Aircraft Wing Discrete Stiffeners Axial Load Management

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Solution Overview

Problem

Existing aircraft wing designs with integral stringers face challenges in reducing part count and complexity while achieving lightweight and cost-effective construction, particularly in managing axial loads and maintaining structural integrity.

Innovation Solution

The use of non-integral, discrete stiffeners made from composite materials like carbon fiber reinforced plastic (CFRP) that are not designed to receive substantial axial loads from the wing panels, instead directing these loads through a continuous side of body web to a rear spar, reducing the need for additional structural components and simplifying the wing's configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If integral stringers are used to receive and direct axial loads toward ribs, then structural integrity is maintained, but part count and complexity increase

Engineering Contradiction:
Improvestructural integrityVSAvoidpart count and complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent extracts the axial load-bearing function from the stiffeners by deliberately designing them not to receive substantial axial loads. Instead, axial loads are directed through the wing panels and side of body web to the rear spar, while stiffeners focus solely on providing compressional stability and preventing buckling. This separation of functions reduces the need for additional structural components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent utilizes composite materials, specifically carbon fiber reinforced plastic (CFRP), for the stiffeners. This material choice enables the stiffeners to provide high compressional stability and buckling prevention while maintaining lightweight construction, thus achieving structural integrity without requiring heavier or more numerous components.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If discrete stiffeners are used instead of integral stringers, then weight is reduced, but structural complexity in load management increases

Engineering Contradiction:
Improvewing weightVSAvoidload management complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The side of body web performs multiple functions: it provides a continuous load path for axial loads from the wing panels to the rear spar, and simultaneously supports the discrete stiffeners for compressional stability. This multi-functionality simplifies load management by consolidating load-bearing functions into fewer components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The side of body web acts as an intermediary element that mediates between the wing panels and the rear spar, providing a continuous load path for axial loads. This intermediary structure simplifies the overall load management system by creating a straightforward load transfer path without requiring complex arrangements of integral stringers.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If non-integral stiffeners not designed for axial loads are used, then manufacturing cost and complexity are reduced, but structural design complexity increases

Engineering Contradiction:
Improvemanufacturing cost and complexityVSAvoidstructural design complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent segments the structural functions into distinct components: wing panels carry axial loads, side of body web provides continuous load path, and discrete stiffeners provide compressional stability. This segmentation allows each component to be optimized for its specific function, simplifying manufacturing while the overall system achieves structural integrity through coordinated design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of designing stiffeners to carry axial loads (traditional approach), the patent inverts the approach by deliberately designing them not to receive substantial axial loads. This inversion simplifies stiffener manufacturing and design, while the axial load path is routed through the wing panels and side of body web to the rear spar.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3293107B1Aircraft wings and aircraft including such aircraft wings
Publication Date: 2020.08.26 THE BOEING CO
  • EP3293107B1 patent drawingFigure 1
  • EP3293107B1 patent drawingFigure 2
  • EP3293107B1 patent drawingFigure 3

AI summary

Aircraft wings and aircraft including such aircraft wings are disclosed. An example apparatus includes an aircraft wing having a first panel; a second panel; ribs coupled between the first and second panels; and stiffeners coupled between the ribs in a spanwise direction and to the first panel, the coupling between the stiffeners and the first panel to deter axial loads from being received by the stiffeners, the stiffeners to increase a compressional stability of the first panel, wherein the coupling between the stiffeners and the first panel are indirect couplings formed via clips, the couplings formed via the clips deter the axial loads from being received by the stiffeners while increasing the compressional stability of the first panel.