Composite Fluid Transport Member Lightning Protection

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Solution Overview

Problem

Aircraft fuel transport systems using carbon fiber reinforced plastic materials are prone to higher induced voltages and currents from lightning, leading to undesired electrical discharges, which existing methods struggle to manage effectively due to weight and cost constraints, and safety concerns from electrostatic charge buildup.

Innovation Solution

Incorporating transport members with selected electrical resistance levels, typically above 100 kilohms per meter, made from non-metallic fiber reinforced composite materials, to limit induced voltages and currents, and using coupling assemblies with conductive pathways to dissipate electrostatic charge, thereby reducing electrical discharges to within safe tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal tubing is used in carbon fiber reinforced plastic aircraft, then fuel transport is achieved, but induced voltages from lightning cause undesired electrical discharges

Engineering Contradiction:
Improveelectrical safetyVSAvoidlightning-induced voltages
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces high resistance electrical isolators as intermediary components within the metal tubing system. These isolators act as mediators that block the path for lightning-induced currents while allowing the fuel transport function to continue. The isolators are positioned at strategic locations to constrain voltages and currents without requiring complete system replacement.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite material construction by combining metal tubing with high resistance electrical isolator materials. This creates a hybrid system that maintains the mechanical strength and fuel compatibility of metal while adding the electrical isolation properties of the isolator material, thereby reducing lightning-induced electrical discharges.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If high resistance electrical isolators are inserted into metal tubing, then induced voltages are constrained, but weight and expense increase

Engineering Contradiction:
Improveinduced voltagesVSAvoidsystem weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The patent utilizes high resistance electrical isolators that are relatively simple, inexpensive components compared to replacing the entire metal tubing system. These isolators provide the necessary electrical protection at minimal cost and weight addition, representing a cost-effective solution to the lightning-induced voltage problem.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Object-affected harmful factors

If high resistance electrical isolators are installed, then electrical discharge intensity is reduced, but protection against remaining arcing requires additional measures

Engineering Contradiction:
Improveelectrical discharge intensityVSAvoidsystem complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent divides the fuel transport system into segmented sections by inserting electrical isolators at specific locations. This segmentation breaks up continuous conductive paths, constraining voltages and currents to specific segments. The isolators create discrete electrical zones that can be independently managed, reducing overall discharge intensity without requiring complete system redesign.

Inventive Principle:
Principle #1Segmentation

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 constrains lightning-induced voltages and currents, reducing the intensity of electrical discharges and allowing safe dissipation of electrostatic charge, thus enhancing safety and reducing operational costs by minimizing the need for heavy metal isolators.

Implementation Method 1

the transport member (200) is comprised of a material configured to reduce voltages and currents, induced in response to an electromagnetic event, along the transport member (200)

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

allowing static dissipation along the fluid transport system

Methodology Applied
Scientific EffectElectrostatic Discharge: Electrostatic Discharge

Data Source

PatentEP2672156B1Composite tubes for a fluid transport system
Publication Date: 2021.03.24 THE BOEING CO
  • EP2672156B1 patent drawingFigure 1
  • EP2672156B1 patent drawingFigure 2
  • EP2672156B1 patent drawingFigure 3

AI summary

A method and apparatus for reducing an intensity of an electrical discharge that occurs within a fluid transport system in an aerospace vehicle. In one illustrative embodiment, an apparatus comprises a transport member. The transport member is configured for use in the fluid transport system. The transport member is comprised of a material configured to reduce voltages and currents, induced in response to an electromagnetic event, along the transport member.