Shape-Memory Fastener Cap for Lightning Ignition Suppression
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Solution Overview
Problem
Existing technologies for lightning protection of fastener stacks often require changes to the fastener stack or adhesive bonds, which can be cumbersome and may not effectively suppress or quench ignition.
Innovation Solution
The use of a device attachable to a fastener stack, comprising an attachment element made of shape memory material and a cap with a base and shell, where the attachment element is coupled to the cap to create a radially compressive load that secures the device over the fastener stack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing technologies for lightning protection are used, then lightning protection is provided, but the fastener stack requires changes or adhesive bonds which are cumbersome
Solution Approach 1:
The ignition suppression device is segmented into separate functional components: a cap that attaches to the fastener stack and a suppression element that contains the ignition suppression mechanism. This allows the device to provide protection without requiring modifications to the fastener stack itself, resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The device introduces an intermediary attachment mechanism that connects the suppression cap to the fastener stack without requiring permanent modifications or adhesive bonds. This intermediary solution provides reliable protection while avoiding the complexity of modifying the fastener stack structure.
2Strength
If adhesive bonds are used for attachment, then the device can be secured, but the installation becomes cumbersome
Solution Approach 1:
The device replaces adhesive bonding (chemical attachment) with a mechanical attachment system using the cap and attachment element. This mechanical system provides equivalent or superior attachment strength while dramatically simplifying the installation process, eliminating the need for adhesives and associated curing times.
3Reliability
If the device securely attaches to the fastener stack, then ignition is suppressed, but the attachment mechanism adds complexity
Solution Approach 1:
The attachment element is designed to automatically secure the cap to the fastener stack through its own structural features without requiring additional fasteners, adhesives, or complex assembly steps. This self-service attachment mechanism provides reliable ignition suppression while minimizing added complexity.
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 effectively suppresses or quenches ignition by securely attaching an ignition suppression or quenching device to the fastener stack, preventing electrical discharges from igniting flammable materials.
Implementation Method 1
a stimulus is applied that is sufficient to cause the shape memory material in place to transform to a second shape
Implementation Method 2
the attachment element is coupled to the cap to create a radially compressive load that secures the device over the fastener stack
Data Source
AI summary
A device which is attachable to a fastener stack, the device comprising: an attachment element made of shape memory material; and a cap comprising a base having an aperture and a shell having an interior space in fluid communication with the opening, wherein the base supports the shell and is coupled to the attachment element.