Aircraft Shell Frame Segmentation for Bulge-Free Assembly
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Solution Overview
Problem
The manufacturing of aircraft or spacecraft shell components is labor-intensive and weight-heavy due to the need for numerous rivets and clips, with geometric constraints limiting the repositioning of integral frames, leading to increased costs and risk of local bulging when trying to accommodate curved skin panels.
Innovation Solution
A method involving an elastic bending of the skin panel to allow for the insertion of stringers into mouseholes without requiring simultaneous insertion, enabling smaller hole sizes and longer frame segments, thus reducing weight and manufacturing complexity while allowing for automation and precise contouring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If integral frames with mouseholes are used to eliminate clips and reduce assembly labor, then assembly complexity is reduced, but geometric constraints severely limit repositioning of the frame during assembly
Solution Approach 1:
The frame is divided into multiple segments that can be independently positioned and assembled. This segmentation allows the frame to be repositioned during assembly by adjusting individual segments, overcoming the geometric constraints of integral frames with mouseholes while maintaining the simplified assembly structure.
Solution Approach 2:
The frame structure is made dynamic through adjustable segments that can be repositioned during assembly. This dynamic capability allows the frame to adapt to different positions on the curved skin panel, resolving the contradiction between simplified assembly structure and repositioning flexibility.
2Adaptability or versatility
If mouseholes are made large to enable repositioning of the frame, then repositioning capability is improved, but the risk of local bulging in the outer skin increases
Solution Approach 1:
By segmenting the frame, smaller mouseholes can be used in each segment while still achieving overall repositioning capability. This eliminates the need for large mouseholes that would cause skin bulging, as each small mousehole in a segment causes minimal local deformation.
Solution Approach 2:
Different segments of the frame can have differently sized and positioned mouseholes optimized for their specific locations on the curved skin. This local optimization allows repositioning capability without requiring uniformly large mouseholes that would cause bulging across the entire frame.
3Adaptability or versatility
If the frame is divided into short segments to enable repositioning, then repositioning capability is improved, but the weight of the aircraft increases due to additional segment connections
Solution Approach 1:
The frame segments are designed with dynamic repositioning capability through controlled deformation of the skin panel between segments. This allows the segments to be positioned without requiring heavy mechanical connection mechanisms, reducing the weight penalty compared to rigidly connected short segments.
Solution Approach 2:
The skin panel acts as a flexible element that allows relative movement between frame segments during assembly. This flexible connection method is lighter than rigid mechanical connections, reducing the overall weight increase from segmentation while maintaining repositioning capability.
4Strength
If conventional riveting and welding methods are used to connect clips and frames, then structural strength is ensured, but the manufacturing process becomes very labor-intensive and difficult to automate
Solution Approach 1:
The frame segments are designed to be directly integrated with the skin panel through the mousehole-stringer connection, eliminating the need for separate clips. This merging of functions reduces the number of components and assembly steps, making the process easier to automate while maintaining structural strength through the direct frame-skin connection.
Solution Approach 2:
The clips and their associated riveting operations are extracted from the assembly process entirely. The frame segments connect directly to the skin through the mouseholes and stringers, removing the labor-intensive clipping and riveting steps while preserving the necessary structural connection.
5Reliability
If a large number of clips and rivets are used to connect frames to skin panels, then connection reliability is ensured, but the weight of the aircraft increases due to overlapping components
Solution Approach 1:
The frame segments are merged directly with the skin panel structure through the mousehole-stringer connection, eliminating the need for separate clips and rivets. This integration maintains connection reliability through the direct structural connection while removing the weight of overlapping components.
Solution Approach 2:
The clips and rivets are extracted from the connection system. The frame segments connect directly to the skin through the mouseholes and stringers, removing the redundant overlapping components that add weight while maintaining reliable structural connection.
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
This approach simplifies the manufacturing process, reduces weight, and enhances the strength-to-weight ratio of the shell component, enabling more precise and cost-effective production of aircraft or spacecraft components with improved assembly precision and automation capabilities.
Implementation Method 1
the skin panel is elastically bent, the first stringer is inserted into the first mousehole, and the elastic bend is released to insert the second stringer into the second mousehole
Implementation Method 2
the elastic bend is released to insert the second stringer into the second mousehole
Data Source
AI summary
A method of manufacturing a shell component for an aircraft or spacecraft includes positioning a skin panel, which includes a skin of the aircraft or spacecraft and first and second stringers stiffening the skin, opposite a frame having first and second mouseholes for receiving the first and second stringers, elastically bending the skin panel, inserting the first stringer into the first mousehole, and releasing the elastic bend to insert the second stringer into the second mousehole.