Composite Conductivity via Penetrative Spot Loads
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Solution Overview
Problem
Composite parts made with carbon fibers and thermosetting or thermoplastic materials have low transverse electrical conductivity, which is a concern for lightning dissipation and current return in aeronautical structures, as they lack significant conductivity orthogonal to their surface, and existing solutions like metal ribbons increase mass and cost.
Innovation Solution
The method involves penetrating carbon fibers through thermoplastic or thermosetting layers to enhance transverse electrical conductivity by creating controlled perforations, allowing carbon fibers to contact each other across layers, thereby increasing conductivity without the need for external metal inserts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal ribbons or braids are used to provide electrical conductivity in composite parts, then electrical conductivity is improved, but mass and cost increase
Solution Approach 1:
The carbon fiber reinforcement layers themselves provide the electrical conductivity function by creating conductive pathways through the resin layers. The structural carbon fibers serve dual purposes: mechanical reinforcement and electrical conduction, eliminating the need for separate metal conductivity elements.
Solution Approach 2:
The metal conductivity elements (ribbons, braids) are removed from the composite structure. Instead, the electrical conductivity function is extracted and assigned to the carbon fiber reinforcement layers, which naturally provide conductive pathways when properly oriented and connected across layers.
2Strength
If carbon fiber layers are stacked with resin layers to create composite parts, then mechanical properties are improved, but transverse electrical conductivity deteriorates
Solution Approach 1:
The resin layers are made locally conductive at specific points where carbon fibers penetrate through them. Instead of making the entire resin layer conductive, localized conductive pathways are created at penetration points, maintaining the insulating properties of the resin bulk while providing necessary conductivity paths.
Solution Approach 2:
The invention creates a multi-layer composite structure where carbon fiber layers and resin layers are combined. The carbon fibers provide both mechanical strength and electrical conductivity, while the resin provides structural integrity and protection. The composite achieves both mechanical performance and electrical conductivity through the synergistic combination of materials.
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 approach achieves transverse electrical conductivity of at least 15 S/m, preferably 20 S/m to 300 S/m, significantly improving the composite part's ability to dissipate electrical energy and ensure current return without increasing mass or cost.
Implementation Method 1
Carbon fiber conducts electricity unlike thermosetting or thermoplastic materials. The transverse electrical conductivity is therefore almost zero, due to the presence of resin layers. However, to dissipate the energy provided by the passage of lightning on the fuselage or the wing (wings) and also ensure the current return function, the transverse electrical conductivity of the composite parts used in aeronautics must be significant.
Data Source
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AI summary
Use, in the manufacture of a composite component made from a stack of reinforcing materials (R) of carbon fibres between which is interposed at least one layer of thermoplastic or thermoset material or of a mixture of thermoplastic and thermoset materials (CM), of an operation of applying penetrative spot loads to at least two layers that make up the stack and are positioned adjacent to one another in the stack, so as to pass in succession through at least one reinforcing material (R) and at least one layer of thermoplastic or thermoset material or of a mixture of thermoplastic and thermoset materials (CM) which are placed in superposed positions, in order to improve the transverse electric conductivity of the composite component obtained.