Conductive Bonded Joints for Lightning Strike Resilience
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Solution Overview
Problem
Fibre reinforced polymer composite structures face challenges in forming resilient bonded joints that can withstand lightning strikes, particularly in maintaining conductivity and structural integrity under high energy density conditions.
Innovation Solution
A method involving a conductive adhesive composition with high loadings of conductively coated nano-scale particulate fillers, such as carbon nanotubes, combined with a conductive intermediary structure, is used to create a bonded joint between two fibre reinforced polymer composite surfaces, ensuring conductivity and enhanced mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bonding methods are used on fibre reinforced polymer composite structures, then bonding simplicity is maintained, but the bonded joint cannot withstand lightning strikes and lacks conductivity
Solution Approach 1:
The patent uses a conductive adhesive composition containing high loadings (1-40% by weight) of conductive particulate fillers such as carbon nanotubes, graphene platelets, or metal-coated particles combined with a curable binder. This composite adhesive material provides both bonding functionality and electrical conductivity, enabling the bonded joint to withstand lightning strikes while maintaining structural integrity.
Solution Approach 2:
The conductive adhesive acts as an intermediary material between the fibre reinforced polymer composite substrates, providing a conductive pathway for lightning energy dissipation. The adhesive composition includes conductive fillers that create percolation networks within the binder matrix, mediating the electrical and mechanical properties between the bonded surfaces.
2Reliability
If high energy density conditions are applied to test bonded joints, then conductivity and structural integrity can be evaluated, but conventional bonds fail under these conditions
Solution Approach 1:
The conductive adhesive composition converts the harmful lightning strike energy into a manageable electrical current that can be dissipated through the bonded joint. The high loading of conductive fillers creates multiple parallel conduction pathways that safely channel the high energy density lightning current, preventing thermal runaway and structural failure.
Solution Approach 2:
The patent changes the electrical conductivity parameter of the bonding material by incorporating high concentrations of conductive particulate fillers. This parameter change transforms the adhesive from an electrical insulator to a conductor, enabling the joint to handle lightning strike energy densities that would otherwise cause catastrophic failure.
3Reliability
If conductive fillers are added to adhesive composition, then conductivity is improved, but manufacturing complexity and processing difficulty increase
Solution Approach 1:
The conductive fillers are distributed non-uniformly within the adhesive composition, with higher concentrations at the filler loading levels specified (1-40% by weight). This local concentration creates percolation networks that provide conductivity pathways where needed, while the curable binder maintains the adhesive's processability and bonding properties in other regions.
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 solution provides a lightning strike resilient bonded joint with improved conductivity, thermal properties, and structural durability, enabling effective energy dissipation and protection against electromagnetic hazards.
Implementation Method 1
The conductive adhesive composition with high loadings of conductively coated nano-scale particulate fillers provides lightning strike resilience through effective energy dissipation
Implementation Method 2
The particulate filler comprises a conductive coating, preferably a metal coating such as nickel, silver or copper
Implementation Method 3
curing the conductive adhesive to form a bonded first and second surface
Data Source
AI summary
The invention relates to methods of bonding and a conductively bonded joint, provided by high loadings of conductively coated nano scale particulate fillers in a conductive adhesive in combination with a conductive intermediary structure, more particularly to a lightning strike resilient bonded joint between fibre reinforced polymer composites.A method of joining a first fibre reinforced polymer composite surface and a second fibre reinforced polymer composite surface, comprising the steps ofproviding a conductive intermediary structure between said first and second surfaces,filling the void between said surfaces and enveloping said intermediary structure with a conductive adhesive,curing the conductive adhesive to form a bonded first and second surface.A conductive adhesive comprising a curable binder and a high aspect ratio nanoscale carbon particulate filler present in the range of from 0.1 to 40% wt, wherein said particulate filler comprises a metal coating.