Method for the resistance welding of fibre-composite components to give a fibre-composite structure, fibre-composite structure and fibre-composite component
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Solution Overview
Problem
Resistance welding of fibre-composite components, particularly thermoplastic-based aircraft structures, faces challenges with metal grids increasing weight and causing discontinuities, and carbon fibre-based solutions risking leakage currents and heat loss.
Innovation Solution
Incorporating carbon fibres with solid polymer-electrolyte coatings as conductive fibres within the jointing region, allowing for electrical insulation and high-temperature resistance, enabling efficient heating and bonding without weight increase or leakage issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal grid is placed in the jointing region for resistance welding, then electrical conduction is improved, but weight increases and structural discontinuity is created
Solution Approach 1:
The patent changes the material parameter from metal to carbon fibre, maintaining electrical conductivity while reducing weight. The carbon fibres have appropriate electrical resistance for heat generation and match the electrochemical environment of the fibre-composite material, solving both conduction reliability and weight issues simultaneously.
Solution Approach 2:
The patent uses carbon fibres that are compatible with the fibre-composite matrix material, creating a homogeneous composite structure rather than introducing a disparate metal grid. This maintains structural continuity and avoids the weight penalty of metal while ensuring proper electrical conduction for resistance welding.
2Weight of moving object
If carbon fibres are introduced as current-conducting components, then weight is reduced and structural continuity is maintained, but leakage currents and heat loss occur
Solution Approach 1:
The patent carefully selects and optimizes the electrical resistance parameter of the carbon fibres. By controlling the fibre diameter, length, and arrangement density, the resistance is tuned to generate sufficient heat for welding while minimizing energy loss as stray heat. This parameter optimization resolves the contradiction between using lightweight carbon fibres and preventing energy loss.
3Manufacturing precision
If uniformity of temperature distribution is maximized in the jointing zone, then welding precision is improved, but resistance uniformity becomes difficult to achieve
Solution Approach 1:
The patent achieves homogeneous distribution of carbon fibres in the jointing zone, ensuring uniform electrical resistance and temperature distribution across the welding area. This homogeneity is accomplished through proper fibre arrangement and density control, simplifying the welding process while maintaining high precision without requiring complex control systems.
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 minimizes leakage currents and heat loss, allows for high-temperature resistance welding of thermoplastics like PEEK, and integrates conductive fibres as reinforcement without structural discontinuities, enhancing the quality and efficiency of fibre-composite bonding.
Implementation Method 1
each conductive fibre comprises a carbon fibre with an electrically insulating coating
Implementation Method 2
A coating of this type can withstand temperatures above 700°C
Implementation Method 3
passing an electric current through a jointing zone that is to be welded; electrical resistance then causes heating of the said zone
Implementation Method 4
electrical resistance then causes heating of the said zone
Implementation Method 5
heats the jointing region to a welding temperature and melts the fibre-composite components in the jointing region
Data Source
Figure 1~3
Figure 4~5
AI summary
A method for the resistance welding of two fibre-composite components (1) to give a fibre-composite structure comprises arranging conductive fibres (2) within a jointing region (5) of the two fibre-composite components (1), where each conductive fibre (2) comprises a carbon fibre with an electrically insulating coating; passing an electric current through the conductive fibres (2) in a manner that heats the jointing region (5) to a welding temperature and melts the fibre-composite components (1) in the jointing region (5); and hardening the jointing region (5) in a manner that bonds the two fibre-composite components (1) by way of the jointing region (5) to give the fibre-composite structure.