Corrosion-Resistant Joining Devices Using Prepreg E-Glass Films
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Solution Overview
Problem
Existing permanent joining methods using glues for structural elements face issues such as structural failures due to over-tensioning, poor alignment, and corrosion from galvanic contact, especially in composite materials, and are difficult to inspect and maintain, while non-permanent joints are needed for insulation, conductivity, and corrosion protection.
Innovation Solution
Non-permanent, corrosion-resistant joining devices using prepreg E-Glass + epoxy resin films coated on washers or screws, which provide electrical insulation and prevent galvanic corrosion without increasing weight or interfering with design calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If permanent joining methods using glues are used for structural elements, then structural resistance and chemical/thermal inertia are improved, but the joints become difficult to inspect and maintain, and structural failures may occur due to over-tensioning or poor alignment
Solution Approach 1:
The joining system is segmented into modular components: structural fasteners (screws, bolts) for mechanical strength, separate insulation components, and distinct fastening elements. This segmentation allows each component to be independently inspected, removed, and replaced without affecting the entire joint assembly, resolving the contradiction between permanent fixation and maintainability.
Solution Approach 2:
The joining system transitions from static permanent bonds to dynamic non-permanent connections using threaded fasteners that can be loosened, removed, and reinstalled. This dynamic characteristic enables inspection and maintenance operations while maintaining structural integrity during normal operation.
2Ease of repair
If non-permanent joining elements are used for insulation and conductivity components, then ease of maintenance and inspection is improved, but corrosion mechanisms due to galvanic contact between different materials are triggered
Solution Approach 1:
Non-conductive washers and insulation components serve as intermediary elements between dissimilar metallic fasteners and structural elements. These intermediaries electrically isolate the contact surfaces, preventing galvanic cell formation while still providing mechanical fastening function, thus eliminating corrosion risk while maintaining non-permanent joinability.
Solution Approach 2:
Thin non-conductive film coatings or washer elements are applied at critical contact points between dissimilar metals. These thin barriers provide electrical insulation sufficient to prevent galvanic corrosion while maintaining the thin-profile design and non-permanent nature of the joining system.
3Adaptability or versatility
If dissimilar materials are combined in composite structures, then structural requirements and chemical/thermal properties are improved, but corrosion mechanisms due to galvanic contact are triggered
Solution Approach 1:
Instead of uniformly treating all material interfaces, non-conductive protective elements are applied locally only at specific contact points between dissimilar metals where galvanic corrosion risk exists. This localized approach maintains the benefits of dissimilar material combinations while providing targeted corrosion protection at critical interfaces.
4Strength
If glues are used for permanent fixing, then structural resistance is improved, but costly preparation of facing surfaces and lengthy laying times are required
Solution Approach 1:
The patent replaces chemical bonding mechanisms (glues requiring surface preparation and curing time) with mechanical fastening systems (threaded fasteners providing immediate structural strength). This substitution eliminates surface preparation steps and lengthy laying times while maintaining or improving joint strength through proven mechanical connection methods.
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 solution effectively prevents corrosion and ensures durable, adaptable, and inspectable non-permanent joints with maintained mechanical resistance and aesthetic appearance, eliminating the need for additional corrosion protection measures.
Implementation Method 1
coating the outer surface of the washer with a prepreg E-Glass + epoxy resin film... which provide electrical insulation and prevent galvanic corrosion
Data Source
Figure 1~2
Figure 3~4
AI summary
A non-permanent, corrosion-resistant joining device, which comprises, on at least a part (15) of a surface of an element of a joint (11, 12) facing a structural element (20) made of at least one composite material, at least a film of prepreg E-Glass and epoxy resin (13, 113). The joining device can be a screw (11), a nut or a washer (12). A method for the production of a non-permanent, corrosion-resistant joining device in which the coating is effected of at least a part (15) of a surface of an element of a joint (11, 12) facing a structural element (20) made of at least one composite material with at least a film of prepreg E-Glass and epoxy resin (13, 113).