Composite Stiffener Groove Integration for Fuselage Assembly

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Solution Overview

Problem

The assembly of frames, angles, and stabilizers in aircraft fuselages made of composite materials is costly and time-consuming due to the need for precise adjustments and the absence of direct contact between the frame and skin, which complicates the manufacturing process.

Innovation Solution

A method involving the use of molding elements on a mandrel to create grooves in networks, allowing stiffener preforms to intersect at nodes, with resin injection to assemble the stiffeners, eliminating the need for frames, angles, and stabilizers, and facilitating a single-piece structure with improved resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If frames, angles, and stabilizers are assembled on panels made of skin and stiffeners, then the structure achieves adequate mechanical resistance, but the manufacturing process becomes costly and time-consuming due to the number of operations and adjustments required

Engineering Contradiction:
Improvemechanical resistanceVSAvoidmanufacturing efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent merges the functions of frames, angles, and stabilizers into a single integrated network of stiffeners arranged in oblique patterns. Instead of assembling separate structural components on completed panels, the stiffeners are positioned in grooves during panel formation, creating a monolithic structure that achieves equivalent mechanical resistance while eliminating multiple assembly operations and adjustments

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The grooves for the stiffeners are created in advance on the mandrel before the skin is formed. This preliminary arrangement of molding elements allows the stiffeners to be positioned correctly during the panel forming process itself, rather than requiring subsequent assembly operations. The grooves guide the stiffener preforms into their final positions, ensuring proper alignment and integration before the skin is cured

Inventive Principle:
Principle #10Preliminary action

2Shape

If frames are attached perpendicular to stiffeners with angles and stabilizers, then the structure achieves proper geometric arrangement, but the manufacturing complexity increases due to the need for precise positioning and adjustment of multiple components

Engineering Contradiction:
Improvegeometric arrangementVSAvoidmanufacturing process complexity
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The patent combines the positioning functions of frames, angles, and stabilizers into a single integrated stiffener network. The molding elements create grooves that inherently guide and position the stiffeners in the correct oblique arrangement, eliminating the need for separate positioning operations for multiple component types and reducing manufacturing process complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The grooves created by the molding elements act as intermediaries that facilitate the positioning of stiffeners. These grooves are formed in advance on the mandrel and serve as guides that automatically position the stiffener preforms in the correct locations and orientations, simplifying the overall positioning process without requiring complex adjustment mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If stiffeners are arranged in oblique networks instead of conventional frame structures, then the manufacturing process is simplified and time is reduced, but the structural design becomes more complex

Engineering Contradiction:
Improvemanufacturing speedVSAvoidstructural design complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges multiple conventional structural elements (frames, angles, stabilizers) into a single oblique stiffener network arrangement. This integration simplifies the manufacturing process by reducing the number of assembly operations while the oblique geometry provides efficient load distribution, achieving both manufacturing efficiency and structural performance

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the geometric parameters of the stiffener arrangement from conventional orthogonal frame structures to oblique networks with specific angles (e.g., 60 degrees). This parameter change enables the stiffeners to intersect and share loads more efficiently, providing equivalent or superior mechanical resistance while simplifying the manufacturing process through integrated positioning

Inventive Principle:
Principle #35Parameter changes

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 method reduces manufacturing time and costs by simplifying the assembly process, achieving equivalent resistance without the need for additional structural components, and allows for a geodesic arrangement of stiffeners for optimal mechanical force distribution.

Implementation Method 1

injection of resin so as to assemble the stiffeners

Methodology Applied
Scientific EffectResin infiltration and bonding: Adhesive

Data Source

PatentEP2567806B1Method and device for the fabrication of a structure comprising a skin and stiffeners
Publication Date: 2017.02.22 AIRBUS OPERATIONS (SAS)
  • EP2567806B1 patent drawingFigure 1a~1c
  • EP2567806B1 patent drawingFigure 2~5
  • EP2567806B1 patent drawingFigure 6~8

AI summary

The method involves positioning molding elements on a chuck to form grooves between the molding elements, where the grooves are formed at networks (6a-6c), and the groove of one of the networks meets the groove of other network at a node (8), and a surface defined by longitudinal extension of the groove of the network is not normal to an axis of the chuck. Preforms of stiffeners (4) are positioned in the grooves such that two stiffeners meet at the node. Resin is injected into the preforms of the stiffeners to assemble the stiffeners. Independent claims are also included for the following: (1) a device for manufacturing a structure, comprising a skin and stiffeners fixed on the skin (2) a fuselage of an aircraft.