3D Woven Conductive Composite for Lightning Strike Protection

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Solution Overview

Problem

Existing composite structures face challenges in dissipating electrical current along the Z-axis during a lightning strike, leading to potential damage from localized current concentration, as conventional methods like conductive coatings or metallic meshes are ineffective in the Z-direction and can cause micro-cracking or resin pooling.

Innovation Solution

A three-dimensionally woven electrically conductive composite structure with carbon fiber layers and conductive filaments woven along the X, Y, and Z axes, allowing for continuous electrical current dissipation and preventing localized current concentration through electron tunneling or capacitive coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conductive coatings or metallic meshes are applied to the outer surface, then electrical current dissipation along the X and Y axes is improved, but electrical current dissipation in the Z direction remains ineffective

Engineering Contradiction:
Improveelectrical current dissipationVSAvoidthree-dimensional conductivity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from two-dimensional surface conductivity (X-Y plane) to three-dimensional volumetric conductivity by weaving conductive filaments through the thickness of the composite structure. This dimensional extension enables current dissipation in all three spatial directions, resolving the limitation of conventional surface treatments that cannot effectively dissipate current in the Z direction.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent creates a composite structure combining non-conductive carbon fiber layers with conductive filaments woven throughout. This composite approach integrates both the structural benefits of carbon fiber and the electrical conductivity of the filament material, achieving three-dimensional current dissipation while maintaining the integrity of the composite structure.

Inventive Principle:
Principle #40Composite materials

2Reliability

If metallic wire is continuously woven through the material, then electrical conductivity is improved, but thermal expansion differences cause micro-cracking

Engineering Contradiction:
Improveelectrical conductivityVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies conductive filaments selectively through the thickness of the composite structure rather than continuously throughout. This localized application provides necessary electrical conductivity while minimizing the total amount of conductive material, thereby reducing thermal expansion mismatch and preventing micro-cracking while maintaining structural integrity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent modifies the physical and chemical parameters of the conductive filaments to match the thermal expansion characteristics of the carbon fiber composite. By adjusting parameters such as material composition and structural configuration, the thermal expansion coefficient of the conductive elements is optimized to minimize differential expansion and prevent micro-cracking during thermal processing.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If metallic wire is continuously woven from face to face, then electrical conductivity is improved, but resin pockets form due to fiber locking

Engineering Contradiction:
Improveelectrical conductivityVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the conductive filament structure into discrete elements woven through the composite layers rather than continuous wire. This segmentation allows the conductive filaments to be distributed throughout the thickness without continuously locking fibers, enabling proper resin impregnation and eliminating resin pocket formation while maintaining electrical conductivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a weaving process that dynamically adjusts the configuration of conductive filaments as they are integrated into the composite structure. This dynamic weaving approach allows filaments to be positioned and secured without restricting fiber movement during manufacturing, preventing resin pockets while ensuring proper impregnation and structural integrity.

Inventive Principle:
Principle #15Dynamics

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 dissipates electrical current throughout the structure, minimizing damage from lightning strikes and thermal expansion issues, while maintaining structural integrity by distributing electrical charge across the entire depth of the composite.

Implementation Method 1

allowing for continuous electrical current dissipation and preventing localized current concentration through electron tunneling or capacitive coupling

Methodology Applied
Scientific EffectElectron tunneling:

Implementation Method 2

allowing for continuous electrical current dissipation and preventing localized current concentration through electron tunneling or capacitive coupling

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP2540625B1Electrically conductive structure
Publication Date: 2017.08.09 THE BOEING CO
  • EP2540625B1 patent drawingFigure 1~1A
  • EP2540625B1 patent drawingFigure 2~3
  • EP2540625B1 patent drawingFigure 4

AI summary

An electrically conductive structure (100) includes a plurality of carbon fiber layers (101,102) and at least one electrically conductive filament (110) three-dimensionally woven among the carbon fiber layers. The plurality of carbon fiber layers and the at least one electrically conductive filament are operable to conduct electrical current throughout the structure.