Conductive Composite Particles for Aircraft Lightning Protection

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Solution Overview

Problem

Aircraft composite materials face challenges in achieving high electrical conductivity in the z-direction due to the dielectric nature of resin matrices, which affects lightning strike protection and electromagnetic shielding, while existing solutions either compromise mechanical performance or are difficult to process.

Innovation Solution

Incorporating micron-sized conductive composite particles with a conductive component and a polymeric component that undergoes phase transition during curing, creating electrical bridges between fibre layers and enhancing both conductivity and mechanical properties like impact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conductive particles or polymers are incorporated in the resin matrix to improve electrical conductivity, then z-direction conductivity is improved, but mechanical performance deteriorates

Engineering Contradiction:
Improveelectrical conductivityVSAvoidmechanical performance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The conductive element is segmented into discrete micron-sized particles rather than continuous forms. These particles are distributed throughout the resin matrix, providing conductivity pathways while minimizing disruption to the mechanical structure compared to continuous conductive layers or high concentrations of conductive material.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Conductivity is localized to specific regions where conductive particles are distributed, rather than requiring the entire resin matrix to be conductive. This allows the bulk material to maintain its mechanical properties while achieving sufficient conductivity through strategic particle placement and aggregation.

Inventive Principle:
Principle #3Local quality

2Reliability

If high concentration of conductive material is used to achieve required conductivity, then electrical conductivity is improved, but processing difficulty increases

Engineering Contradiction:
Improveelectrical conductivityVSAvoidprocessing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The conductive resin composition utilizes specific parameter ranges including conductive material content of 0.1-10 wt%, particle size distribution, and viscosity control to achieve optimal balance between conductivity and processability. These parameter optimizations allow standard composite manufacturing processes to be used without requiring excessive conductive material additions.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conductive particles are added to improve conductivity, then z-direction conductivity is improved, but delamination resistance deteriorates

Engineering Contradiction:
Improveelectrical conductivityVSAvoiddelamination resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention creates a composite system where conductive particles are embedded within a resin matrix that is itself impregnated into fiber layers. This multi-level composite structure (conductive particles in resin, resin in fibers, fiber layers stacked) provides both conductivity pathways and mechanical bonding, with the resin serving dual functions of electrical insulation/binding and structural reinforcement.

Inventive Principle:
Principle #40Composite materials

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 significantly improves z-direction conductivity and delamination strength, reducing the risk of catastrophic damage from lightning strikes and enhancing electromagnetic performance while maintaining mechanical integrity.

Implementation Method 1

The polymeric component of the electrically conductive composite particle is initially in a solid phase and substantially insoluble in the curable resin matrix prior to curing of the resin matrix, but it is able to undergo at least partial phase transition to a fluid phase during the cure cycle of the resin matrix

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 2

the individual fibers of the bundles are constructed of a dielectric material and at least some of the individual fibers in at least some of the bundles have an electrically conductive surface coating extending over substantially the full length of such fibers

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2838702B1Composite materials
Publication Date: 2020.06.10 CYTEC TECHNOLOGY CORP
  • EP2838702B1 patent drawingFigure 1~2
  • EP2838702B1 patent drawingFigure 3A~3B
  • EP2838702B1 patent drawingFigure 4~5B

AI summary

A composite material that includes a layer of reinforcing fibres impregnated with a curable resin matrix and a plurality of electrically conductive composite particles positioned adjacent or in proximity to the reinforcing fibres. Each of the electrically conductive composite particles is composed of a conductive component and a polymeric component, wherein the polymeric component includes one or more polymers that are initially in a solid phase and are substantially insoluble in the curable resin, but is able to undergo at least partial phase transition to a fluid phase during a curing cycle of the composite material.