Conductive Composite Interlaminar Regions for Lightning Protection
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Solution Overview
Problem
Fiber-reinforced polymer composites used in aerospace applications face challenges with low electrical conductivity due to the dielectric nature of matrix resins, leading to issues like edge glow during lightning strikes, which can ignite fuel vapors and pose safety risks.
Innovation Solution
Incorporating polymeric toughening particles and carbon-based nanostructures into the interlaminar regions of composite materials to enhance z-direction electrical conductivity while maintaining mechanical properties, such as impact resistance and delamination toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional fiber-reinforced polymer composites are used, then mechanical properties such as strength-to-weight ratio and fatigue endurance are improved, but electrical conductivity deteriorates due to the dielectric nature of matrix resins
Solution Approach 1:
The patent applies composite materials by combining carbon fibers with graphitic coatings and conductive resin systems to create a multi-phase composite structure. The graphitic coating on carbon fibers and the conductive resin matrix work synergistically to achieve both mechanical strength and electrical conductivity, resolving the contradiction between structural performance and electrical functionality.
Solution Approach 2:
The patent applies local quality by creating regions of enhanced electrical conductivity at specific locations within the composite structure, particularly at the interlaminar regions and fiber-matrix interfaces. The graphitic coating is applied locally on carbon fibers to create conductive pathways without compromising the overall mechanical properties of the composite structure.
2Reliability
If z-direction electrical conductivity is increased to prevent edge glow, then lightning strike protection is improved, but delamination resistance and impact strength may deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the electrical conductivity parameter of the resin matrix through the addition of conductive fillers and graphitic components. This changes the electrical properties of the composite without fundamentally altering the mechanical structure, allowing improved lightning protection while maintaining delamination resistance through proper formulation of the conductive resin system.
3Object-affected harmful factors
If sealants are applied at fuel tank edges to prevent edge glow, then safety is improved, but device complexity and weight increase
Solution Approach 1:
The patent applies the taking out principle by removing the need for separate sealant applications through the integration of edge glow protection directly into the composite material structure itself. The conductive composite layers and interlaminar regions provide inherent protection against edge glow, eliminating the need for additional sealant components and their associated application complexities.
Solution Approach 2:
The patent applies universality by designing the composite material structure to perform multiple functions simultaneously: structural support, electrical conductivity for lightning protection, and edge glow prevention. The same composite layers that provide mechanical strength also provide electrical pathways that prevent edge glow, eliminating the need for separate protective measures.
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 composite materials exhibit improved z-direction electrical conductivity, reduced risk of edge glow, and enhanced mechanical performance, including Compression Strength After Impact (CAI) and fracture toughness, effectively mitigating lightning strike effects and providing electromagnetic shielding.
Implementation Method 1
carbon-based, nano-sized structures at the interlaminar region between adjacent layers of reinforcement fibers... enhance z-direction electrical conductivity
Implementation Method 2
polymeric toughening particles... at the interlaminar region between adjacent layers of reinforcement fibers... enhanced mechanical performance, including Compression Strength After Impact (CAI) and fracture toughness
Data Source
AI summary
A curable composite material that may be used in applications where both high mechanical performance and high electrical conductivity are required. The curable composite material includes two or more layers of reinforcement fibers that have been infused or impregnated with a curable matrix resin and an interlaminar region containing carbon nanomaterials, e.g. carbon nanotubes, and insoluble polymeric toughening particles. The carbon nanomaterials are significantly smaller in size as compared to the polymeric toughening particles. The polymeric toughening particles are substantially insoluble in the matrix resin upon curing of the composite material, and remain as discreet particles at the interlaminar region after curing. Methods for fabricating curable composite materials and cured composite structures are also disclosed.