Composite Fiber Joint Structure for Lightning Current Continuity

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Solution Overview

Problem

Composite material structures with conductive reinforcing fibers covered in non-conductive resin cannot effectively implement lightning proofing measures, as existing methods do not provide adequate electrical continuity for lightning protection.

Innovation Solution

A composite material structure is created by integrating conductive reinforcing fibers with a low-conductivity material that has lower electrical resistance than the resin, allowing for appropriate lightning protection by electrically connecting the fibers, and optionally using an insulating adhesive layer and fasteners to further enhance lightning path management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If composite materials with resin-impregnated reinforcing fibers are used for structure integration, then weight reduction and cost reduction are achieved, but electrical continuity for lightning proofing is lost

Engineering Contradiction:

Improvestructure weightVSAvoidlightning proofing capability

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

A low-conductivity material is introduced as an intermediary component between composite material sections. This material has electrical resistance lower than the resin but higher than the reinforcing fibers, creating a controlled electrical path that allows lightning current to pass through the structure while maintaining the insulating properties of the resin-impregnated fibers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a hybrid structure combining composite materials with a low-conductivity material layer. This composite approach integrates the weight-saving benefits of fiber-reinforced plastics with the electrical continuity requirements for lightning protection, forming a multi-layer structure with differentiated electrical properties.

Inventive Principle:

Principle #40Composite materials

2Reliability

If metal materials are integrated via insulating material for lightning proofing, then electrical continuity is provided, but the lightning protection effectiveness is insufficient for composite structures

Engineering Contradiction:

Improveelectrical continuityVSAvoidlightning damage risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The low-conductivity material is strategically positioned at specific locations where electrical continuity is needed, such as between composite sections or at attachment points. This localized approach provides electrical continuity only where required for lightning protection, while maintaining the insulating properties of the resin-impregnated fibers in other areas.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If conductive reinforcing fibers are covered with non-conductive resin, then composite material properties are achieved, but electrical path for lightning protection is interrupted

Engineering Contradiction:

Improvecomposite material fabricationVSAvoidelectrical conductivity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The structure is segmented into multiple sections, each maintaining its insulating resin-impregnated fiber properties, with discrete low-conductivity material bridges connecting these sections. This segmentation allows each component to retain its manufacturing advantages while the assembled structure achieves the required electrical continuity for lightning protection.

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 passes lightning electricity through the composite material structure without damage, providing appropriate lightning proofing while reducing costs and weight, and suppressing excessive Joule heat and dielectric breakdown.

Implementation Method 1

a low-conductivity material having a lower electrical resistance than that of the first resin and the second resin and a low conductivity greater than or equal to that of the first reinforcing fiber and the second reinforcing fiber, the low-conductivity material electrically connecting the first reinforcing fiber to the second reinforcing fiber

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS11763958B2Composite material structure and method for manufacturing composite material structure

Publication Date: 2023.09.19 MITSUBISHI HEAVY IND LTD

AI summary

Provided are a composite material structure obtained by joining composite materials with resin-impregnated reinforcing fibers, for which appropriate lightning proofing measures are taken, and a method for manufacturing the composite material structure. The composite material structure includes a first composite material, a second composite material, and a low-conductivity material. The first composite material includes a conductive first reinforcing fiber and a first resin impregnated into the first reinforcing fiber. The second composite material is integrated with the first composite material, and has a conductive second reinforcing fiber and a second resin impregnated into the second reinforcing fiber. The low-conductivity material has an electrical resistance that is lower than that of the first resin and the second resin and a low conductivity that is greater than or equal to the first reinforcing fiber and the second reinforcing fiber, and electrically connects the first reinforcing fiber to the second reinforcing fiber.