Fibre Composite Bonding via Reinforcement Element Integration

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Solution Overview

Problem

Current methods for manufacturing fibre composite components, such as aircraft fuselage shells, rely heavily on riveting or welding for bonding longitudinal stiffeners to the skin field, which increases assembly costs and weight, and may lead to delamination and buckling issues, while also requiring precise machining and material considerations to prevent corrosion.

Innovation Solution

A method involving the integration of a preform reinforcement element with a bonding surface into the base element, allowing for an optimal force introduction and material bonding of ancillary elements, using fibre layers that transition seamlessly into the base element, enabling a strong and damage-tolerant adhesive joint without the need for conventional mechanical attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rivets are used to bond longitudinal stiffeners to the skin field, then the bonding strength and structural stability are improved, but the assembly costs and weight increase

Engineering Contradiction:
Improvebonding strengthVSAvoidweight of fuselage shell
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The patent replaces the mechanical riveting system with a chemical adhesive bonding system. The adhesive layer bonds the longitudinal stiffener directly to the skin field without requiring rivets, thereby reducing weight while maintaining bonding strength. This substitution eliminates the need for rivet holes and mechanical fasteners.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs composite material structures where the adhesive layer acts as an intermediate material between the stiffener and skin field. This composite approach allows for optimized bonding performance while reducing the overall weight compared to metal rivet connections.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If rivet holes are machined precisely to prevent weakening of fibrous material, then the structural integrity is improved, but the manufacturing complexity and costs increase

Engineering Contradiction:
Improveprecision of rivet hole machiningVSAvoidcomplexity of manufacturing process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent eliminates the mechanical drilling and machining operations for rivet holes by using adhesive bonding instead. This substitution removes the need for precise hole positioning and drilling equipment, significantly simplifying the manufacturing process while maintaining structural integrity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the riveting process entirely from the manufacturing workflow. By eliminating the rivet hole machining step, the manufacturing process becomes simpler and less complex, while the adhesive bonding provides sufficient structural performance.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If longitudinal stiffeners are adhesively bonded onto the cured skin field, then the assembly process is simplified, but the bonding joint strength and damage tolerance are reduced

Engineering Contradiction:
Improveease of bonding processVSAvoidbonding joint strength
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent incorporates bonding preparation actions into the skin field manufacturing process itself. The skin field is manufactured with pre-prepared bonding surfaces and appropriate adhesive layers are applied during the curing process, ensuring optimal bonding conditions are established before the stiffeners are attached. This preliminary preparation enhances bonding strength while maintaining ease of assembly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent optimizes bonding parameters including adhesive layer thickness, surface preparation methods, and curing conditions. By carefully controlling these parameters, the bonding joint achieves both high strength and damage tolerance while maintaining the simplicity of the adhesive bonding process.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If material of rivets is carefully selected to prevent corrosion, then the durability is improved, but the assembly costs and manufacturing complexity increase

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidcomplexity of material selection and assembly
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the rivet connection system with an all-composite adhesive bonding system. This eliminates the need for metal rivets that could corrode when in contact with carbon fibres or moisture. The adhesive bonding system provides inherent corrosion resistance without requiring complex material selection or protective measures.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses homogeneous composite materials throughout the bonding system - the adhesive is compatible with both the skin field and longitudinal stiffener materials. This homogeneity eliminates galvanic corrosion issues that arise from dissimilar metal contacts and simplifies the overall material selection process.

Inventive Principle:
Principle #33Homogeneity

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 method enhances the load-bearing capacity and damage tolerance of fibre composite components by creating a mechanically intermeshed bond between the base and ancillary elements, preventing delamination and reducing the need for additional mechanical fastening, thus improving the structural integrity and reducing assembly complexities.

Implementation Method 1

a bonding surface for purposes of bonding an ancillary element... enabling a strong and damage-tolerant adhesive joint

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP2694276B1A method for the manufacture of a fibre composite component and a fibre composite component
Publication Date: 2019.08.14 AIRBUS OPERATIONS GMBH
  • EP2694276B1 patent drawingFigure 1~2
  • EP2694276B1 patent drawingFigure 3~4
  • EP2694276B1 patent drawingFigure 5

AI summary

Disclosed is a method for the manufacture of a fibre composite component (1) with a base element (2), and with at least one ancillary element (4,6) bonded to the base element (2), wherein a reinforcement element (26) is introduced in at least one bonding region of the base element (2) or the ancillary element (4,6) for purposes of developing a bonding surface for the ancillary element (4,6) or the base element (2), a reinforcement element with fibre sections (46,48), the ends of which emanate from a bonding surface (22), also a fibre composite component with a base element (2), in the bonding regions of which reinforcement elements are introduced, on the bonding surfaces of which ancillary elements (4,6) are bonded with one such.