Conductive Adhering Layer for Composite Fastener Electrical Conduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modern aircraft using composite materials like carbon fiber-reinforced polymers (CFRPs) face challenges in electrical conduction, leading to arcing and sparking issues due to poor conductivity, and existing solutions such as sleeved fasteners and liquid metals are costly and mechanically detrimental.
Innovation Solution
A method involving an adhering layer of electrically conductive ink or paint with copper or silver particles, including low-temperature sintering agents, applied to composite bodies using screen-printing or ink-jet printing, which promotes electrical conduction between metallic components and CFRPs without damaging the composite structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If clearance-fit fasteners are used with composite materials, then ease of manufacture is improved, but electrical conduction deteriorates resulting in arcs and sparks
Solution Approach 1:
An adhering layer comprising electrically conductive material is applied as an intermediary between the clearance-fit fastener and the composite material hole. This layer fills the clearance gap and provides the necessary electrical conduction path without requiring interference-fit fasteners or complex sleeved fastener assemblies.
Solution Approach 2:
The electrical conductivity parameter is enhanced by introducing conductive material in the adhering layer. The conductive material can be applied in various forms (paint, ink, coating) and cured to achieve the desired conductivity level, transforming the non-conductive clearance gap into a conductive path.
2Reliability
If liquid metals are used to fill the space between fastener and composite hole, then electrical conduction is improved, but mechanical properties deteriorate due to brittle intermetallic compounds
Solution Approach 1:
Instead of using liquid metals that form brittle intermetallic compounds, the invention uses conductive materials with appropriate melting points and chemical compatibility. The adhering layer material is selected to avoid intermetallic formation while maintaining electrical conductivity, such as conductive paints, inks, or coatings that cure without reacting detrimentally with titanium or other structural metals.
Solution Approach 2:
The invention replaces expensive and mechanically detrimental liquid metal solutions with more affordable and mechanically compatible conductive materials. The adhering layer uses conductive paints or inks that are cost-effective and do not compromise the mechanical integrity of the fastener or composite structure.
3Reliability
If conductive paints with particles are used to improve electrical conductivity, then electrical conduction is enhanced, but application difficulty increases and conductivity remains modest
Solution Approach 1:
The invention optimizes the conductive material formulation and application parameters to achieve high conductivity with easier application. The adhering layer uses conductive paints or inks with improved particle distribution, viscosity control, and curing characteristics that enhance conductivity while simplifying the application process.
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 effective electrical conductivity at fastened joints, enhancing lightning protection and electromagnetic effects management systems while maintaining the structural integrity and cost-effectiveness of composite materials.
Implementation Method 1
promotes electrical conduction between metallic components and composite materials
Implementation Method 2
low-temperature sintering agents
Implementation Method 3
applied to composite bodies using screen-printing or ink-jet printing
Implementation Method 4
applied to composite bodies using screen-printing or ink-jet printing
Implementation Method 5
The adhering layer is selectively deposited inside the hole in the composite body, and/or along an edge of the hole in the composite body, and/or on at least a portion of a surface of the composite body
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for promoting electrical conduction between metallic components and composite materials. A composite body is coated with an adhering layer comprising a conductive material, and a metallic component is electrically connected to the conductive material of the adhering layer, when the metallic component is coupled to the composite body. The adhering layer is deposited inside a hole in the composite body, and/or along an edge of the hole, and/or on at least a portion of a surface of the composite body. The composite body is a structure of an aircraft or other vehicle comprised of composite materials formed from carbon fiber-reinforced polymers (CFRPs), the metallic component is a fastener or is positioned at an interface between the fastener and the composite body, and the electrical connection is made as part of a lightning protection system, an electromagnetic effects (EME) management system, or grounding system.