Wind Turbine Blade Reinforcement for Load Transfer Without Weight Penalty
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Solution Overview
Problem
As wind turbine blades increase in size to enhance energy production, they face escalating loads that require reinforcement, leading to increased weight and further load challenges, creating a vicious cycle.
Innovation Solution
A pitch-controlled wind turbine design incorporates a reinforcing member made of fibre-reinforced composite material, extending from a connection point on the blade to a spar cap, with a core material to manage thickness and reduce weight, and a bearing structure for flexible connection points to distribute loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wind turbine blades are increased in size to enhance energy production, then energy production is improved, but loads on the blades increase
Solution Approach 1:
The blade structure is segmented into multiple functional components: spar cap for primary structural support, reinforcing members for localized strength enhancement, and core material for weight reduction. This segmentation allows each component to be optimized independently for its specific function, enabling larger blade sizes without proportionally increasing overall loads.
Solution Approach 2:
The patent employs composite materials throughout the blade structure, including fibre-reinforced materials for the spar cap and reinforcing members, and lightweight core materials. These composite materials provide high strength-to-weight ratios, allowing the blade to withstand increased loads from larger size while minimizing the weight penalty that would otherwise increase gravitational loads.
2Strength
If blades are reinforced to handle increased loads, then load-bearing capacity is improved, but weight of the blades increases
Solution Approach 1:
Reinforcement is applied locally rather than uniformly throughout the blade. Spar caps are positioned at the root and mid-section where bending moments are highest, while reinforcing members are strategically placed at connection regions. This local quality approach concentrates material where structurally necessary, maximizing load-bearing capacity while minimizing overall weight increase.
Solution Approach 2:
The patent introduces a third dimension to the blade structure by adding depth through spar caps and reinforcing members that extend into the blade thickness. This dimensional approach creates a three-dimensional load-bearing framework that efficiently distributes stresses throughout the blade volume, providing enhanced strength without requiring proportional increases in surface area or overall mass.
3Productivity
If blades are increased in size, then energy production is improved, but weight of the blades increases
Solution Approach 1:
The patent utilizes thin-walled construction with spar caps and skin panels that form a lightweight yet structurally adequate shell. The shell structure provides aerodynamic surfaces and encloses the core material, creating a lightweight framework that maintains blade integrity while minimizing weight. This allows larger blade dimensions to be achieved without linear increases in weight.
Solution Approach 2:
Core material with porous or cellular structure is employed within the blade interior. These porous materials provide structural support and stiffness while maintaining low density. The porous core reduces overall blade weight compared to solid construction, enabling larger blade sizes for enhanced energy production without proportionally increasing weight and gravitational loads.
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 solution enhances load distribution and reduces stress concentrations while maintaining aerodynamic efficiency, allowing for larger blades without excessive weight, thus addressing the challenge of increased loads and weight.
Implementation Method 1
the reinforcing member extending continuously from the connection point to the anchor end which overlaps a portion of the spar cap so as to transfer load between the spar cap and the respective connecting member
Implementation Method 2
The reinforcing member may include a fibre-reinforced composite material. A majority of the fibres of the fibre-reinforced composite material may be oriented generally towards the blade spanwise direction
Data Source
AI summary
A pitch controlled wind turbine comprising a tower, a nacelle mounted on the tower, a hub mounted rotatably on the nacelle, and at least three wind turbine blades, wherein each wind turbine blade extends between a root end connected to the hub via a pitch mechanism, and a tip end; the wind turbine further comprising at least three blade connecting members, each blade connecting member extending between from a connection point on one wind turbine blade and towards a connection point on a neighbouring wind turbine blade, the connecting points each located at a connection region of a respective blade; and each wind turbine blade comprising a spar cap extending in a blade spanwise outboard direction between the root end and the tip end, and a reinforcing member having an anchor end and a connection end, the connection end having the connection point, the reinforcing member extending continuously from the connection point to the anchor end which overlaps a portion of the spar cap outboard of the connection point so as to transfer load between the spar cap and the respective connecting member.