Composite Aircraft Torsion Box Monolithic Integration

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Solution Overview

Problem

The current manufacturing methods for aircraft torsion boxes using composite materials, such as CFRP, are costly and inefficient due to the high complexity and number of components, leading to increased weight and production costs.

Innovation Solution

A multi-spar and multi-rib torsion box configuration with integrated manufacturing, where the structural elements are formed into a monolithic ensemble using prepreg technology and autoclave curing, reducing the number of components and fasteners, and incorporating transverse ribs to enhance torsional rigidity and load distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional separate manufacture and assembly of structural elements is used, then manufacturing flexibility and quality control are improved, but manufacturing cost, time, and assembly complexity increase significantly

Engineering Contradiction:
Improvequality controlVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent merges multiple separate structural elements (skins, spars, ribs, stringers) into a single integrated monolithic torsion box manufactured through prepreg technology. This consolidation eliminates the need for separate manufacturing and assembly operations, directly reducing manufacturing time and complexity while maintaining quality control through integrated design and manufacturing processes.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If multiple separate structural elements are assembled together, then design flexibility and repairability are improved, but weight and assembly complexity increase

Engineering Contradiction:
Improvedesign flexibilityVSAvoidtorsion box weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

By combining multiple structural elements into a single monolithic torsion box, the patent eliminates the weight of fasteners, joints, and assembly fixtures required for separate components. The integrated structure removes unnecessary interfaces and connection details, reducing overall weight while maintaining design flexibility through the prepreg manufacturing process.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If traditional assembly process is used, then component inspection and quality verification are improved, but assembly time and labor requirements increase

Engineering Contradiction:
Improvequality verificationVSAvoidassembly time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent eliminates the entire assembly process by manufacturing the torsion box as a single monolithic component through prepreg technology. This consolidation removes all assembly time, labor requirements, and associated quality verification steps for joining components, while maintaining quality control through integrated manufacturing processes and final inspection of the complete structure.

Inventive Principle:
Principle #5Merging (Combining)

4Productivity

If integrated monolithic manufacturing is used, then manufacturing cost and time are reduced, but manufacturing complexity and tooling requirements increase

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidmanufacturing process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent utilizes composite materials (prepreg technology) to enable integrated monolithic manufacturing of the torsion box. The composite material process allows complex geometries to be formed in a single curing operation, eliminating the need for separate assembly operations. While tooling complexity increases, the elimination of multiple manufacturing and assembly steps results in overall cost and time reduction.

Inventive Principle:
Principle #40Composite materials

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 results in weight and cost reductions while improving the torsional rigidity of the torsion box, reducing deformations, and simplifying the manufacturing process by integrating structural elements, thereby enhancing overall efficiency.

Implementation Method 1

subjecting the curing assembly to an autoclave cycle to co-cure said laminated preforms

Methodology Applied
Scientific EffectCuring:

Data Source

PatentEP2735502B1An optimized torsion box for an aircraft
Publication Date: 2016.08.24 AIRBUS OPERATIONS SL
  • EP2735502B1 patent drawingFigure 1a~2a
  • EP2735502B1 patent drawingFigure 2b~4b
  • EP2735502B1 patent drawingFigure 5a~6c

AI summary

The invention provides an aircraft lifting surface with a torsion box (13) of a composite material comprising an upper skin (21), a lower skin (23), a front spar (18), a rear spar (20), one or more intermediate spars (19, 19') and a plurality of transverse ribs (25, 25', ...) arranged between the rear spar (20) and its adjacent intermediate spar (19') and/or between the front spar (18) and the adjacent intermediate spar (19) for improving its structural behavior. The invention also provides a manufacturing method of said torsion box.