Friction Stir Welded Wing Fuselage Interface Structure

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Traditional structural elements in airplane central wing boxes face issues with mechanical strength, weight, fragility, and high manufacturing costs due to bolted or riveted junctions, and are prone to distortion during machining.

Innovation Solution

A structural element with a web and profiled elements connected via friction-stir-welded butt-type seams, eliminating overlaps and using lithium-containing aluminum alloys for improved strength and weight savings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If bolted or riveted junctions are used to assemble the structural element, then the manufacturing complexity is reduced and assembly is simplified, but the mechanical strength decreases and the structure becomes more fragile due to holes and overlap zones

Engineering Contradiction:

Improveassembly simplicityVSAvoidmechanical strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent merges multiple separate elements (web and profiled elements) into a unified structure through friction-stir-welded butt-type seams, eliminating the need for bolted or riveted junctions. This merging approach maintains manufacturing simplicity while significantly improving mechanical strength by removing holes and overlap zones that create fragility points.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical fastening system (bolts or rivets) with a friction-stir-welding process. This substitution eliminates the need for holes and overlap zones, thereby removing the sources of fragility while maintaining ease of manufacture through a streamlined assembly process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If a single machined metal block is used to manufacture the structural element, then the mechanical strength is improved and junction-related disadvantages are eliminated, but the manufacturing cost increases significantly due to material quantity and numerous machining operations

Engineering Contradiction:

Improvemechanical strengthVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent segments the structural element into separate components (web and profiled elements) that are manufactured independently and then joined through friction-stir-welding. This segmentation allows each component to be optimized for its specific function and manufactured more efficiently, reducing overall material usage and machining operations compared to a single monolithic block.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the manufacturing parameters from traditional bolting or riveting to friction-stir-welding with butt-type seams. This parameter change enables the use of separate components without compromising mechanical strength, thereby reducing material quantity and manufacturing cost while maintaining the strength benefits of a unified structure.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a single machined metal block is used, then junction-related fragility is eliminated, but distortion problems occur due to deformations during machining

Engineering Contradiction:

Improvestructural integrityVSAvoiddistortion control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

By segmenting the structural element into separate components that are joined through friction-stir-welding, the patent eliminates the need for extensive machining operations on a single large block. This reduces the cumulative deformations and distortions that would otherwise occur during multiple machining steps, while still achieving a unified structure with high structural integrity.

Inventive Principle:

Principle #1Segmentation

4Ease of manufacture

If overlap zones are present in the structural element, then assembly is facilitated, but the weight increases and the structure becomes more fragile

Engineering Contradiction:

Improveassembly facilitationVSAvoidstructural weight

Core Design Contradiction:

Ease of manufactureVSWeight of moving object

Solution Approach 1:

The patent replaces the overlap zone assembly method with friction-stir-welded butt-type seams. This substitution eliminates the need for overlapping elements, thereby removing the associated weight penalty and fragility issues, while maintaining assembly facilitation through a streamlined joining process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enhances mechanical strength, reduces distortions, eliminates shear forces, and achieves significant weight savings of around 5% while simplifying manufacturing and reducing costs.

Implementation Method 1

connected thereto by a friction-stir-welded butt-type seam

Methodology Applied

Scientific EffectFriction stir welding: Friction Welding

Data Source

PatentUS8720823B2Aircraft structural element located at the interface between a wing and the fuselage

Publication Date: 2014.05.13 AIRBUS OPERATIONS (SAS)

AI summary

An aircraft structural element situated at an interface between a wing and the fuselage, and including a web and profiled elements flanking the web. At least one the profiled element includes a flat part positioned without overlap in the continuation of a flat part of the web and connected thereto by a welded butt joint using friction stir welding.