Jointed Wind Turbine Blade Offset Compensation
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Solution Overview
Problem
Jointed wind turbine rotor blades experience increased vibration and noise due to flap-wise and twist-wise offsets at the joint line, which reduce power performance and generate turbulent vortices, especially with chord-wise bolt or pin configurations that transfer loads from the chord-wise bolt into the blade shells.
Innovation Solution
A method to determine and compensate for induced flap-wise, twist-wise, or yawl-wise offsets by modifying the joint structure's configuration, including altering the location of a chord-wise pin or adding/removing materials to achieve counter offsets, thereby reducing noise and vibration at the joint line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a chord-wise bolt or pin is used to transfer loads from the chord-wise bolt into the blade shells, then load transfer capability is improved, but flap-wise and twist-wise offsets at the joint line increase causing increased vibration and noise
Solution Approach 1:
The joint structure is pre-configured with specific geometric parameters (pin location, spar cap orientation, material distribution) during manufacturing to anticipate and compensate for load-induced deformations. This preliminary configuration ensures that when loads are applied, the offsets at the joint line are minimized, thereby reducing vibration and noise while maintaining load transfer capability.
Solution Approach 2:
The invention modifies key geometric parameters of the joint structure, including the chord-wise pin location, spar cap orientation angles, and material distribution. By optimizing these parameters, the structure achieves better load distribution and reduced offsets at the joint line, effectively lowering vibration and noise without compromising strength.
2Reliability
If blade segments are joined together with a beam structure and multiple bolt joints, then structural connection is improved, but relative deflections result in flap-wise offsets between shell members at the joint line
Solution Approach 1:
The invention applies local quality by concentrating structural reinforcement and specific geometric configurations at the joint line area. The spar caps are oriented at specific angles and the chord-wise pin is positioned at a optimized location to locally manage stresses and deformations, ensuring that the joint maintains structural integrity while minimizing flap-wise offsets.
3Force
If the joint structure uses a span-wise spaced chord-wise bolt, then load transfer into blade shells is improved, but combination with stiffness difference results in flap-wise offsets between shell members
Solution Approach 1:
The spar caps act as intermediary elements between the chord-wise pin and the blade shells. By orienting the spar caps at specific angles and positioning them strategically, they mediate the load transfer process, distributing forces more evenly and reducing the flap-wise offsets that would otherwise occur due to the span-wise spacing of the chord-wise bolt.
Data Source
Figure 1
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AI summary
A method to reduce noise and vibration between separate blade segments (30, 32) of a jointed wind turbine rotor blade (28) includes determining an actual offset (68) at a chord-wise joint line (34) between the shell members (31,33) of the first (30) and second (32) blade segments at a load condition on the jointed wind turbine rotor blade, wherein the offset (68) is any one or combination of a flap-wise offset (70), a twist-wise offset (72), or a yawl-wise offset (77). The method defines a modified configuration (74) of the joint structure (36) at a no-load condition on the wind turbine rotor blade (28) that compensates at least partially for the actual offset (68) at the load condition, and the first (30) and second (32) blade segments are connected with the modified configuration (74) of the joint structure (36).