Composite Aircraft Wing Fuel Tank Access Cover Design
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Solution Overview
Problem
Existing aircraft wing fuel tank access covers face issues with galvanic corrosion, weight, shock resistance, and aerodynamic efficiency due to single-layer metal structures, which are difficult to address simultaneously.
Innovation Solution
A composite access cover design featuring a titanium or aluminum alloy outer cover, a composite honeycomb or foam sandwich inner cover, and an adhesive rivetless floating anchor self-locking nut, with a sealing strip embedded between the wing lower panel and inner access cover, providing improved rigidity, weight reduction, and enhanced sealing while avoiding galvanic corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-layer aluminum alloy access cover is used, then the structure is simple and easy to manufacture, but galvanic corrosion occurs and weight reduction is limited
Solution Approach 1:
The patent applies composite materials by combining an inner access cover made of composite materials (carbon fiber reinforced plastic or other non-metallic materials) with an outer access cover made of aluminum alloy. This composite structure eliminates galvanic corrosion between dissimilar metals while maintaining manufacturability, as each layer can be manufactured separately using appropriate processes for its material type.
Solution Approach 2:
The access cover is segmented into two distinct layers: an inner access cover and an outer access cover. The inner layer provides corrosion resistance and weight reduction, while the outer layer provides structural integrity and sealing. This segmentation allows each layer to be optimized for its specific function and manufactured independently.
2Device complexity
If a single-layer aluminum alloy access cover is used, then the structure is simple, but weight reduction is insufficient and shock resistance is compromised
Solution Approach 1:
The inner access cover is made of composite materials such as carbon fiber reinforced plastic, which have superior strength-to-weight ratios compared to solid aluminum alloy. This composite construction significantly reduces the overall weight of the access cover assembly while maintaining structural integrity through the layered design.
Solution Approach 2:
The inner access cover can be designed as a thin-walled composite structure that provides sufficient strength through material composition rather than thickness. The composite materials offer high specific strength, allowing thin-walled construction that reduces weight while maintaining load-bearing capacity.
3Ease of manufacture
If a single-layer aluminum alloy access cover is used, then manufacturing is straightforward, but shock resistance and aerodynamic efficiency are insufficient
Solution Approach 1:
The composite material inner access cover provides excellent shock absorption and resistance due to the energy-absorbing properties of composite materials. The layered structure with the inner composite layer and outer aluminum alloy layer creates a progressive failure mode that enhances overall shock resistance while maintaining manufacturing feasibility through separate layer production.
Solution Approach 2:
The segmented two-layer structure allows the inner layer to be optimized for shock absorption and the outer layer for structural integrity and sealing. This segmentation enables each layer to be manufactured using processes optimized for its specific requirements, with the inner layer providing shock resistance and the outer layer providing mechanical strength.
4Device complexity
If a single-layer aluminum alloy access cover is used, then the structure is simple, but sealing reliability and detachment functionality are compromised
Solution Approach 1:
The access cover is divided into inner and outer layers that can be independently manufactured and assembled. This segmentation allows for the incorporation of specialized sealing elements and detachment mechanisms in the inner layer, while the outer layer provides structural support. The separate layers can be optimized for sealing and detachment functions without compromising overall structural simplicity.
Data Source
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AI summary
The present invention provides an aircraft wing fuel tank filler cap and a structure in a circumferential region of the filler cap and relates to the technical field of aviation. The aircraft wing fuel tank filler cap comprises an inner filler cap, an outer filler cap, a sandwich layer, a fixing piece and a fastener; the inner filler cap is hermetically connected to a wing lower panel and the outer filler cap through the sandwich layer; the fastener is disposed in the inner filler cap; the fixing piece passes through a fixing hole in the outer filler cap and is connected with the fastener; and an intercalation sunken region at filler cap of wing lower panel provides a flat mounting region for the inner filler cap and also guarantees fitting of the outer filler cap and the panel. The metal outer filler cap in the present invention guarantees the demands on the shock resistance and lightning protection of the fuel tank filler cap and plays a role in protecting the composite inner filler cap, and meanwhile, the composite inner filler cap is capable of effectively reducing the weight of a fuel tank filler cap assembly, so that galvanic corrosion brought by a single metal alloy filler cap is avoided.