric matrix acts as an intermediary between the CFRP structure and the conductive filler particles, providing electrical conductivity without creating galvanic corrosion conditions that occur with direct metal-to-carbon contact

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If metal mesh foils are used for lightning strike protection, then electrical conductivity is improved, but additional materials and bonding processes are required

Engineering Contradiction:
Improvelightning strike protectionVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the lightning strike protection function with the existing CFRP manufacturing process by incorporating conductive fillers directly into the polymeric matrix that bonds with the CFRP structure, eliminating the need for separate metal mesh foils and bonding operations

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The polymeric composite coating provides multiple functions simultaneously: lightning strike protection through electrical conductivity, structural bonding to CFRP, and potential corrosion resistance, eliminating the need for separate specialized components

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 solution effectively mitigates lightning strike damage, reduces weight compared to metal-mesh systems, and enhances structural integrity by providing a conductive path for electrical current, while also acting as a Faraday cage and offering high thermal stability and low flammability.

Implementation Method 1

If the structure does not possess enough electrical conductivity to dissipate the incident current, these structures can be destroyed due to the extreme amount of heat produced by resistive heating

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The protective material not only withstands lightning strikes, but also functions as shielding against electromagnetic interference

Methodology Applied
Scientific EffectFaraday cage effect: Faraday Cage

Data Source

PatentUS11873382B23D printable polymeric lightning strike protection system for fiber reinforced composites
Publication Date: 2024.01.16 UT BATTELLE LLC

AI summary

The current embodiments include all-polymeric protective material for mitigating lightning strike damage. The protective material includes a hybrid matrix comprising PANI and MXene dispersed within a thermosetting epoxy resin. This hybrid matrix can be painted, printed, or applied as a conductive polymeric layer to a FRCP structure, for example an aircraft fuselage, wing, empennage, control surface (aileron, flap, slats, rudder, elevator) or a wind turbine blade. The protective material not only withstands lightning strikes, but also functions as shielding against electromagnetic interference and is corrosion-resistant and lightweight.