Lightning Diverter Overlay with Dielectric Spacing
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Solution Overview
Problem
Current lightning protection systems for aircraft are costly, prone to cracking due to thermal expansion differences, and may cause damage to composite structures, while also failing to effectively mitigate static charging and provide adequate protection against lightning strikes, especially in areas with fasteners and complex curvatures.
Innovation Solution
A low-cost appliqué system featuring a metal foil spaced apart from the substrate by a dielectric layer, which disperses lightning energy over a wide area and includes patterned metal foils to divert energy away from critical structures, thereby reducing damage and static charge buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metal mesh or foil is used for lightning protection, then lightning strike protection is provided, but cracking occurs due to thermal expansion differences between metal and composite substrate
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the metal foil and composite substrate. This dielectric layer has matched thermal expansion properties that prevent cracking while allowing the metal foil to provide lightning protection. The dielectric layer mediates the thermal expansion mismatch between the metal and composite materials.
Solution Approach 2:
The lightning protection system uses a composite structure consisting of metal foil combined with dielectric material. This composite construction combines the electrical conductivity of metal with the thermal expansion compatibility of dielectric materials, achieving both lightning protection and cracking resistance.
2Reliability
If metal foil is placed directly on the substrate, then lightning protection is achieved, but static charging is not effectively mitigated
Solution Approach 1:
The dielectric layer serves as an intermediary that enables static charge mitigation while maintaining lightning protection. It allows the metal foil to discharge static charges safely without direct contact with the substrate, preventing charge buildup that would occur with direct metal-to-substrate contact.
3Manufacturing precision
If conventional painting process is used, then surface coating is achieved, but environmental impact increases due to volatile solvents
Solution Approach 1:
The harmful volatile solvents and environmental pollutants are extracted and removed from the coating process. The invention uses a dielectric layer-based coating system that achieves surface coating functionality without requiring traditional paint solvents, eliminating the environmental harm while maintaining coating quality.
4Manufacturing precision
If painting process is used for surface coating, then uniform coating is achieved, but cost and time increase due to specialized facilities
Solution Approach 1:
The invention replaces expensive, complex painting facilities with a simpler, more economical dielectric layer coating system. The dielectric layer can be applied using less complex equipment and processes, reducing facility requirements and costs while achieving the necessary coating uniformity for protection.
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 appliqué system provides enhanced lightning strike protection, reduces the risk of cracking, and mitigates static charging, while being cost-effective and adaptable to complex surface curvatures, thus improving the durability and safety of aircraft surfaces.
Implementation Method 1
a metal foil spaced apart from the substrate by a dielectric layer, which disperses lightning energy over a wide area
Implementation Method 2
includes patterned metal foils to divert energy away from critical structures
Data Source
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Figure 5~6
AI summary
An overlay of patterned metal foil above a substrate to be protected supports development of localized coronas after a lightning strike. The localized coronas transport energy of a lightning strike above the substrate's surface with limited removal of metal foil from the lightning strike attachment point. A first polymer film underlies patterned metal foil. A topcoat overlies the patterned metal foil. An adhesive, underlying the first polymer film affixes the lightning diverter overlay to the substrate. If desired, semiconductor particulates may be dispersed throughout the second polymer film to contribute to instantaneous generation of localized coronas. Also, an ink layer may be provided between the patterned metal foil and the topcoat or on the exterior, if desired, for aesthetic and/or anti-static purposes.