Fibre Composite Co-Curing Joints for Hydrogen-Tight Tank Structures

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Solution Overview

Problem

Existing methods for manufacturing composite structures, particularly liquid hydrogen tanks, face challenges in ensuring hydrogen tightness and mechanical performance due to the use of carbon fibre reinforced plastics, where traditional joining techniques like adhesive bonding and riveting are not suitable, posing safety risks and requiring additional support elements.

Innovation Solution

A fibre composite material with regions of differing curing properties is used, allowing for covalent bonding between substructures during assembly, eliminating the need for rivets or bolts by forming reliable and tight joints through controlled curing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional joining techniques like adhesive bonding and riveting are used for composite structures, then mechanical strength can be achieved, but hydrogen tightness is compromised and additional support elements are required

Engineering Contradiction:
Improvemechanical strengthVSAvoidhydrogen tightness
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces traditional mechanical joining systems (adhesive bonding and riveting) with a chemical bonding system based on covalent bonds. The fibre composite material incorporates reactive groups in its matrix that form covalent bonds with opposing composite materials during assembly, eliminating the need for separate joining elements and ensuring both mechanical strength and hydrogen tightness through a unified bonding mechanism.

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

Solution Approach 2:

The invention uses a composite material system where the matrix contains both structural fibres for mechanical strength and reactive chemical groups for bonding. This integration of structural and bonding functions within a single composite material eliminates the need for separate joining materials and ensures consistent hydrogen tightness while maintaining mechanical performance.

Inventive Principle:
Principle #40Composite materials

2Reliability

If rivets or bolts are used to provide secondary load path, then joint reliability is improved, but the structure becomes more complex and tightness requirements are violated

Engineering Contradiction:
Improvejoint reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical fastening systems (rivets and bolts) with a chemical bonding system. The reactive groups in the matrix form covalent bonds that provide both the secondary load path and joint reliability traditionally achieved by mechanical fasteners, while eliminating the need for additional holes, fasteners, and assembly complexity.

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

3Ease of manufacture

If adhesive bonding is used to join substructures, then assembly is simplified, but hydrogen tightness and mechanical performance are compromised

Engineering Contradiction:
Improveassembly simplicityVSAvoidhydrogen tightness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention integrates the bonding function directly into the composite material structure. The matrix contains reactive groups that form covalent bonds with opposing materials, eliminating the need for separate adhesive layers while maintaining assembly simplicity and ensuring hydrogen tightness through the inherent chemical bonding of the composite material itself.

Inventive Principle:
Principle #40Composite materials

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 method enables high-performance, reliable joints with enhanced mechanical properties and tightness, reducing the need for additional joining methods and improving manufacturing efficiency in complex structures like LH2 tanks.

Implementation Method 1

the polymer matrix being formed by a curable resin and comprising at least one first region having a first curing property of the resin and at least one second region having a second curing property of the resin

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Implementation Method 2

co-curing the second region of the first substructure and the second region of the second substructure after contacting to form the composite structure... establishing a chemical or covalent bond between the regions

Methodology Applied
Scientific EffectCovalent bond: Chemical Bonding

Data Source

PatentEP4650155A1Fibre composite material, a method of manufacturing a composite structure and composite structure
Publication Date: 2025.11.19 AIRBUS (SAS)
  • EP4650155A1 patent drawingFigure 1~2
  • EP4650155A1 patent drawingFigure 3a~3b
  • EP4650155A1 patent drawingFigure 3c~4

AI summary

The present invention provides a fibre composite material (10) containing at least one layer of reinforcing fibres embedded in a polymer matrix (11), with the polymer matrix (11) being formed by a curable resin and comprising at least one first region (100) having a first curing property of the resin and at least one second region (200) having a second curing property of the resin, wherein the at least one first curing property is different from the at least one second curing property, a method of manufacturing a composite structure (12), and a composite structure (12) manufactured in the method.