Wind Turbine Blade Root Assembly With Non-Gas-Tight Infusion
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Solution Overview
Problem
Manufacturing rotor blade roots faces challenges due to limited vacuum access during infusion, leading to under-infused areas and potential defects, particularly at the connection between the blade root and the hub, which can cause increased stresses and fatigue.
Innovation Solution
Incorporating a non-gas tight feature, such as a fluid hole in the root plate or a non-gas tight connection between the root plate and the blade mold, to enhance resin flow and vacuum pressure, ensuring complete infusion and reducing manufacturing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a standard root plate is used during vacuum infusion, then the structure is simple and easy to manufacture, but the resin flow is limited and under-infused areas occur
Solution Approach 1:
The root plate is segmented into multiple functional zones: a first region with a non-gas tight feature (fluid hole) to enhance vacuum pressure and resin flow, and a second region without this feature to maintain structural integrity. This segmentation allows different parts of the root plate to serve different purposes during infusion.
Solution Approach 2:
The non-gas tight feature (fluid hole) acts as an intermediary element that mediates between the vacuum source and the composite material. It provides an additional pathway for vacuum pressure to act on the resin, improving resin flow and infusion completeness without requiring direct modification of the mold or vacuum system.
2Manufacturing precision
If vacuum infusion is applied only from one side, then the process is simple, but resin flow is limited and under-infused areas occur
Solution Approach 1:
The fluid hole in the root plate creates a new dimension for vacuum pressure application. Instead of relying solely on vacuum from the mold side, the fluid hole provides an additional vacuum pathway that draws resin from multiple directions, effectively adding a dimensional aspect to the resin flow pattern.
Solution Approach 2:
The invention utilizes pneumatic principles by introducing a fluid hole that allows vacuum pressure to act through a fluid pathway. The non-gas tight feature creates a pressure differential that drives resin flow through the composite material, leveraging pneumatic pressure distribution to improve infusion.
3Ease of manufacture
If root bolts are cured directly between skin layers, then machining is eliminated, but locating and maintaining root bolt position is challenging
Solution Approach 1:
The root plate with its structured features (through holes, non-gas tight feature) is prepared in advance to provide precise locating surfaces and positioning features for the root bolts. This preliminary preparation of the root plate ensures accurate root bolt positioning before the infusion process begins, eliminating the need for post-curing machining while maintaining precision.
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 improves resin distribution, minimizing defects and enhancing the structural integrity of the rotor blade root assembly by ensuring thorough infusion and effective attachment to the hub.
Implementation Method 1
The lack of vacuum pressure differential to drive the flow of resin to all areas of the part can lead to under infused areas of the composite
Implementation Method 2
curving a plurality of root bolts into the blade root during a vacuum infusion process
Implementation Method 3
Incorporating a non-gas tight feature, such as a fluid hole in the root plate or a non-gas tight connection between the root plate and the blade mold, to enhance resin flow and vacuum pressure
Data Source
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AI summary
A method for manufacturing a rotor blade root assembly includes placing outer skin layer(s) onto a blade mold and arranging a root plate with a plurality of through holes adjacent to an end face of the blade mold. The method also includes placing a plurality of root inserts atop the outer skin layer(s) and abutting against the root plate, with each of the root inserts defining a fastener hole. The method also includes inserting a root fastener into each of the aligned through holes and longitudinal fastener holes. Moreover, the method includes placing inner skin layer(s) atop the root inserts. Further, the root plate may include at least one fluid hole configured therethrough to provide a non-gas tight root plate. Alternatively, at least one seal may be arranged between the root plate and the blade mold that forms a non-gas tight connection with either or both of the root plate or the blade mold during a vacuum infusion process. Thus, the method includes securing the outer skin layer(s), the root inserts, the inner skin layer(s), and the root fasteners together to form the root assembly via the vacuum infusion process.