Aircraft Stringer-Frame Intersection Without Clips
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Solution Overview
Problem
Conventional stringer-frame intersections in aircraft bodies fail to adequately transfer loads, are difficult to assemble, and obscure parts susceptible to cracking, making crack detection challenging.
Innovation Solution
A stringer-frame intersection design that eliminates the use of clips, featuring a stringer with tapered tabs and a frame with angled feet and cut-outs, allowing direct fixation of the stringer tabs to the skin while keeping the frame tabs exposed for visual inspection, enhancing load transfer and crack detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If clips are used to couple stringers with frames, then load transfer between frames and stringers is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the clips from the stringer-frame intersection assembly, eliminating the intermediate coupling component. The stringer tabs are fixed directly onto the skin, and the frame feet are fixed directly onto the skin or stringer tabs without requiring clips, thereby simplifying the device while maintaining load transfer capability through direct fixation.
Solution Approach 2:
The patent merges the functions of the stringer, frame, and skin by creating direct fixation connections between them. The stringer tabs and frame feet are both fixed directly onto the skin, integrating the load transfer path through the skin itself rather than requiring separate clip components to couple the stringers and frames.
2Strength
If conventional stringer-frame intersections are designed, then structural integrity is maintained, but visual access to parts susceptible to cracking is obscured
Solution Approach 1:
The patent segments the frame into multiple feet (first foot, second foot, third foot) that are spaced apart and fixed onto different locations. This segmentation allows the frame feet to be positioned to provide visual access to the skin and stringer tabs, enabling inspection of areas susceptible to cracking while maintaining structural integrity through the distributed fixation points.
Solution Approach 2:
The patent utilizes the spatial dimension by positioning the frame feet at different locations and orientations relative to the skin and stringer tabs. The first foot is fixed onto the skin, the second foot is fixed onto the first tab, and the third foot is fixed onto the skin, creating a three-dimensional arrangement that provides visual access to critical areas while maintaining structural strength.
3Strength
If multiple clips are used to couple stringers and frames, then load transfer is enhanced, but manufacturing cost increases
Solution Approach 1:
The patent eliminates the clips from the assembly, removing the need for these additional components entirely. The load transfer function previously performed by the clips is now achieved through direct fixation of the stringer tabs and frame feet onto the skin, reducing part count and manufacturing cost while maintaining load transfer efficiency.
Solution Approach 2:
The skin serves as the primary load transfer medium, with the stringer tabs and frame feet fixed directly onto it. The skin itself performs the load transfer function that would otherwise require separate clip components, allowing the structure to be self-sufficient and eliminating the need for additional manufactured parts.
Data Source
AI summary
Disclosed herein is a body of a mobile vehicle. The body includes skin, a stringer, and a frame. The skin comprises a first tab and a second tab, opposite the first tab. The first tab is fixed directly onto the skin and the second tab is fixed directly onto the skin. The frame comprises a cut-out, a first foot, and a second foot. The second foot is spaced apart from the first foot by the cut-out. The first foot is fixed directly onto the first tab of the stringer, such that the first tab of the stringer is immediately interposed between the first foot of the frame and the skin. The second foot is fixed directly onto the skin, such that no portion of the frame is fixed directly onto the second tab of the stringer.