Fiber-Reinforced Plastic Joining via Recess Injection
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Solution Overview
Problem
Existing methods for joining fiber-reinforced plastic aircraft parts, such as riveting and adhesive bonding, are time-intensive, weaken the structure, and do not optimize weight or load distribution, while also posing health risks and limitations in nondestructive testing.
Innovation Solution
A method involving the creation of depressions on the surfaces of fiber-reinforced adherends, which are filled with a fiber-containing plastic material that cures to form a strong, positive adhesive bond, eliminating the need for spacers and allowing for automated, high-quality joining with reduced cycle times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If riveting methods are used to join fiber-reinforced adherends, then the adherends can be firmly connected, but the structure is weakened by rivet holes, fiber tears, and delamination
Solution Approach 1:
The invention divides the joining process into distinct phases: creating recesses in the adherends, injecting adhesive material into these recesses, and curing the adhesive. This segmentation allows each phase to be optimized independently, ensuring strong connections without structural damage.
Solution Approach 2:
The invention introduces an intermediary adhesive material that fills the interface between adherends. This adhesive mediator creates a positive fit through the tooth system formed by recesses, distributing loads evenly and preventing direct mechanical contact that would cause fiber tears and delamination.
2Strength
If riveting methods are used to join adherends, then the adherends can be connected, but the process becomes very time-intensive due to multiple individual steps
Solution Approach 1:
The invention combines multiple operations into a single integrated process. The recess creation and adhesive injection are performed in one continuous operation, eliminating the need for separate steps of aligning, hole preparation, cleaning, and rivet installation that characterize traditional riveting methods.
Solution Approach 2:
The recesses are pre-formed in the adherends before the actual joining operation. This preliminary action prepares the surfaces in advance, allowing the adhesive to be injected directly into predetermined locations, thereby reducing the overall cycle time and enabling convenient automation.
3Reliability
If adhesive bonding methods are used to join adherends, then the adherends can be connected without rivet holes, but the bonding surfaces require very high cleanliness or complicated cleaning measures
Solution Approach 1:
The invention applies local quality by creating recesses only in specific areas where bonding is required, rather than requiring the entire bonding surface to be perfectly clean. The adhesive is injected directly into these localized recesses, concentrating the bonding action where it is most needed and reducing the overall surface preparation requirements.
4Reliability
If adhesive bonding methods are used to join adherends, then the adherends can be connected, but the adhesives require a certain curing period that makes the bonding methods time-intensive
Solution Approach 1:
The invention utilizes parameter changes by controlling the curing process of the adhesive material. The adhesive is injected in a liquid or fluid state, allowing for quick placement and alignment, and then undergoes a controlled curing transformation to achieve rapid strength development, thereby reducing the overall curing time compared to traditional adhesive bonding methods.
5Strength
If riveting or bonding methods are used to join adherends, then the adherends can be connected, but a material overlap is required that is not optimized in terms of weight and creates incremental load flow
Solution Approach 1:
The invention transitions from a two-dimensional overlap joint to a three-dimensional joining structure by creating recesses that extend into the thickness of the adherends. This dimensional change allows the adhesive to be contained within the recesses, eliminating the need for surface overlap and reducing the overall component weight while maintaining or improving joining strength.
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 produces a high-strength butt joint seam that matches the strength of the adherends, optimizing weight and load distribution, and enabling efficient, repeatable joining with improved safety and quality.
Implementation Method 1
The plastic material is then cured or set
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
Disclosed are a method for firmly joining fiber-reinforced, plastic-based adherends (2,4), wherein depressions (22,24) are introduced into opposing lateral surfaces (26,28) of the adherends, and have injected into them a fiber-reinforced plastic material (42) that serves as an adhesive, a device (1) for implementing such a method, as well as a component (58) joined in this way.