Composite Splice Design for Fuselage Section Joining
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Solution Overview
Problem
The high cost and time-consuming assembly process of titanium splices in aircraft fuselage sections due to the need for drilling and deburring, which increases labor and material costs, while also requiring expensive materials.
Innovation Solution
A splice design using a composite material strap, H-shaped fittings, and a shear tie with titanium fasteners, allowing for efficient bridging and connection of fuselage sections with reduced material and labor costs, and enabling faster assembly by using composite materials that facilitate quicker drilling and inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a titanium splice is used to join fuselage sections, then structural strength and reliability are improved, but material cost and assembly time increase significantly
Solution Approach 1:
The splice is divided into multiple functional components: a frame structure for bridging fuselage sections, through fittings for connection, and a composite material construction that segments the monolithic titanium approach into modular elements that can be assembled more efficiently
Solution Approach 2:
The patent employs composite materials (such as carbon fiber reinforced polymers) to replace titanium in the splice construction, maintaining structural strength while reducing weight and assembly complexity. The composite materials allow for integrated manufacturing of splice components, reducing the number of fasteners and drilling operations required
2Strength
If titanium material is used for the splice, then structural strength is maintained, but material cost increases
Solution Approach 1:
Composite materials such as carbon fiber reinforced polymers are used to replace titanium, providing comparable or superior strength-to-weight ratios at lower material cost. The composite construction allows for optimized fiber orientation to match stress patterns, maintaining structural integrity while reducing material expenses
Solution Approach 2:
The material parameters are changed from metallic titanium to composite materials with different mechanical properties. This substitution maintains the required strength levels while significantly reducing material cost, as composites can be manufactured more economically and offer superior specific strength
3Reliability
If multiple fasteners are used to attach the splice, then connection reliability is improved, but the number of drilling operations and labor cost increase
Solution Approach 1:
Multiple fastener functions are merged into integrated connection systems. The through fittings are designed to combine multiple attachment points into unified components, and the composite construction allows for fewer, larger fasteners that reduce the total number of drilling operations while maintaining connection reliability
Data Source
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AI summary
A splice (28) and an associated method are provided in order to efficiently join structures, such as adjacent fuselage sections (12). A splice for joining fuselage sections may include a strap ( 30 ) configured to bridge the fuselage sections, a shear tie (38) overlying the strap and a fitting (32) positioned between the strap and the shear tie such that the strap and the shear tie are spaced apart. At least the strap and the fitting may be formed of a composite material. The fitting may have an H- shape and may have first and second longitudinally extending sections that extend beyond opposite sides of the strap. Each longitudinally extending section is configured to overlie at least two stringers (14) of a respective fuselage section. The fitting may also have a medial portion (36) upon which the shear tie is seated.