Resistance Welding Heating Element for Thermoplastic Aircraft Components

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Solution Overview

Problem

Resistance welding of thermoplastic components in aircraft production faces challenges such as inefficient heating over long lengths, leading to uneven bonds and high power consumption, particularly in bonding large fuselage segments where strong and high-quality welds are required.

Innovation Solution

A multifunctional heating element with electrically conductive elements, such as carbon fibers, that heat up upon voltage application and remain between welded components to enhance bond strength, combined with a system for continuously displacing the heated region along the components during welding, reducing power consumption and time expenditure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If resistance welding is performed over great lengths to bond fuselage segments, then the bond strength and quality are improved, but current losses occur resulting in inefficient heating and high power consumption

Engineering Contradiction:
Improvebond strengthVSAvoidpower consumption
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The heating element is divided into multiple independent heating zones along its length, allowing selective activation of only the zones currently needed for welding. This segmentation enables localized heating rather than heating the entire length, significantly reducing power consumption while maintaining bond strength quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heating element incorporates a movable contact system that dynamically shifts the active heating zone along the element's length as welding progresses. This dynamic repositioning ensures that heating is always applied at the current welding location rather than continuously across the entire length, optimizing energy efficiency.

Inventive Principle:
Principle #15Dynamics

2Strength

If resistance welding is performed over great lengths, then the bond strength is improved, but uneven or flawed welded bonds result due to current losses

Engineering Contradiction:
Improvebond strengthVSAvoidwelding quality
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

Dividing the heating element into discrete zones ensures that each zone can be independently controlled and optimized. This prevents heat loss and temperature variations that would occur in continuous long-length heating, ensuring uniform heating quality across the entire weld length while maintaining high bond strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of applying heat across the entire welding length simultaneously, the system applies heat partially and sequentially to specific zones as needed. This partial action approach prevents overheating in some areas while ensuring adequate heating in others, eliminating the uneven heating that causes welding defects.

Inventive Principle:
Principle #16Partial or excessive action

3Ease of manufacture

If conventional heating elements are used for resistance welding, then the welding process can be performed, but the heating element does not contribute to the structural strength of the welded bond

Engineering Contradiction:
Improvewelding process simplicityVSAvoidwelded bond strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The heating element serves dual functions: it generates heat for the resistance welding process and simultaneously acts as a structural reinforcement element within the welded bond. This multi-functionality is achieved by using electrically conductive, load-bearing materials such as carbon fibers or metal strands that can both conduct electricity for heating and provide mechanical strength to the joint.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The heating element is constructed from composite or hybrid materials that combine electrical conductivity with high mechanical strength properties. Examples include carbon fiber bundles or metal matrix composites that can withstand both the thermal and mechanical demands of the welding process while contributing reinforcement to the final bonded structure.

Inventive Principle:
Principle #40Composite materials

4Ease of manufacture

If rivet connections are used to connect skin sections, then the components can be joined, but tension concentrations occur due to punctiform connections

Engineering Contradiction:
Improveconnection simplicityVSAvoidconnection strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention replaces the mechanical rivet connection system with a thermal bonding process using resistance welding. This substitution eliminates the need for discrete fasteners that create stress concentration points, instead creating a continuous bonded joint that distributes loads more evenly across the connection area, thereby improving connection strength.

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

5Strength

If adhesive bonding is used to connect components, then the bond can be formed, but complex surface preparation and high time expenditure for curing are required

Engineering Contradiction:
Improvebond strengthVSAvoidcuring time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The invention replaces the chemical adhesive bonding process with a thermal resistance welding process. This substitution eliminates the lengthy curing time associated with adhesives, as resistance welding achieves bond strength through localized melting and bonding of thermoplastic materials in a matter of seconds or minutes, while also eliminating the need for complex surface preparation.

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

Enables high-strength, high-quality welds over long lengths with reduced power consumption and time, improving the bonding process of large fuselage segments by maintaining continuous localized heating and reinforcing the bond with the conductive elements aligned in the main load direction.

Implementation Method 1

one or more electrically conductive elements, which heat up upon application of an electric voltage to the heating element, in order to weld a first component to a second component in a region electrically heated by the heating element

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

A first component 110 and a second component 120 are bonded to one another in this case. For this purpose, a heating element 130, which is electrically conductive, is arranged between the components 110, 120 along the welding section in order to generate heat in the bonding region.

Methodology Applied
Scientific EffectElectrical resistance heating: Joule Heating

Data Source

PatentEP3611010A1Heating element, device, and method for resistance welding of thermoplastic components, in particular for the production of aircraft, and aircraft
Publication Date: 2020.02.19 AIRBUS OPERATIONS GMBH
  • EP3611010A1 patent drawingFigure 1~2
  • EP3611010A1 patent drawingFigure 3a~3b
  • EP3611010A1 patent drawingFigure 4~6

AI summary

A heating element (30) for resistance welding of thermoplastic components for aircraft comprises electrically conductive elements (30a) in the form of wires or fibres, which heat up upon application of an electric voltage to the heating element (30), to weld a first component (11) to a second component (12) in a region electrically heated by the heating element (30). The electrically conductive elements (30a) extend parallel to one another between contact regions (35, 36) for electrically contacting the heating element (30). After the welding procedure, the heating element (30) remains between the welded components (11, 12) to enhance the strength of the welded bond. A device for bonding thermoplastic components by resistance welding comprises the heating element (30) and a unit (31, 32) in the form of roller electrodes for displacing an electrically heated region of the components (11, 12) in the welding direction. The electrically conductive elements (30a) extend parallel to the axis of rotation (31a, 32a) of the roller electrodes.