Vented Fastener Cap Structure for Aircraft Fuel Tank Ignition Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft fasteners pose an ignition risk during lightning strikes due to electrical currents passing through composite materials, which can generate electromagnetic effects that interact with combustible fuel vapors, and existing polysulfide cap seals are labor-intensive to install and maintain, increasing production and inspection time.
Innovation Solution
A cover with a base and cap configuration that includes holes with specific hydraulic diameters to vent gas and particles, preventing a line of sight from the exterior environment to the fastener and isolating it within an interior space to prevent ignition, while allowing for easy installation and alignment to shield the fastener from potential ignition sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polysulfide cap seals are used to seal fuel mixtures from arcs and hot particles, then ignition risk is reduced, but installation time and inspection time increase
Solution Approach 1:
The patent extracts the sealing function from the cap structure by incorporating holes through the cap, eliminating the need for traditional polysulfide sealant application. The holes themselves serve as the sealing mechanism through their geometric configuration, removing the labor-intensive sealing step while maintaining ignition protection.
Solution Approach 2:
The cap structure with integrated holes provides self-sealing functionality through its design. The holes are configured to prevent line-of-sight trajectories from the exterior to the fastener, creating a self-contained protective barrier that does not require additional sealing materials or complex installation procedures.
2Reliability
If traditional cap seals are used to prevent fuel contact with fasteners, then ignition prevention is achieved, but manufacturing complexity increases
Solution Approach 1:
The cap is designed with discrete holes rather than requiring continuous sealant application. This porous approach simplifies the manufacturing process by eliminating sealant mixing, application, and curing steps, while the specific hole configuration (hydraulic diameter 0.5-2.0mm) maintains the protective function by blocking ignition trajectories.
3Temperature
If holes are added to the cap to vent gas and particles, then thermal and kinetic energy are reduced, but seal integrity becomes more difficult to maintain
Solution Approach 1:
The patent converts the potential harm of trapped hot gas and particles into a benefit by designing controlled venting holes. These holes allow thermal and kinetic energy to escape in a controlled manner, preventing pressure buildup and maintaining cap integrity, while the hole configuration ensures no direct line-of-sight to the fastener exists.
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 cover effectively prevents ignition by venting thermal and kinetic energy, reducing the risk of fuel tank ignition and simplifying the installation process by providing a resilient, airtight seal that reduces production and inspection time.
Implementation Method 1
The cover effectively prevents ignition by venting thermal and kinetic energy
Implementation Method 2
The cover effectively prevents ignition by venting thermal and kinetic energy
Implementation Method 3
Each of the holes includes a hydraulic diameter of between 0.1 mm-2.0 mm
Data Source
AI summary
A cover that extends over a fastener and methods of installing the cover over the fastener. The cover includes an open end positioned at a member from which the fastener extends. The cover also includes a closed end that extends over the fastener and shields the fastener from the exterior environment that can be combustible. A plurality of holes extend through the cover from the interior space to an exterior environment external to the cap.