Segmented Wind Turbine Blade Geometry for Lower Joint Loads
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Solution Overview
Problem
Existing wind turbine blade designs face challenges in adapting to longer blades while maintaining competitive costs and minimizing production resource investments, with modularization leading to increased loads due to excess weight, necessitating a method to optimize mass and AEP without impacting existing production lines.
Innovation Solution
A methodology is developed to reduce the chord and thickness of the outboard module, combined with extending the blade length at the tip, to minimize loads and production costs, while using existing molds for both standard and slender blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the blade is modularized with joints, then the blade can be assembled in sections for transport, but the joint weight increases the overall blade mass and induces excessive loads
Solution Approach 1:
The blade is divided into inboard and outboard modules that can be assembled separately and transported independently, then joined on-site. This segmentation enables modular assembly capability while allowing optimization of each module's mass independently
Solution Approach 2:
The joint design parameters are optimized by adjusting the thickness distribution and chord dimensions at the joint location. The parameter t(x) defines the thickness profile that transitions from the inboard module through the joint to the outboard module, minimizing joint mass while maintaining structural integrity and reducing excessive loads
2Force
If the chord and thickness are reduced to minimize joint loads, then the loads at the joint section decrease, but the AEP (annual energy production) is reduced
Solution Approach 1:
The blade geometry is optimized locally at different sections: the joint area has reduced chord and thickness to minimize loads, while the outboard module extends the blade length to recover AEP. This local quality variation allows simultaneous optimization of joint loads and energy production
Solution Approach 2:
Instead of uniformly increasing chord or thickness throughout the blade, the solution extends the blade length in the spanwise dimension. This dimensional change recovers AEP without increasing joint loads, as the additional length is achieved through outboard module extension rather than root section enlargement
3Power
If the blade length is extended at the tip to recover AEP, then the energy production increases, but the loads at the blade root increase
Solution Approach 1:
The blade is segmented into inboard and outboard modules, allowing the outboard module to be extended in length without proportionally increasing the mass of the inboard module or the joint. This segmentation enables AEP recovery through length extension while controlling root loads
Solution Approach 2:
The thickness parameter t(x) is optimized as a function of position along the blade, with specific profiles defined for the inboard module, joint, and outboard module. This parameter optimization ensures that the extended outboard module generates additional AEP while the thickness distribution minimizes blade root loads
4Shape
If new molds are designed for slender blade configurations, then the aerodynamic design is optimized, but the production cost and investment increase
Solution Approach 1:
The joint mold is designed with universal capability to produce both standard and slender blade configurations. By making the mold multi-functional, the system achieves optimized aerodynamic profiles for different blade types without requiring separate dedicated molds for each configuration
Solution Approach 2:
The mold design incorporates adjustable or reconfigurable elements that allow dynamic adaptation between producing standard and slender blade profiles. This dynamic capability enables a single mold to serve multiple aerodynamic design requirements
Data Source
AI summary
A method for obtaining an improved segmented blade, wherein, for a blade 95 m long with the joint disposed 25-30 m from the blade tip: a) the chord and overall thickness in the 20 m of the outboard module are reduced by 75%; b) the outboard module is extended by 1 m; c) joining elements per cap are reduced from 10 to 8, and the blade mass from 800 kg to 640 kg, reducing the impact for the joint mass on the rest of the wind turbine; and d) loads at the blade root are reduced by 11% without affecting wind turbine productivity. The standard blade and the slender blade are manufactured in the same mould by adding detachable pieces at the end of the mould, depending on the required