Integrated Composite Infused Box for Aircraft Torsion Structures

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Solution Overview

Problem

Current manufacturing processes for torsion boxes in aircraft structures are complex, labor-intensive, and costly, involving numerous components and assembly operations, with weight penalties and high production costs due to the use of mechanical bonds and separate curing processes, which hinder the integration of composite materials effectively.

Innovation Solution

A method utilizing Liquid Resin Infusion (LRI) technology to manufacture a highly integrated infused box with two semiboxes, each with reinforcing elements in specific directions, reducing the number of components and curing processes, eliminating the need for an autoclave, and simplifying the assembly by co-infusing major quantities of joints, thereby reducing the number of rivets and assembly stages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional multi-rib structure with spars and stiffened covers is used, then structural strength and stiffness are achieved, but weight increases and manufacturing complexity increases

Engineering Contradiction:
Improvestructural strengthVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent merges multiple structural components (skins, ribs, spars, stringers) into a monolithic integrated box structure manufactured by ATL, eliminating the need for separate components and mechanical joints. This integration maintains structural strength while reducing weight by removing redundant joining elements and simplifying the overall architecture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and eliminates the centre joining rib from the traditional multi-rib structure, replacing it with an integrated box design. This removal of unnecessary components reduces weight while the ATL manufacturing process ensures structural integrity is maintained through monolithic construction.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If traditional manual manufacturing process with separate curing is used, then manufacturing precision is achieved, but productivity decreases and production cost increases

Engineering Contradiction:
Improvemanufacturing precisionVSAvoidproductivity
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent combines multiple separate curing processes into a single ATL manufacturing step, where all components (skins, ribs, spars, stringers) are cured simultaneously as one integrated structure. This merging of processes dramatically increases productivity while the automated nature of ATL ensures consistent manufacturing precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces manual manufacturing operations with automated ATL manufacturing. The automated fiber placement and curing processes eliminate manual labor while maintaining or improving manufacturing precision through computer-controlled operations, simultaneously increasing productivity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If mechanical bonds (rivets) are used for assembly, then structural integrity is maintained, but weight increases and aerodynamic quality deteriorates

Engineering Contradiction:
Improvestructural integrityVSAvoidweight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent merges all structural components into a single monolithic structure manufactured by ATL, eliminating the need for mechanical bonds such as rivets. The continuous fiber reinforcement and resin matrix provide structural integrity without discrete joining elements, reducing weight and improving aerodynamic surface quality.

Inventive Principle:
Principle #5Merging (Combining)

4Manufacturing precision

If traditional assembly with complicated jigs and multiple joining elements is used, then assembly precision is achieved, but device complexity increases and production cost increases

Engineering Contradiction:
Improveassembly precisionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges all components into an integrated structure manufactured in a single ATL process, eliminating the need for complicated jigs and multiple assembly operations. The automated manufacturing process inherently ensures precision through computer-controlled fiber placement and curing, simplifying the overall manufacturing system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces complex mechanical assembly systems (jigs, fixtures, manual joining) with automated ATL manufacturing. The digital control systems in ATL provide precise positioning and placement without requiring physical jigs, reducing device complexity while maintaining or improving assembly precision.

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

This approach significantly reduces manufacturing and assembly operations, lowers weight by minimizing mechanical bonds, and enhances aerodynamic quality by reducing the complexity and cost of production while maintaining structural integrity.

Implementation Method 1

A method utilizing Liquid Resin Infusion (LRI) technology to manufacture a highly integrated infused box

Methodology Applied
Scientific EffectLiquid Resin Infusion: Permeation

Data Source

PatentEP2889214B1Highly integrated infused box made of composite material and method of manufacturing
Publication Date: 2020.02.05 AIRBUS OPERATIONS SL
  • EP2889214B1 patent drawingFigure 1~6
  • EP2889214B1 patent drawingFigure 7~9
  • EP2889214B1 patent drawingFigure 11~12

AI summary

Highly integrated infused box made of composite material with two skins (3), several ribs (4), several stringers (5), a front spar and a rear spar, comprising a first semibox (1) and a second semibox (2) joined by connecting means, in which the first semibox (1) comprises one skin (3) and the ribs (4), and the second semibox (2) comprises one skin (3), the front spar, the rear spar and the stringers (5). A manufacturing method is also provided, which comprises forming processes for the first semibox (1), the second semibox (2) and an assembly process of the first semibox (1) with the second semibox (2).