Hybrid Structure Isolating Dissimilar Materials

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Solution Overview

Problem

Galvanic corrosion in aircraft components made from composite materials like carbon-fiber-reinforced polymer (CFRP) and metallic materials, such as aluminum and titanium, occurs due to differences in electrode potentials, leading to inefficient and time-consuming manufacturing processes when trying to prevent moisture ingress with traditional sealant application methods.

Innovation Solution

A method involving a sub-assembly with a sealant and an isolation sheet, fabricated from materials with different electrode potentials, is applied to prevent direct contact between CFRP and metallic components, allowing for reduced manufacturing time and minimizing distortion by pre-installing the sealant and isolation sheet, thus preventing the formation of a galvanic cell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional sealant application method is used (applying sealant after hole locations are determined), then galvanic corrosion prevention is achieved, but manufacturing time increases and part distortion occurs

Engineering Contradiction:

Improvegalvanic corrosion preventionVSAvoidmanufacturing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies sealant to the first component before coupling the second component, and pre-installs the isolation sheet on the sealant before final assembly. This preliminary application of protective measures eliminates the need for intermediate removal and re-alignment steps, reducing manufacturing time while maintaining corrosion prevention effectiveness

Inventive Principle:

Principle #10Preliminary action

2Reliability

If traditional sealant application method is used (removing metallic component for sealant application), then galvanic corrosion prevention is achieved, but manufacturing complexity increases

Engineering Contradiction:

Improvegalvanic corrosion preventionVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The sealant and isolation sheet are applied and installed in advance before final assembly, eliminating the need to remove the metallic component intermediate step. This preliminary preparation simplifies the overall manufacturing process while achieving the same corrosion prevention outcome

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The isolation sheet serves as an intermediary layer between the sealant and the second component, providing an additional barrier against moisture ingress and simplifying the assembly process by pre-positioning the protective barrier

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If traditional sealant application method is used (intermediate removal and re-alignment), then galvanic corrosion prevention is achieved, but part distortion increases

Engineering Contradiction:

Improvegalvanic corrosion preventionVSAvoidhole alignment precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The sealant is applied and the isolation sheet is installed before final coupling, eliminating intermediate removal and re-alignment steps. This prevents ambient condition changes from causing part distortion and maintains hole alignment precision throughout the manufacturing process

Inventive Principle:

Principle #10Preliminary action

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

This approach effectively prevents galvanic corrosion by maintaining separation between components, reducing manufacturing time, and minimizing distortion issues, even in the presence of moisture, by using a pre-installed sealant and isolation sheet in the sub-assembly.

Implementation Method 1

Galvanic corrosion refers to an electrochemical process where in electrons are transferred between materials in electrical contact that have different electrode potentials. A galvanic cell generally includes an anode, a cathode, and an electrolyte that couples the anode and cathode together in electrical contact.

Methodology Applied

Scientific EffectGalvanic corrosion: Electrolyte

Implementation Method 2

In such assemblies, certain metallic materials have a more active electrode potential than the conductive carbon fibers dispersed within the composite materials.

Methodology Applied

Scientific EffectElectrode potential difference: Electric Field

Data Source

PatentUS10265914B2Hybrid structure and methods for forming the same

Publication Date: 2019.04.23 THE BOEING CO

AI summary

A method for forming a hybrid structure is provided. The method includes applying a sealant to a first component fabricated from a first material, coupling an isolation sheet to the sealant, and coupling a second component to the isolation sheet. The isolation sheet and the second component are fabricated from a second material that is different than the first material to facilitate preventing formation of a galvanic cell within the hybrid structure.