Perforated Metallic Foil Composite Panel for Lightning Protection
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Solution Overview
Problem
Current composite panels used in aerospace structures are susceptible to damage from lightning strikes due to their poor conductivity, and existing solutions like expanded metallic foils are heavy and costly, limiting the ability to reduce aircraft weight while maintaining required electrical withstand capabilities.
Innovation Solution
A composite panel design incorporating a thin perforated metallic foil with optimized apertures and a protective resin layer, which reduces weight and improves conductivity, allowing for lighter aircraft while meeting lightning strike protection requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expanded metallic foils are used for lightning strike protection, then electrical conductivity is improved, but weight increases
Solution Approach 1:
The patent employs a perforated metallic foil with a porous structure featuring apertures distributed across its surface. This porous design reduces the material quantity and overall weight while preserving sufficient electrical conductivity pathways for lightning strike protection. The optimized aperture distribution ensures that the foil maintains adequate conductivity despite the reduced material density.
Solution Approach 2:
The invention integrates a perforated metallic foil with composite panel materials to create a hybrid structure. This composite approach combines the lightweight benefits of composite materials with the electrical conductivity of metallic foil, achieving both weight reduction and lightning strike protection capability. The perforated foil acts as a conductive network within the composite panel structure.
2Reliability
If expanded metallic foils are used for lightning strike protection, then electrical conductivity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies optimized parameters for the perforated metallic foil including aperture size, aperture distribution pattern, and foil thickness. By carefully controlling these parameters, the design achieves the required electrical conductivity while simplifying the manufacturing process. The standardized parameter specifications enable consistent production without requiring complex manufacturing procedures.
3Weight of moving object
If thinner metallic foils are used to reduce weight, then weight decreases, but resistance to erosion and peeling worsens
Solution Approach 1:
The patent combines the thin perforated metallic foil with composite panel materials and adhesive layers to create a reinforced composite structure. This composite construction provides mechanical support and protection to the thin foil, enhancing its resistance to erosion and peeling while maintaining the weight reduction benefits. The multi-layer composite structure distributes mechanical stresses away from the thin conductive foil.
Solution Approach 2:
The invention applies different material properties and thicknesses at different locations within the protective system. The perforated foil may have varying aperture patterns or thickness in different regions to optimize both weight and local strength requirements. Critical areas with higher erosion risk may receive enhanced protective measures while less critical areas maintain minimal thickness for weight savings.
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 perforated metallic foil design achieves a significant reduction in weight-to-conductivity ratio, enabling the production of lighter, more efficient aircraft that can withstand high-amplitude lightning strikes with minimal peeling and erosion resistance.
Implementation Method 1
Aircraft manufacturers have used aluminum or copper expanded foils or woven wire mesh incorporated into these composite panels to dissipate lightning strike energy
Data Source
AI summary
A composite panel having a plurality of carbon plies, a perforated metallic foil comprising several apertures and being directly secured to the plurality of carbon plies, and a protective layer made from resin reinforced with fibers which is secured to the metallic foil. The perforated metallic foil is embedded in the protective layer through its apertures. A free surface of the protective layer forms a top side of the composite panel. The thickness of the protective layer between the top side of the composite panel and the perforated metallic foil is at least 15 micrometers and the perforated metallic foil has a thickness of not more than 30 micrometers. The plurality of apertures in the aggregate defines an open area of not more than 40% of the surface area and a maximum distance between two opposed points in a perimeter of an aperture is equal to or less than 3 mm.