Composite Hole Plug Structure for Vacuum-Assisted Repair Bonding
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Solution Overview
Problem
The challenge in repairing composite structures, such as carbon fiber reinforced polymers, lies in accessing and applying a vacuum force during the curing process, as hollow areas between layers can prevent effective debulking and adhesion, leading to incomplete repairs and potential lifting of repair patches.
Innovation Solution
A hole plug with a flange, bevel, shank, and nubs is designed to fill the opening through the composite layers, facilitating the application of adhesive and vacuum force, ensuring proper bonding and debulking by matching the countersink angle and providing additional adhesive carriers and frictional resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vacuum force is applied during the curing process, then the debulking and adhesion improve, but hollow areas between layers prevent effective vacuum application
Solution Approach 1:
The hole plug acts as an intermediary component that fills hollow areas between composite layers, enabling vacuum force transmission to the repair patch while preventing vacuum loss into void spaces
Solution Approach 2:
The hole plug is a simple, easily manufactured component that can be readily replaced if needed, providing a cost-effective solution to the vacuum application problem
2Reliability
If the hole plug includes multiple features (nubs, grooves, bevel), then the bonding and debulking effectiveness improve, but the manufacturing complexity increases
Solution Approach 1:
The hole plug is divided into distinct functional segments: the bevel for adhesive application and mechanical interlocking, the nubs for frictional resistance and positioning, and the grooves for adhesive carrier channels, allowing each feature to be optimized independently
Solution Approach 2:
Different regions of the hole plug have different properties: the bevel provides a tapered entry, the nubs provide localized friction points, and the grooves provide adhesive pathways, with each region optimized for its specific function
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 hole plug simplifies the repair process by maintaining the repair patch in place during curing, ensuring a strong mechanical bond and effective debulking of excess resin, thereby enhancing the integrity of the composite structure.
Implementation Method 1
providing additional adhesive carriers and frictional resistance
Implementation Method 2
a vacuum force is applied to the fiber patch during the resin cure to compact the two or more fiber layers that make up the fiber patch by removing air and volatile gases from within and between the laminated layers
Implementation Method 3
applying an adhesive to a plurality of grooves defined by a shank of a hole plug, fully inserting the hole plug into the hole
Data Source
AI summary
A hole plug that can be used during rework or repair of a composite fiber assembly includes various features that allow placement of a vacuum force to the surface being reworked or repaired. In some implementations, the hole plug can include a plurality of nubs positioned around a shank. The nubs can secure the hole plug to the composite fiber assembly until a cure of an adhesive. The hole plug can further include a plurality of longitudinally oriented grooves extending along the shank and positioned between the plurality of nubs, and can include a notch positioned circumferentially around the shank. The grooves and notch can be used as adhesive carriers that assist with dispersal of a sufficient volume of the adhesive onto other portions of the shank and the composite fiber assembly during insertion of the hole plug into a hole in the composite fiber assembly.