Aircraft Side of Body Joint Stringer Taper
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Solution Overview
Problem
The existing design of the side of body joint in aircraft wing assemblies is inadequate in managing complex loading during flight, leading to potential delamination and geometric discontinuities that can compromise the structural integrity of the wing and wing box.
Innovation Solution
Incorporating spanwise tapered bases and web cutouts in stringers at the side of body joint, which redistribute loads more gradually and prevent delamination by transferring stresses more effectively into the skin, with the taper angle between 10 and 15 degrees for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional stringer terminations are used at the side of body joint, then the structure is simpler to manufacture, but load discontinuities and delamination occur under complex flight loading
Solution Approach 1:
The stringer base is given a spanwise tapered geometry with a knife-edge termination at the skin, creating a localized geometric variation at the critical joint region. This local quality change allows for gradual load redistribution without requiring complex modifications throughout the entire stringer structure.
Solution Approach 2:
The spanwise taper creates a curved transitional surface rather than an abrupt termination. This curvature allows stresses to flow more smoothly from the stringer into the skin, preventing delamination while maintaining manufacturing feasibility through controlled machining operations.
2Ease of manufacture
If abrupt stringer terminations are used, then manufacturing is easier, but geometric discontinuities compromise structural integrity
Solution Approach 1:
The stringer base geometry is modified by changing the spanwise dimension through tapering, transitioning from a full-width base to a knife-edge termination. This parameter change allows loads to be distributed more uniformly along the span, improving manufacturing precision requirements while remaining manufacturable.
3Reliability
If web cutouts are added to stringers, then load redistribution is improved, but manufacturing complexity increases
Solution Approach 1:
The stringer web is segmented by introducing cutouts that remove material in strategic locations. This segmentation allows loads to be redistributed around the cutout regions, preventing stress concentration and delamination at the stringer-skin interface while maintaining overall structural integrity.
Data Source
AI summary
An aircraft includes a wing and a wing box. The wing is joined to the wing box at a side of body joint. The wing and the wing box each includes lower skin and a plurality of stringers on the skin. Ends of at least some of the stringers at the side of body joint have a web cutout and a base that is spanwise tapered to a knife edge at the skin.