Fiber Composite Bonding With Undulating Threads for Residual Strength

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Solution Overview

Problem

Current adhesive arrangements for fiber composite components in aircraft construction face challenges in achieving sufficient residual strength and reliability due to the use of rivets, which can damage load-bearing fibers and result in corrosion, and existing adhesives lack the necessary strength and reliability for structural bonding.

Innovation Solution

The introduction of undulating threads within the fiber composite components, which protrude from the surface and are embedded into the adhesive layer, providing a positive locking fit that enhances adhesion strength and reliability, and includes the use of thermosetting or thermoplastic matrix materials with carbon or glass fibers, and textile layers for reinforcement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rivets are used for structural bonding, then mechanical strength and reliability are improved, but weight increases, load-bearing fibers are damaged, and corrosion risk increases

Engineering Contradiction:

Improvebond reliabilityVSAvoidcomponent weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces the mechanical fastening system (rivets) with a chemical bonding system (adhesive). The adhesive is applied to bond fiber composite components, eliminating the need for mechanical fasteners. This substitution reduces weight by removing rivet mass and associated hole structures, while avoiding damage to load-bearing fibers that occurs during drilling and rivet installation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the bonding mechanism from mechanical (rivets requiring hole formation) to chemical (adhesive bonding). This parameter change allows bonding without drilling holes, thereby preventing damage to load-bearing fibers and eliminating the source of corrosion that arises from hole formation and rivet installation.

Inventive Principle:

Principle #35Parameter changes

2Strength

If rivets are used for structural bonding, then mechanical strength is improved, but load-bearing fibers are damaged

Engineering Contradiction:

Improvebond strengthVSAvoidfiber damage

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical fastening (rivets requiring hole formation) with chemical bonding (adhesive). This eliminates the drilling process that damages load-bearing fibers, while the adhesive provides sufficient bond strength through chemical adhesion to the fiber composite surface without requiring physical penetration or hole formation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Weight of moving object

If adhesive bonding is used instead of rivets, then weight is reduced and fiber damage is avoided, but residual strength and reliability are insufficient

Engineering Contradiction:

Improvecomponent weightVSAvoidbond reliability

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent embeds reinforcement elements (such as fiber mats or additional fiber layers) within the adhesive layer or at the bonding interface. These nested reinforcement elements provide additional structural support and residual strength while maintaining the weight advantages of adhesive bonding over riveted connections.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent employs composite material structures at the bonding interface, combining the adhesive with reinforcement fibers or hybrid material systems. This composite approach enhances the reliability and residual strength of the adhesive bond while maintaining the weight reduction benefits of eliminating rivets.

Inventive Principle:

Principle #40Composite materials

4Object-affected harmful factors

If adhesive bonding is used instead of rivets, then corrosion risk is reduced, but bond strength and reliability are insufficient

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidbond strength

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent uses composite material systems combining adhesive with reinforcement elements to achieve both high bond strength and corrosion resistance. The composite structure at the bonding interface provides mechanical strength while the adhesive system eliminates the corrosion-prone metal-to-composite interfaces created by rivets.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10047465B2Method for manufacturing a fiber composite component

Publication Date: 2018.08.14 AIRBUS DEFENCE & SPACE GMBH

AI summary

A fiber composite component includes a composite including cured matrix material and a fiber material embedded therein. At least one partial area of the fiber composite component is provided with at least one thread, which undulates as it extends along a surface area of the composite, so that sections of the thread alternately run inside of the composite and outside of the composite. An adhesive arrangement for such fiber composite components is also disclosed. Finally, methods for manufacturing such a fiber composite component or for manufacturing such an adhesive arrangement are disclosed.