Segmented Wind Turbine Blade Root End Joint
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Solution Overview
Problem
The high thickness of root end joints in wind turbine blades generates excessive heat during resin curing and drilling, leading to material damage and increased manufacturing costs, with existing methods requiring large and expensive jigs for accurate drilling.
Innovation Solution
Breaking down the root end into smaller segments with a higher concentration of uni-axial fibers for stiffness and multi-axial fibers for torsional strength, allowing for reduced heat generation and simplified drilling, and forming connection holes within the segments or using disposable inserts for improved handling and bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the root end joint is made with high thickness (50mm-150mm) to meet structural requirements, then the load-bearing capability is improved, but excessive heat is generated during resin curing causing material damage
Solution Approach 1:
The root end joint is divided into multiple segments (typically 4 segments) that are assembled together. This segmentation reduces the uncured resin mass in each segment, thereby reducing exothermic heat generation during curing while maintaining the overall structural strength through proper segment design and assembly. Each segment can be cured independently with controlled heat generation, avoiding the heat damage that would occur in a single thick component.
2Manufacturing precision
If large jigs are used for accurate drilling of connection holes in the thick root end, then drilling precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
By dividing the root end into smaller segments, the drilling operation is performed on much smaller, more manageable pieces rather than a single thick component. This allows for the use of smaller, simpler, and more accurate drilling jigs for each segment, reducing overall device complexity and manufacturing cost while maintaining high drilling precision.
Solution Approach 2:
Connection holes are drilled in the root segments before assembly, when the segments are still small and accessible. This preliminary action allows for easier and more accurate drilling operations compared to drilling through the assembled thick root end, simplifying the jig requirements and improving manufacturing efficiency.
3Stability of the object's composition
If the root end is drilled and assembled as a single large component, then structural integrity is maintained, but handling and drilling become difficult and time-consuming
Solution Approach 1:
The root end is segmented into smaller, more manageable pieces that are easier to handle, transport, and process individually. Each segment can be independently manufactured, drilled, and prepared, significantly improving ease of operation. The segments are then assembled with bonding agents or mechanical fasteners to restore the structural integrity of the complete root end, achieving both improved operability and maintained structural strength.
4Object-affected harmful factors
If drilling holes in the thick root end is performed with careful heat control, then material damage is prevented, but manufacturing time and cost increase
Solution Approach 1:
Segmenting the root end reduces the amount of material that needs to be drilled through, decreasing drilling time and heat generation. The smaller segments require less precise heat control during drilling, allowing for faster, more efficient manufacturing while still preventing material damage. This approach significantly improves productivity compared to drilling a single thick component.
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
This method reduces heat-related damage, simplifies drilling and handling, and enhances the structural integrity of the root end joint with a strong bond, reducing waste and assembly complexity while maintaining high load-bearing capabilities.
Implementation Method 1
When the resin system is curing, it generates heat in an exothermic reaction. In the thick areas of the root, the heat generated can become so much that it causes damage with the finished component
Data Source
Figure 1A~1C
Figure 2~3A
Figure 3B~3C
AI summary
A method of making a root end joint for a wind turbine. A plurality of root segments (10) are formed of a composite material. Each has an arcuate end face (11) which subtends an angle of 90° or less and has a plurality of connection holes (12). The segments are joined together side- by-side to build up the circular profile of the root end. The segments include a proportion of uni-axial to multiaxial fiber which decreases from the arcuate end face towards the opposite end.