Composite Clamp Ring for Aircraft Door Lightning Protection
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Solution Overview
Problem
Aircraft airframes made of composite materials like carbon fiber face challenges in lightning protection, as direct strikes can generate arc discharges due to poor current diffusion, and traditional metal solutions like titanium alloys are expensive and heavy.
Innovation Solution
A closing member for aircraft openings, comprising a carbon fiber composite clamp ring and a titanium alloy or stainless alloy door body, with tapered surfaces for secure electrical bonding, allowing current to dissipate safely through the carbon fiber, reducing weight and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metal materials like titanium alloy are used for the closing member to establish electrical bonding, then lightning protection capability is improved, but weight and material cost increase
Solution Approach 1:
The clamp member is constructed using carbon fiber composite material that provides both structural function and electrical conductivity for lightning protection. The carbon fiber reinforcement bars embedded in the resin matrix create conductive pathways while maintaining lightweight properties, resolving the contradiction between needing metal for electrical bonding and wanting to reduce weight.
Solution Approach 2:
The closing member uses a hybrid structure where only specific components (clamp member and reinforcement bars) are made of conductive carbon fiber composite material to provide electrical bonding, while other parts can use lighter non-conductive materials. This localized application of conductive material achieves lightning protection without making the entire closing member heavy.
2Reliability
If traditional metal materials like titanium alloy are used for the closing member to establish electrical bonding, then lightning protection capability is improved, but material cost increases
Solution Approach 1:
The invention replaces expensive titanium alloy with carbon fiber composite material that provides equivalent electrical conductivity and structural performance. The carbon fiber reinforcement bars create conductive pathways within the composite clamp member, achieving lightning protection at lower material cost while maintaining manufacturing feasibility.
3Weight of moving object
If carbon fiber composite material is used for the clamp member, then weight and material cost are reduced, but electrical bonding capability is compromised
Solution Approach 1:
The clamp member uses carbon fiber reinforced composite material where the carbon fiber reinforcement bars provide electrical conductivity pathways within the resin matrix. This composite structure maintains the lightweight advantage of carbon fiber while restoring the electrical bonding capability needed for lightning protection, overcoming the limitation of pure composite materials.
Solution Approach 2:
The carbon fiber reinforcement bars are strategically positioned within the clamp member to create conductive pathways at critical contact points with the wing panel. This localized concentration of conductive material ensures effective electrical bonding for lightning current dissipation while minimizing the overall material usage and maintaining lightweight properties.
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 lightning protection by ensuring electrical bonding between the closing member and the airframe panel, preventing arc discharges and reducing weight and material costs.
Implementation Method 1
A small amount of current is passed through the composite material including the carbon fiber. In order to prevent electric isolation of the access door it is necessary to establish electrical bonding between the access door and the wing panel
Implementation Method 2
the closing member body and an inner circumferential portion of the clamp member abut on each other, and the outer circumferential portion of the clamp member and an inner edge portion of the opening abut on each other, whereby the closing member is electrically connected to the panel through the clamp member
Data Source
AI summary
An object of the invention is to provide a low-cost closing member for an opening having an excellent lightning protection capability.A door body 30, a clamp ring 40 made of a composite material, and an opening 12 of a wing panel 11 made of the composite material are electrically connected by surface bonding of conductive materials in a butt section of an abutment surface 34 of the door body 30 and a tapered surface 40c of the clamp ring 40 and a butt section of a tapered surface 40d of the clamp ring 40 and an abutment surface 14 of the opening 12.