Nested Aircraft Wing Box Joint Design
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Solution Overview
Problem
Current methods for connecting wing sections in aircraft structures are either heavy due to tensioning arrangements or complex and costly due to the use of multiple parts and complex joining procedures, such as cruciform and triform structures, which increase weight and manufacturing time.
Innovation Solution
An aircraft structure design featuring a joint where one sub-structure's end region overlaps inside the other, allowing for quick and lightweight assembly with shear-loaded bolts, reducing the need for complex shimming and minimizing the number of parts, using an overlap region where the first sub-structure's box cross-section is contained within the second sub-structure's box cross-section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a full tension fitting arrangement is used to connect two wing box sections, then the connection is quick and simple, but the weight penalty is significant due to the heavy tensioning arrangement
Solution Approach 1:
The first sub-structure is nested inside the second sub-structure in an overlap region, with the end regions overlapping such that one structure is contained within the other. This nesting arrangement eliminates the need for separate tension fitting components, achieving both simple assembly and weight reduction.
2Adaptability or versatility
If a cruciform and triform structure is used to connect two wing boxes, then the joining allows separate completion of wing boxes, but the joining procedure becomes complex requiring significant fettling and shimming
Solution Approach 1:
The overlapping nested configuration allows each wing box to be assembled separately and then joined by simply overlapping the end regions. The nested geometry inherently provides alignment and tolerance accommodation, eliminating the need for complex shimming and fettling procedures while maintaining separate assembly capability.
Solution Approach 2:
The joint is divided into distinct overlap regions where end regions of sub-structures overlap. This segmentation allows each sub-structure to be independently manufactured and assembled, then joined through a simplified overlapping process rather than requiring complex multi-component fittings.
3Strength
If a cruciform and triform structure with multiple parts is used, then the wing boxes can be connected, but the number of parts increases adding to costs and weight
Solution Approach 1:
The end regions of the sub-structures are merged through overlapping, combining the structural functions into a single integrated joint region. This eliminates the need for multiple separate parts (cruciform structures, triform structures, crown fittings, splice plates) and achieves connection integrity through the merged overlapping geometry.
Solution Approach 2:
By nesting one sub-structure inside the other through overlapping end regions, the design reduces the quantity of parts needed. The nested configuration provides structural integrity through the overlapping regions themselves, eliminating the need for numerous additional connecting components.
4Reliability
If traditional joining procedures with multiple parts are used, then connections can be made, but manufacturing time increases significantly
Solution Approach 1:
The nested overlapping design enables rapid assembly by eliminating complex multi-step joining procedures. The end regions are simply overlapped and secured, dramatically reducing assembly time while maintaining connection reliability through the robust overlapping geometry and shear-loaded fasteners.
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 design enables rapid and lightweight assembly of wing sections with reduced complexity and cost, utilizing shear-loaded fasteners to simplify the joining process and minimize weight, while maintaining structural integrity.
Implementation Method 1
bolts used to connect the two sub-structures are loaded under shear force
Data Source
AI summary
The present invention provides an aircraft structure comprising a first sub-structure, having a first box cross-section, a second sub-structure, having a second box cross-section, and a joint joining a first end region of the first sub-structure to second end region of the second sub-structure, wherein the joint comprises an overlap region where the end regions of the first and the second sub-structures overlap such that the first sub-structure is inside the second sub-structure. The present invention also provides an aircraft comprising such an aircraft structure and a method of manufacturing an aircraft structure.