Composite Spar Outward Flanges Assembly
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Solution Overview
Problem
Conventional composite spars for aircraft wings face challenges in assembly efficiency and structural integrity due to inward-facing flanges, which require interior access for attachment, leading to increased manufacturing time and cost, and are susceptible to electromagnetic interference and crack propagation.
Innovation Solution
The use of double-flanged and single-flanged spar caps with outward-facing flanges and tear straps, integrated through a co-curing process, allows for external attachment of skins and reduces the need for fasteners, enhancing structural stability and reducing assembly time and costs while minimizing electromagnetic susceptibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inward-facing flanges are used for spar cap attachment, then structural connection is achieved, but assembly time increases and manufacturing cost increases due to required interior access
Solution Approach 1:
The patent inverts the conventional inward-facing flange configuration by using outward-facing flanges on the spar caps. This allows the second skin to be attached from the exterior of the aircraft wing, eliminating the need for interior access and significantly reducing assembly time and complexity. The outward-facing flanges enable fasteners to be installed from outside the wing structure, transforming a complex interior assembly operation into a simpler exterior operation.
2Productivity
If multiple fasteners are used for skin attachment, then structural connection is achieved, but manufacturing cost increases and assembly time increases
Solution Approach 1:
The patent merges the attachment operations for the first and second skins into a single coordinated process. The outward-facing flanges on the spar caps allow both skin attachments to be performed simultaneously or in close sequence from the exterior, reducing the total number of discrete fastening operations and reducing manufacturing cost and time.
3Reliability
If conventional spar configuration is used, then structural support is provided, but electromagnetic interference susceptibility increases and crack propagation risk increases
Solution Approach 1:
The patent extracts the problematic inward-facing flange configuration that creates electromagnetic interference pathways and crack propagation risks. By removing this conventional feature and replacing it with outward-facing flanges, the design eliminates the interior attachment points that serve as electromagnetic interference sources and crack initiation sites, thereby improving structural integrity and electromagnetic compatibility.
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 configuration improves assembly speed, reduces manufacturing costs, enhances structural integrity by compressing plies, and strengthens the spar web, making the aircraft wing less susceptible to electromagnetic interference and crack propagation.
Implementation Method 1
integrated through a co-curing process
Implementation Method 2
enhances structural integrity by compressing plies
Data Source
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AI summary
An example aircraft wing includes a first skin, a second skin opposite to the first skin, and a composite spar. The composite spar includes a double-flanged spar cap, a single-flanged spar cap, a spar web connecting the double-flanged spar cap and the single-flanged spar cap, and a tear strap. The double-flanged spar cap includes an inward-facing flange and a first outward-facing flange, and the inward-facing flange and the first outward-facing flange are integrated with the first skin during a co-curing process. The single-flanged spar cap includes a second outward-facing flange that is attached to the second skin. The tear strap is stitched to an inner side of the spar web along at least a portion of a length of the composite spar.