Wind Turbine Blade Thermal Welding With External Resistive Heating
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Solution Overview
Problem
Existing methods for connecting pre-manufactured components of wind turbine blades, such as adhesive processes and infusion of resin, are time-consuming and add significant weight, while thermal welding methods face challenges in accessing resistive elements within the blade's interior cavity for efficient heating.
Innovation Solution
The use of a resistive element sandwiched between blade components, connected by an electrically conductive element extending through the blade shell, allows for external power supply, enabling efficient thermal welding without the need for adhesive and reducing weight by eliminating the need for adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive processes are used to connect blade components, then the connection is reliable, but the blade weight increases significantly and the manufacturing time increases
Solution Approach 1:
The patent replaces adhesive bonding (chemical/mechanical system) with thermal welding (thermal system). A resistive element is embedded in the overlap region between blade components, and electrical current is passed through it to generate heat via Joule heating, melting the thermoplastic resin to create a weld joint. This eliminates the need for adhesive while maintaining connection reliability.
Solution Approach 2:
The thermal welding process utilizes phase transition of the thermoplastic resin in the overlap region. The resistive element heats the resin above its melting point, causing it to transition from solid to molten state, then cools and solidifies to form a strong weld joint. This phase change enables reliable connection without adhesive.
2Reliability
If adhesive processes are used to connect blade components, then the connection is reliable, but the manufacturing time increases due to curing requirements
Solution Approach 1:
The patent replaces adhesive bonding (chemical system requiring curing) with thermal welding (thermal system). The resistive element generates heat through Joule heating, rapidly melting and bonding the thermoplastic resin. This thermal process eliminates the lengthy curing time required for adhesive to set and achieve full strength, significantly accelerating production.
Solution Approach 2:
The thermal welding process utilizes rapid phase transition of the thermoplastic resin from solid to molten and back to solid through controlled heating and cooling. This phase change occurs much faster than adhesive curing, enabling rapid connection of blade components while maintaining joint reliability.
3Weight of moving object
If thermal welding is used with resistive element inside the blade cavity, then adhesive can be avoided and weight reduced, but accessing and powering the resistive element becomes difficult
Solution Approach 1:
The patent embeds the resistive element within the overlap region of the blade components during the manufacturing process, nesting it inside the structure where it is most effective. The element is positioned between the overlapping parts, and its leads are routed through the structure to external connection points, allowing it to remain nested while still being accessible for power supply.
Solution Approach 2:
The patent uses electrical leads or conductive elements as intermediaries to bridge the resistive element (located inside the blade cavity) and the external power source. These intermediary conductors transmit electrical current through the blade structure to heat the resistive element, solving the accessibility problem while maintaining the weight benefits of internal placement.
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 facilitates faster connection of blade components, reduces weight, and simplifies the power supply to resistive elements, even in hard-to-reach interior locations, thereby enhancing manufacturing efficiency and reducing material weight.
Implementation Method 1
a resistive element arranged between the first and second blade components in the overlap region as a remnant of the thermal welding
Data Source
AI summary
A wind turbine blade is provided including a first and a second blade component connected with each other in an overlap region by thermal welding, the first blade component including a blade shell, a resistive element arranged between the first and second blade components in the overlap region as a remnant of the thermal welding, and an electrically conductive element extending through the blade shell and being electrically connected to the resistive element for supplying power to the resistive element during the thermal welding. The first and second blade components can be joined by thermal welding. Further, the resistive element used as heating element for thermal welding can be heated by electrical current even when the resistive element is difficult to assess from the interior cavity of the blade.