Aircraft Rear Fuselage Composite Shell Design
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Solution Overview
Problem
The existing manufacturing processes for aircraft fuselage rear sections are inefficient, with time-consuming tasks such as riveting frames to the skin and limited optimization of load-specific components, leading to high costs and inaccuracies in assembly.
Innovation Solution
The process is optimized by disaggregating the rear fuselage section into an upper and lower shell, each with distinct geometries and load requirements, using integrally formed omega-shaped and T-shaped stringers, and shear-ties, and employing different composite material layering techniques like Fiber Placement and ATL for assembly, eliminating the need for direct riveting of frames to the skin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If frames are directly fastened to the skin using riveting, then structural connection is achieved, but manufacturing time and complexity increase significantly
Solution Approach 1:
The skin and shear-ties are merged into a single integrally formed composite component manufactured as one piece using autoclave curing. This eliminates the need for separate riveting operations to attach shear-ties to the skin, reducing manufacturing steps while maintaining structural integrity
Solution Approach 2:
Shear-ties serve as an intermediary element that is integrally formed with the skin and provides attachment points for frames. This mediator structure allows frame attachment without direct riveting to the skin, simplifying the manufacturing process
2Strength
If different stringer types are used for upper and lower shells, then load-specific optimization is achieved, but manufacturing complexity increases
Solution Approach 1:
Different stringer geometries (omega-shaped for upper shell, T-shaped for lower shell) are applied to different regions based on their specific load requirements. The upper shell uses omega-stringers to handle higher loads from stabilizer attachments, while the lower shell uses simpler T-shaped stringers for lower load conditions
Solution Approach 2:
The fuselage shell is segmented into upper and lower sections, each with its own optimized stringer configuration. This allows independent optimization of each section's structural properties according to local loading conditions
3Shape
If the rear fuselage section is assembled from multiple panels, then geometric flexibility is improved, but assembly accuracy and tolerance control deteriorate
Solution Approach 1:
The skin panels with stringers and shear-ties are pre-assembled and cured together in the autoclave before final fuselage assembly. This preliminary action ensures precise geometric relationships and tolerance control are established during the controlled curing process, rather than relying on post-assembly adjustments
Data Source
AI summary
A lower fuselage shell for an aircraft rear fuselage section, wherein the lower fuselage shell is made of a composite material and comprises at least one lower skin and stringers integrally formed with the lower skin, and frame segments extending crosswise relative to the stringers. Shear-ties are co-cured or co-bonded with the lower skin and extend crosswise relative to the stringers. Frame segments are fastened to the shear-ties, such that the frame segments are distanced from the lower skin. An aircraft rear fuselage section comprises an upper fuselage shell and the described lower fuselage shell. The upper fuselage shell has an upper skin reinforced with omega-shaped stringers, and the lower shell has a lower skin reinforced with T-shaped stringers.