Overlapping Cladding Assembly With Epoxy Patches for Watertight Joints

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Solution Overview

Problem

Current methods for assembling structural parts, such as riveting and friction-stir welding, face issues like prolonged downtime, weight penalties, material degradation, and lack of reliability, especially when dealing with composite and metallic materials, and do not ensure a secure and watertight seal.

Innovation Solution

A method using chemical cohesion between overlapping parts through a thermosetting epoxy resin substrate with crosslinking agents, which forms covalent bonds after polymerization, ensuring structural integrity and sealing without the need for additional operations like gluing or welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If riveting is used to assemble structural parts, then structural connection is achieved, but assembly time increases and productivity decreases due to counter-drilling, rivet positioning, and crush control operations

Engineering Contradiction:
Improvestructural connectionVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention extracts and eliminates the most time-consuming operations from the riveting process. By removing the need for counter-drilling, rivet retrieval, and crush control through the use of self-piercing rivets that create their own holes and form heads in a single operation, the assembly time is significantly reduced while maintaining structural connection reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The rivet system performs preliminary actions by automatically creating the hole and forming both heads during the single riveting operation. The rivet pierces the parts and forms its own installation hole and heads simultaneously, eliminating the need for separate preparation operations and thus improving productivity without compromising connection reliability

Inventive Principle:
Principle #10Preliminary action

2Reliability

If riveting is used to assemble structural parts, then structural connection is achieved, but the structure weight increases due to the large number of rivets required

Engineering Contradiction:
Improvestructural connectionVSAvoidstructure weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The invention uses disposable self-piercing rivets that are consumed in the assembly process. These rivets create permanent structural connections through single-use self-piercing operations, eliminating the need for reusable tooling and reducing overall structure weight by replacing traditional multi-component rivet systems with streamlined self-piercing fasteners

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If riveting is used to assemble structural parts, then structural connection is achieved, but coating quality deteriorates due to cracks, fissures, and tool slippage

Engineering Contradiction:
Improvestructural connectionVSAvoidcoating degradation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention replaces the traditional mechanical riveting system with a self-piercing riveting system that eliminates harmful mechanical actions. By using self-piercing rivets that create controlled holes and form heads without requiring external crushing tools or repeated mechanical operations, the system prevents coating degradation from tool slippage and excessive mechanical stress while maintaining reliable structural connections

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

4Reliability

If riveting is used to assemble structural parts, then structural connection is achieved, but environmental pollution increases due to drilling dust and coating degradation

Engineering Contradiction:
Improvestructural connectionVSAvoidpollution
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention converts the potentially harmful drilling operation into a beneficial self-piercing process. By using self-piercing rivets that create controlled, clean holes without traditional drilling, the system eliminates drilling dust pollution while maintaining structural connection reliability. The self-piercing action benefits from controlled material displacement rather than chaotic drilling, reducing environmental contamination

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

5Reliability

If riveting is used to assemble structural parts, then structural connection is achieved, but assembly complexity increases due to significant tooling requirements for cutting, drilling, and chamfering

Engineering Contradiction:
Improvestructural connectionVSAvoidtooling complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges multiple separate operations (cutting, drilling, chamfering, rivet installation) into a single self-piercing riveting operation. By combining hole creation, rivet installation, and head formation into one integrated process using self-piercing rivets, the system reduces tooling complexity while ensuring reliable structural connections through standardized equipment

Inventive Principle:
Principle #5Merging (Combining)

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 provides a reliable, efficient, and structurally sound assembly that ensures cohesion and connection, reducing the risk of damage and delamination, while avoiding the drawbacks of traditional riveting and welding methods.

Implementation Method 1

a thermosetting intermediate, in particular a thermosetting epoxy resin substrate with crosslinking agents, which forms covalent bonds between these ends after polymerization

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP3752345B1Method for assembling cladding parts and structures comprising parts thus assembled
Publication Date: 2022.02.02 CKP ENG
  • EP3752345B1 patent drawingFigure 1a~2c
  • EP3752345B1 patent drawingFigure 3a~3c
  • EP3752345B1 patent drawingFigure 4a~6

AI summary

The invention relates to a method for assembling two parts (100, 300) by means of overlapping edges (1, 3), each part (100, 300) being made of a composite, metal or thermoplastic material, according to the following steps: - producing at least one patch (2) comprising an epoxy resin substrate incorporating a crosslinking agent, the resin being bi-phasic or monophasic; - in the preparation phase, positioning the patches (2) along an edge (1) of a first part (100) by adhesion of the patches (2) along a seam line of a first part (100); - in the assembly phase, superimposing the edge (3) of the other part (300) on the edge (1) of the first part (100) so as to sandwich the patches (2) between the edges (1, 3); - attaching the edges (1, 3) to the patches (2) by means of a supply of energy enabling total polymerisation of the patches (2), which chemically bond to the edges (1,3), and - cooling the edges (1, 3) of the parts (100, 300). The invention is applicable to transport structures, in particular heavier-than-air aircraft.