Conductive Pins for Lightning Protection in CFRP Aircraft Panels
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Solution Overview
Problem
Carbon Fiber Reinforced Plastic (CFRP) aircraft components have low conductivity, leading to high current concentration at fasteners during lightning strikes, potentially causing ignition hazards due to anisotropic conductivity.
Innovation Solution
Inserting electrically conductive pins through CFRP panels near fasteners to distribute current evenly and reduce concentration, thereby decreasing the probability of ignition hazards, and these pins can be fabricated within the panels to reduce weight and inserted automatically without additional cure time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If CFRP panels are used to construct aircraft components, then weight is reduced and strength is improved, but conductivity is insufficient leading to current concentration at fasteners
Solution Approach 1:
The patent integrates conductive pins made of electrically conductive material into the CFRP panel structure, creating a composite system that combines the lightweight properties of CFRP with the high conductivity of metal pins. This hybrid composite approach allows the structure to maintain low weight while achieving adequate lightning protection capability by distributing current through multiple pathways.
Solution Approach 2:
The patent places conductive pins at specific locations within the CFRP panel, particularly near fastener regions where current concentration is most problematic. This localized enhancement of conductivity addresses the specific weakness area without requiring the entire panel to be made of conductive material, thus maintaining weight efficiency while improving reliability at critical points.
2Reliability
If conductive pins are inserted through CFRP panels, then current distribution is improved and ignition hazards are reduced, but manufacturing complexity increases
Solution Approach 1:
The conductive pins are inserted into the CFRP panels during the manufacturing process, specifically during the autoclave curing cycle. This preliminary action ensures that the pins are already in place before the panel is assembled and installed, eliminating the need for separate post-manufacturing steps to add lightning protection features.
Solution Approach 2:
The patent combines the structural manufacturing process with the lightning protection feature integration by inserting conductive pins during the autoclave curing cycle. This merging of operations allows the pins to be positioned and secured simultaneously with the panel fabrication, reducing overall manufacturing complexity despite the additional functionality being added.
3Reliability
If conductive pins are added to CFRP panels, then lightning protection is improved, but production time increases due to additional cure time
Solution Approach 1:
The conductive pins are inserted into the CFRP panels during the manufacturing process, specifically during the autoclave curing cycle. This preliminary action ensures that the pins are already in place before the panel is assembled and installed, eliminating the need for separate post-manufacturing steps to add lightning protection features.
Solution Approach 2:
The patent combines the structural manufacturing process with the lightning protection feature integration by inserting conductive pins during the autoclave curing cycle. This merging of operations allows the pins to be positioned and secured simultaneously with the panel fabrication, reducing overall manufacturing complexity despite the additional functionality being added.
4Reliability
If conventional lightning mitigation techniques are used (polysulfide cap seal, edge sealant, conductive splice), then current concentration is reduced, but weight increases and manufacturing complexity increases
Solution Approach 1:
The patent integrates conductive pins made of electrically conductive material into the CFRP panel structure, creating a composite system that combines the lightweight properties of CFRP with the high conductivity of metal pins. This hybrid composite approach allows the structure to maintain low weight while achieving adequate lightning protection capability by distributing current through multiple pathways.
Solution Approach 2:
The patent places conductive pins at specific locations within the CFRP panel, particularly near fastener regions where current concentration is most problematic. This localized enhancement of conductivity addresses the specific weakness area without requiring the entire panel to be made of conductive material, thus maintaining weight efficiency while improving reliability at critical points.
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 conductive pins effectively spread current conduction away from fasteners, reducing the risk of damage and ignition hazards while maintaining structural integrity and streamlining manufacturing processes.
Implementation Method 1
Conductive pins are inserted through a CFRP panel to increase through-thickness conductivity near a fastener. In the event of a lightning strike, the pins distribute the current more evenly in the composite layers of the CFRP panel and spread through-thickness current conduction away from the fastener.
Data Source
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AI summary
The examples described herein provide for lightning protection in aircrafts constructed with Carbon Fiber Reinforced Plastic (CFRP). In one example, the apparatus includes a first Carbon Fiber Reinforced Plastic (CFRP) panel, a second CFRP panel that overlaps with the first CFRP panel in a vertical direction, and a fastener to join the first CFRP panel with the second CFRP panel, the fastener extending in the vertical direction in an area where the first CFRP panel and the second CFRP panel overlap. The apparatus further includes a plurality of electrically conductive pins in each of the first CFRP panel and the second CFRP panel, wherein the pins extend in the vertical direction proximate to the fastener to electrically connect the first CFRP panel and the second CFRP panel in the area where the first CFRP panel and the second CFRP panel overlap.