Translucent Seal Cap Void Filling for Aircraft Fuel Cells
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Solution Overview
Problem
Traditional methods for sealing fasteners in aircraft fuel storage cells are inefficient in preventing corrosion, electrical discharge, and void formation, leading to potential ignition risks during lightning strikes, and are time-consuming and costly to repair.
Innovation Solution
The method involves applying a first quantity of uncured sealant to a fastener, followed by an optically translucent seal cap, curing the sealant, filling any voids within the seal cap with a second quantity of uncured sealant, and curing it, using actinic radiation or injection from a syringe, to ensure complete sealing and inspection visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal cap is applied over uncured sealant, then the sealant can be cured in place, but voids may form within the sealant that compromise sealing effectiveness
Solution Approach 1:
The seal cap is applied over the uncured sealant before curing occurs, creating a mold that defines the final sealant shape and prevents void formation during the curing process. This preliminary positioning ensures the sealant cures in the correct location without gaps or air pockets.
Solution Approach 2:
The optically translucent seal cap serves as an intermediary between the uncured sealant and the external environment, allowing visual inspection of the sealant while it cures and preventing void formation by confining the sealant within its boundaries during the curing process.
2Reliability
If traditional opaque seal caps are used, then sealing is achieved, but visual inspection of the sealant and detection of voids is impossible
Solution Approach 1:
The seal cap is made optically translucent instead of opaque, allowing light to pass through so that the sealant and any voids within it can be visually inspected. This transparency enables quality control personnel to detect voids, bubbles, or improper sealant application without opening or destroying the seal.
3Reliability
If high dielectric breakdown strength materials are used for the seal cap, then electrical discharge prevention is improved, but the material selection and manufacturing complexity increases
Solution Approach 1:
The seal cap is made from a composite material that combines high dielectric breakdown strength properties with optical translucency. This composite material simultaneously provides electrical discharge prevention and visual inspection capability, resolving the contradiction between electrical safety and detectability.
4Productivity
If rapid curing processes are used, then production time is reduced, but complete curing of thick sealant layers may be compromised
Solution Approach 1:
The curing process uses actinic radiation (light-based curing) instead of traditional thermal or chemical curing methods. This allows rapid curing of the sealant while ensuring complete penetration through the sealant layer, as the radiation can penetrate the optically translucent seal cap and cure the sealant uniformly without requiring thick sections to be heated or chemically activated slowly.
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 effectively seals fasteners, prevents electrical discharge, and allows for visual inspection and rapid repair of voids, enhancing safety and reducing production delays by using translucent materials with high dielectric breakdown strength and rapid curing processes.
Implementation Method 1
curing the first quantity of uncured sealant to form a first quantity of cured sealant; curing the second quantity of sealant is accomplished by application of actinic radiation to the sealant through the seal cap
Implementation Method 2
filling a void within the interior of the seal cap with a second quantity of uncured sealant is accomplished by injecting a second quantity of uncured sealant into the void from a syringe
Data Source
AI summary
Methods of using and repairing seal caps as well as constructions comprising seal caps, including in some embodiments seal caps which may be useful in sealing fasteners that protrude into fuel storage cells in aircraft. In some embodiments, methods include the use of optically translucent seal cap and application of a second quantity of sealant to fill voids observed within the interior of the seal cap after cure of a first quantity of sealant.