Web-Fastened Stringer Splice Fittings for Simpler Aircraft Assembly
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Solution Overview
Problem
The assembly of complex structures like aircraft fuselages using splice fittings requires a large number of fasteners, leading to increased weight and complexity, as well as the need for unsecured stringer ends to facilitate alignment, which complicates the assembly process and requires specialized training.
Innovation Solution
A splice fitting design where fasteners penetrate the web of the fitting to secure stringers, allowing them to be fully installed before splicing, with separate fasteners used to attach the fitting to the skin, eliminating the need for shared fasteners and simplifying the alignment process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If splice fittings use the same fasteners to secure both stringers and skin, then the number of fasteners is reduced, but the assembly process becomes more complex and requires specialized training
Solution Approach 1:
The fastening system is segmented into two distinct functions: web fasteners secure stringers to the splice fitting, while flange fasteners secure the splice fitting to the skin. This segmentation allows each fastener set to be installed independently, eliminating the need for unsecured stringer ends and simplifying the assembly process while maintaining reduced fastener quantity
Solution Approach 2:
Stringers are preliminarily secured to the splice fitting via web fasteners before the flange fasteners are installed. This preliminary action eliminates the need to leave stringer ends unsecured, allowing stringers to be fully installed and secured to the skin beforehand, thereby simplifying the overall assembly process
2Ease of operation
If splice fittings require flexibility at stringer ends for alignment, then alignment is facilitated, but the stringer ends must remain unsecured which complicates the assembly process
Solution Approach 1:
Alignment features are preliminarily built into the splice fitting design, allowing stringers to be aligned and secured simultaneously. This eliminates the need to leave stringer ends unsecured, as the alignment mechanism is integrated into the fitting itself rather than requiring flexible, unsecured stringer ends
3Reliability
If splice fittings use a large number of fasteners, then secure attachment is achieved, but weight increases
Solution Approach 1:
The fastening system is segmented into web fasteners and flange fasteners with distinct functions, allowing for optimized fastener selection and placement. This segmentation enables secure attachment with fewer total fasteners by eliminating redundant fastening points and allowing each fastener to serve its specific purpose efficiently
Data Source
AI summary
Systems and methods are provided for installing splice fittings. One embodiment is a method for forming a splice between stringers. The method includes aligning a web of a splice fitting with a web of a first stringer and a web of a second stringer, and coupling the first stringer and the second stringer by installing fasteners that secure the web of the first stringer to the web of the splice fitting, and by installing fasteners that secure the web of the second stringer to the web of the splice fitting.