Rubber-Modified Honeycomb Edge Coating for Composite Panel Bonding
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Solution Overview
Problem
The challenge in sandwich panels, particularly those with honeycomb cores, is achieving a strong bond between the face sheets and the honeycomb core while minimizing weight and avoiding the need for separate adhesive layers, especially when dealing with composite materials and 'fuzzy' edges formed during honeycomb slicing.
Innovation Solution
The use of a polyamide and/or rubber-containing adhesive applied to the edges of the honeycomb core provides a strong bond with face sheets, enhancing the bonding strength and eliminating the need for surface treatment of fuzzy edges, thereby improving the structural integrity and reducing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a separate adhesive layer is used to bond face sheets to honeycomb core, then bond strength is improved, but weight increases and device complexity increases
Solution Approach 1:
The patent combines the adhesive layer and face sheet into a single integrated component. The face sheet is fabricated with an adhesive layer pre-applied to its rear surface, eliminating the need for a separate adhesive layer. This merging reduces the number of components, decreases weight, and simplifies the bonding process while maintaining strong adhesion between the face sheet and honeycomb core.
Solution Approach 2:
The integrated face sheet with pre-applied adhesive serves multiple functions: it provides structural strength, enables bonding to the honeycomb core, and eliminates the need for separate adhesive application steps. This multi-functional design reduces device complexity and streamlines manufacturing while achieving both weight reduction and adequate bond strength.
2Productivity
If honeycomb edges are left untreated after slicing, then manufacturing time is reduced, but bond strength deteriorates due to fuzzy edges
Solution Approach 1:
The adhesive layer is pre-applied to the face sheet during its fabrication process, before the face sheet is bonded to the honeycomb core. This preliminary action ensures that the adhesive is already in position and properly distributed, eliminating the need for additional edge treatment of the honeycomb. The pre-applied adhesive compensates for the fuzzy edges, maintaining bond strength without requiring post-slicing treatment.
Solution Approach 2:
The adhesive layer acts as an intermediary between the face sheet and the honeycomb core edges. It mediates the bonding interface, allowing the fuzzy edges to be bonded effectively without requiring mechanical or chemical treatment. The adhesive fills in and bonds to the irregular surface, maintaining strong adhesion while eliminating the need for time-consuming edge preparation steps.
3Weight of moving object
If self-adhesive composite face sheets are used, then weight is reduced and adhesive layers are eliminated, but bond strength may be insufficient
Solution Approach 1:
The patent modifies the parameters of the self-adhesive face sheet by incorporating a specifically formulated adhesive layer with controlled thickness, viscosity, and curing characteristics. The adhesive layer is designed with optimal properties to achieve both weight reduction and sufficient bond strength. By adjusting parameters such as adhesive composition and application method, the solution maintains the weight benefits of self-adhesive sheets while ensuring adequate bonding performance.
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 solution results in a significant increase in bond strength between the honeycomb and face sheets, leading to core failure rather than cohesive failure during peel tests, and allows for the elimination of time-consuming edge treatment processes, while maintaining lightweight and structural strength.
Implementation Method 1
an adhesive that includes polyamide (a common example of which is commonly referred to as 'nymn') and/or rubber is used to bond the face sheet to the honeycomb
Data Source
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AI summary
Core-skin bonding is improved between honeycomb and composite face sheets by applying a polyamide and/or rubber-containing adhesive to the edge of the honeycomb prior to bonding. Edge coating of honeycomb with a polyamide and/or rubber-containing adhesive is useful in further increasing the bond strength between honeycomb and prepreg face sheets, especially when the matrix resin of the prepreg is designed to adhere the prepreg to the honeycomb without the use of a separate structural adhesive.