VARTM Mold Pressure Device for Rotor Blade Lightning Protection
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Solution Overview
Problem
Modern wind turbine rotor blades face structural damage and potential catastrophic failure due to flash-overs and mutual induction between lightning conductors and carbon fiber spar caps during lightning strikes, as existing manufacturing methods struggle to ensure reliable electrical conductivity and minimize manufacturing errors in large, complex structures.
Innovation Solution
A vacuum-assisted resin transfer molding (VARTM) method is employed to produce components with improved electrical connections by using electrically conductive beam fiber materials and mats, applying external pressure to minimize resin thickness and enhance conductivity, and integrating a pressure applying device with a flexible film to ensure consistent pressure distribution during the molding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vacuum assisted resin transfer molding is used to produce spar cap components, then manufacturing complexity is reduced, but electrical connection quality between conductive materials deteriorates due to resin accumulation at connection interfaces
Solution Approach 1:
The patent applies external pressure to the mold arrangement before resin injection to pre-compress the electrical connection interface between conductive beam fiber material and electrical conductor. This preliminary compression minimizes the gap and resin thickness at the connection interface, ensuring low electrical resistance before the resin infusion process begins, thus preventing electrical connection quality deterioration while maintaining manufacturing simplicity
Solution Approach 2:
The patent dynamically controls pressure parameters during the manufacturing process by applying external pressure (distinct from vacuum pressure) specifically at the electrical connection zones. This parameter change ensures minimal resin thickness and optimal contact pressure at connection interfaces, maintaining electrical reliability while using the simple VARTM process for manufacturing
2Reliability
If external pressure is applied to minimize resin thickness at electrical connections, then electrical conductivity improves, but device complexity increases due to additional pressure applying mechanisms
Solution Approach 1:
The patent integrates the pressure applying device with the existing mold arrangement structure, allowing the same system to perform both molding and electrical connection compression functions. The pressure applying device is positioned to act on multiple electrical connection points simultaneously, making it a multi-functional component that improves electrical conductivity without proportionally increasing overall device complexity
Solution Approach 2:
The patent uses the mold arrangement itself as an intermediary medium to transmit and distribute external pressure to the electrical connections. Rather than requiring complex direct pressure application mechanisms at each connection point, the mold structure serves as a pressure distribution intermediary, simplifying the overall device architecture while achieving the desired electrical connection quality
3Strength
If carbon fiber reinforced plastic is used for spar caps, then structural strength and electrical conductivity are improved, but susceptibility to lightning strike damage increases due to flash-overs between conductive elements
Solution Approach 1:
The patent applies different material properties to different zones: carbon fiber reinforced plastic is used in the spar cap structure where strength is needed, while electrically insulating materials are specifically placed at electrical connection interfaces and lightning conductor attachment points. This local differentiation maintains structural strength and electrical conductivity where needed while preventing flash-overs and lightning damage at critical interfaces
Solution Approach 2:
The patent introduces electrically insulating materials as intermediary layers between the conductive carbon fiber spar cap and the lightning conductor. This intermediary insulation prevents direct electrical contact that would cause flash-overs, while still allowing mechanical attachment and current dissipation functions to be performed, thus protecting against lightning strike damage while maintaining structural integrity
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
The method effectively improves the electrical quality of connections between conductive materials, reducing the risk of structural damage from lightning strikes and minimizing manufacturing errors, thereby enhancing the reliability and efficiency of rotor blade components.
Implementation Method 1
subjecting the mold arrangement to underpressure
Implementation Method 2
applying an external pressure on the electrical connection from outside the mold arrangement
Implementation Method 3
applying heat to the mold arrangement for curing the resin
Data Source
AI summary
Provided is a vacuum assisted resin transfer molding method for producing a component, in particular a spar cap, of a rotor blade including a lightning protection system, wherein the vacuum assisted resin transfer molding method includes the steps of: a) placing) an electrically conductive beam fiber material of an electrically conductive beam, an electrically conductive fiber mat and an electrical conductor of the component in a mold arrangement electrically connecting the electrically conductive beam fiber material to the electrical conductor by means of the electrically conductive fiber mat, wherein an electrical connection between the electrical conductor and the electrically conductive fiber mat is generated, c) subjecting the mold arrangement to underpressure, d) applying an external pressure on the electrical connection from outside the mold arrangement, e) injecting resin into the underpressurized mold arrangement, and f) applying heat to the mold arrangement for curing the resin.