Segmented Wind Turbine Blade Joint With Axial Preload Tabs
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Solution Overview
Problem
Segmented rotor blades for wind turbines face challenges in transport due to increasing length, requiring precise manufacturing and assembly, which increases production costs and reduces productivity, while existing connection methods like bolted spars and longitudinal bolting limit load-bearing capacity and aerodynamic efficiency.
Innovation Solution
A segmented rotor blade design using transverse bolts with axial preloading elements to connect spar elements, eliminating the need for longitudinal bolting and allowing for mass production, with connecting tabs and shear connection elements to enhance stability and reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If rotor blade length is increased to generate more energy, then power generation efficiency is improved, but transportability deteriorates
Solution Approach 1:
The rotor blade is divided into multiple blade segments that can be transported separately and assembled at the installation site. This segmentation allows longer rotor blades to be broken down into transportable sections while maintaining the overall length needed for high power generation efficiency.
2Length of moving object
If segmented rotor blades are used to improve transportability, then transportability is improved, but manufacturing precision requirements worsen
Solution Approach 1:
A connecting assembly acts as an intermediary component between blade segments, incorporating bushings that receive transverse bolts. This intermediary structure simplifies the connection process and reduces the precision requirements for direct blade segment interfaces, as the bushings accommodate alignment tolerances.
Solution Approach 2:
The connection design allows for parameter variations in positioning through the use of bushings with specific tolerances and transverse bolts that can accommodate manufacturing variations. This enables assembly despite normal manufacturing precision limitations.
3Reliability
If bushings are positioned with high precision to ensure perfect axial alignment, then connection quality is improved, but production complexity worsens
Solution Approach 1:
The bushing serves as a mediator that absorbs positioning tolerances and simplifies the alignment process. Instead of requiring precise positioning of connecting elements directly between blade segments, the bushings provide a tolerance-absorbing interface that maintains connection quality while reducing production complexity.
4Manufacturing precision
If additional processing steps are added to create bushing bores, then connection precision is improved, but productivity worsens
Solution Approach 1:
The bushings are pre-positioned and fixed in the blade segments during the lamination process before final assembly. This preliminary action ensures that the bushings are already in their correct positions when segments are brought together, eliminating the need for additional on-site processing steps and maintaining both precision and productivity.
5Ease of operation
If insert bolts are used to connect blade segments, then ease of assembly is improved, but load-bearing capacity worsens
Solution Approach 1:
The connection design uses transverse bolts that can accommodate dynamic loads and movements in the blade segments. The bushings allow for slight movements and adjustments while maintaining a secure connection, providing both ease of assembly and adequate load-bearing capacity under varying operational conditions.
Data Source
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AI summary
The invention relates to a segmented rotor blade for wind turbines with at least two blade segments, wherein each blade segment has at least one inner spar element, wherein the first spar element and the second spar element are joined together at the joint with their end faces by means of a connecting arrangement, wherein the connecting arrangement has a plurality of connecting assemblies, each of which connects the spar elements together, wherein each connecting assembly comprises a first transverse bolt, a second transverse bolt and at least one connecting tab, which has a first tab opening and a second tab opening at its ends.and wherein, in each connecting assembly, the first transverse bolt is guided transversely to the longitudinal direction of the rotor blade through a spar opening in the first spar element and the first tab opening of the connecting tab, and the second transverse bolt is guided transversely to the longitudinal direction of the rotor blade through a spar opening in the second spar element and the second tab opening of the connecting tab, so that the connecting tab connects the spar elements to one another. According to the invention, at least one of the transverse bolts of a connecting assembly is designed as an axial preloading element, which, in the installed state, exerts a rotor blade-related axial preload on the at least one connecting tab of the connecting assembly such that the end faces of the spar elements are pressed together.