Composite Fiber Contact Points for Lightning Strike Current Distribution
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Solution Overview
Problem
Composite materials used in aircraft components, such as CFRP, face issues with high local electric current density and subsequent temperature rise due to insulation properties, leading to potential short-circuits and damage from lightning strikes, as the resin between carbon fiber layers electrically insulates them, causing uneven current distribution.
Innovation Solution
A manufacturing method involving superimposed layers of electrically conductive fibers embedded in an insulating matrix, where a superficial pressure is applied during vacuum compression and cooking to create permanent contacts between fiber layers, allowing electric current to flow along the fibers and reducing local current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If superimposed layers of electrically conductive fibers are embedded into an electrically insulating matrix, then mechanical strength and corrosion resistance are improved, but electrical insulation between layers increases causing high local current density
Solution Approach 1:
The patent applies local quality by creating selective electrical contact points between fiber layers at specific locations where cables contact the component, while maintaining electrical insulation in other areas. This is achieved through controlled deformation during manufacturing that brings fibers into contact only at designated spots, allowing current to distribute laterally across multiple layers locally rather than concentrating vertically at cable contact points.
Solution Approach 2:
The patent transitions the electrical current path from a primarily vertical one-dimensional flow through insulating resin between layers to a multi-dimensional path that spreads laterally across fiber layers. By creating contact points that enable current to flow horizontally along conductive fibers before moving to the next layer, the current distribution becomes two-dimensional, reducing concentration at any single point.
2Stability of the object's composition
If resin between carbon fiber layers electrically insulates the layers, then structural integrity is maintained, but high local density of electric current is created at cable contact level causing temperature increase
Solution Approach 1:
The patent introduces conductive fiber contact points as intermediary pathways between cable and component interior. These fiber-to-fiber contact points act as mediator channels that distribute electrical current laterally across multiple layers before it penetrates deeper, preventing direct vertical current concentration through the insulating resin and thereby reducing Joule heating at the cable contact interface.
3Reliability
If superficial pressure is exerted on the assembly during cooking to generate deformation causing local fiber contacts, then electrical conductivity between layers is improved, but fiber damage risk increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the magnitude, duration, and timing of superficial pressure applied during the cooking process. The pressure is sufficient to deform the assembly and bring fibers into contact, but controlled to remain below the threshold that would damage fiber strength. This optimized pressure parameter creates the necessary electrical contact while preserving mechanical integrity.
Solution Approach 2:
The patent applies preliminary action by pre-positioning the assembly in a specific configuration before applying pressure, and by applying the pressure during the cooking process when the resin is in a favorable state for deformation. This preliminary preparation ensures that when pressure is applied, the assembly deforms in a controlled manner that creates fiber contacts without causing damage, as the resin matrix is more compliant during cooking.
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
This method reduces heating at the point of electric current application by facilitating current flow through the fibers, minimizing temperature increases during short-circuits and lightning strikes, while maintaining the mechanical properties of the composite material.
Implementation Method 1
the resin between the carbon fiber layers, forming the matrix of the composite material, electrically insulates those layers one from the others
Implementation Method 2
a superficial pressure is exerted on said assembly generating a deformation that causes local contacts of fibers of at least two superimposed layers
Implementation Method 3
such electric contacts allow electric current to flow following the fibers of the thus contacted different layers
Implementation Method 4
a vacuum is achieved around this assembly; and this assembly is submitted in vacuo to a compression and a cooking
Data Source
AI summary
During the cooking of a composite component including layers of fibers embedded into a matrix, a superficial pressure is exerted. This superficial pressure generates a deformation that causes local contacts of fibers of at least two layers without damaging these fibers. As a result, when an electrical current is applied on a side of the composite component, such as during a lightning strike or a short circuit, the added local contacts enable the electric current to flow along multiple fibers in the composite component, thereby avoiding significant spikes in temperature.