Fiber metal laminates comprising electrically insulated carbon fibers

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Solution Overview

Problem

The use of carbon fibers in fiber-metal laminates with aluminum is hindered by electrolytic corrosion due to the potential difference between carbon and aluminum, limiting their application in aircraft construction despite their desirable low weight and high strength properties.

Innovation Solution

The application of an electrically insulating coating on carbon fibers using (meth) acrylic acid polyglycolester, which prevents electrolytic corrosion when in contact with aluminum, and the incorporation of lithium triflate for conductive coatings to enable the creation of structural batteries for energy storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If carbon fibers are used in fiber-metal laminates with aluminum, then weight is reduced and strength is improved, but electrolytic corrosion occurs due to potential difference between carbon and aluminum

Engineering Contradiction:
ImproveweightVSAvoidelectrolytic corrosion
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

An electrically insulating coating layer is applied to the carbon fibers to act as an intermediary barrier between the carbon fibers and aluminum sheets. This coating prevents direct electrical contact and eliminates the galvanic cell formation that causes electrolytic corrosion, while still allowing the carbon fiber-reinforced plastic laminate to maintain its structural strength and low weight properties when combined with aluminum.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 coated carbon fibers prevent electrolytic corrosion and allow for the creation of functional layers in aircraft structures, enhancing structural performance and enabling energy storage capabilities without compromising the material's integrity.

Implementation Method 1

the coating is electrically insulating, helps the disadvantages of the stand of the technology. POLY (meth) acrylic acid polyglycolester are used as insulating coating of the individual fibers

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

The monomers are polymerized by electropolymerization on the carbon fibers ('grown'). The (meth) acrylic acid polyglycolester are used in dimethylformamide. In this solution, the carbon fibers are immersed, as a cathode, and on its surface, a layer of poly (meth) acrylic acid polycolesters forms on its surface

Methodology Applied
Scientific EffectElectropolymerization: Electrodeposition

Implementation Method 3

the incorporation of lithium triflate for conductive coatings to enable the creation of structural batteries for energy storage

Methodology Applied
Scientific EffectIonic conduction: Fast Ion Conductor

Data Source

PatentEP3969274B1Fiber metal laminates comprising electrically insulated carbon fibers
Publication Date: 2023.02.15 AIRBUS OPERATIONS GMBH
  • EP3969274B1 patent drawingFigure 1~4
  • EP3969274B1 patent drawingFigure 5

AI summary

The invention relates to a layer composite for an aircraft or spacecraft, containing coated first carbon fibers, the coating having an electrically insulating effect.