Composite Cooling via Carbon Nanotube Joule Heating

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Solution Overview

Problem

The production of fiber composite components for aircraft often results in thermal stresses and deformations due to uneven cooling, particularly in areas with thinner and thicker material thicknesses, leading to manufacturing-related issues and potential deformations.

Innovation Solution

A method involving the use of carbon nanotubes for remote Joule heating, where carbon nanotubes are strategically placed to influence temperature locally within the composite material, counteracting thermal deformations by controlling the temperature through embedded heating elements and adjusting current flow during the cooling process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional cooling process is used for fiber composite components with varying material thickness, then manufacturing simplicity is maintained, but thermal stresses and deformations occur due to uneven cooling rates between thinner and thicker areas

Engineering Contradiction:
Improvedimensional accuracyVSAvoidcooling system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by implementing region-specific cooling measures: different cooling rates are applied to the first region (thinner area) and second region (thicker area) separately. The cooling device is divided into first and second cooling regions with independent control, allowing each area to cool at an optimal rate for its thickness, thereby preventing thermal stresses and deformations while maintaining manufacturing precision.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The cooling device is segmented into multiple independent cooling regions (first cooling region and second cooling region) that can be controlled separately. This segmentation allows different cooling parameters to be applied to different areas of the component based on their thickness requirements, resolving the contradiction between manufacturing precision and device complexity.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If additional heating measures are implemented to compensate for thermal deformations, then manufacturing precision is improved, but energy consumption and process complexity increase

Engineering Contradiction:
Improvesurface planarityVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by implementing the differential cooling strategy during the cooling process itself, rather than adding corrective heating measures after deformation occurs. By controlling the cooling rates of the first and second regions differently from the outset, the thermal stresses are prevented from developing in the first place, achieving surface planarity without additional energy-intensive heating corrections.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent converts the potentially harmful effect of thermal gradients into a beneficial outcome by deliberately creating controlled thermal differences between regions during cooling. The slower cooling of the thicker second region and faster cooling of the thinner first region, which could otherwise cause deformation, is used strategically to maintain dimensional accuracy and prevent stress concentration.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If uniform cooling rate is applied across the entire component, then process simplicity is maintained, but thermal stresses develop due to different thicknesses requiring different cooling rates

Engineering Contradiction:
Improvecooling process simplicityVSAvoiddimensional tolerance
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent implements local quality by dividing the cooling device into distinct cooling regions (first and second cooling regions) that apply different cooling rates to different areas of the component. The thinner first region receives faster cooling while the thicker second region receives slower cooling, optimizing dimensional tolerance without significantly complicating the manufacturing process.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies parameter changes by varying the cooling rate parameter across different regions of the component. The cooling device is configured to provide different thermal parameters (cooling rates) to the first and second regions based on their thickness characteristics, thereby achieving precise dimensional control while maintaining ease of manufacture through a systematically designed cooling process.

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 approach enables precise control over the cooling process, reducing deformations and allowing for the production of perfectly planar surfaces with tighter manufacturing tolerances, thus improving the assembly accuracy and reducing technical effort.

Implementation Method 1

carbon nanotubes for remote Joule heating, where carbon nanotubes are strategically placed to influence temperature locally within the composite material

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

controlling the temperature through embedded heating elements and adjusting current flow during the cooling process

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3575066B1Method for producing a component made of fibre composite material
Publication Date: 2021.11.10 AIRBUS OPERATIONS GMBH
  • EP3575066B1 patent drawingFigure 1~3
  • EP3575066B1 patent drawingFigure 4~5
  • EP3575066B1 patent drawingFigure 6~7

AI summary

To avoid or reduce manufacturing-related deformations (38) in composite material components (10) with thicker and thinner (26, 28) material regions, a local control of the temperature inside one of the regions (26, 28) during a cooling process is proposed. In a preferred embodiment, strips (80) of carbon nanotubes (52) are embedded in the component (10) so that local temperature control is achieved by internal heating of the material via the remote Joule heating effect.