Wind Turbine Blade Root Joint Using Folded Fiber Rovings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional joints between wind turbine rotor blades and the rotor hub face challenges in distributing loads effectively due to material weakening at the root connection, leading to potential structural integrity issues as blade sizes increase, requiring a cost-effective solution that maintains strength without increasing the connection interface size.
Innovation Solution
A connection joint design featuring integrated, wedge-shaped connecting elements made from composite materials with folded fiber rovings and cross pins that distribute loads without penetrating the blade material, ensuring strong bonding and reduced material removal at the root end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional joints use threaded stud bolts with holes drilled in composite material, then connection is achieved, but material strength is reduced due to fiber damage at hole walls
Solution Approach 1:
The connection joint is divided into multiple discrete connecting elements (e.g., six elements) distributed around the blade root circumference. Each element contains its own bore and connecting features, allowing load distribution across multiple separation points rather than a single continuous connection, thereby reducing stress concentration and preserving composite material strength.
Solution Approach 2:
Metal inserts are embedded within the composite material of the connecting elements. The inserts are positioned in bores that are spaced from the end face, creating a nested structure where the metal insert is contained within the composite element. This nested arrangement allows the harder metal to provide threading and load-bearing capability while the composite material maintains structural integrity and distributes loads.
2Power
If blade size increases to capture more wind energy, then power generation increases, but joint stresses increase requiring larger connection interfaces
Solution Approach 1:
The joint is segmented into multiple discrete connecting elements distributed around the blade root. This segmentation allows the total load from larger blades to be distributed across multiple independent connection points, preventing any single point from experiencing excessive stress that would require an oversized connection interface.
Solution Approach 2:
The bores in the connecting elements are positioned at multiple locations including spacing from the end face and potentially at different radial distances. This multi-dimensional arrangement of connection points allows load distribution in both axial and radial directions, enabling the joint to handle increased loads from larger blades without proportionally increasing the connection interface size.
3Strength
If multiple bores are formed in blade root for T-joint connection, then load distribution improves, but composite material is weakened through extensive hole formation
Solution Approach 1:
The connection is segmented into multiple discrete elements with bores positioned at optimized locations. Rather than forming a continuous pattern of holes through the entire root, the bores are concentrated within specific connecting elements that are strategically positioned, achieving load distribution while minimizing the total volume of composite material affected.
Solution Approach 2:
The connecting elements with embedded metal inserts are positioned at specific locations where loads are most critical. The bores are spaced from the end face and located where they can best distribute loads without compromising the overall structural integrity of the blade root. This localized approach concentrates the necessary holes only where needed rather than throughout the entire root structure.
Data Source
AI summary
A wind turbine rotor blade includes an elongate body having a root end configured to be coupled to a rotor hub of a wind turbine. The rotor blade further includes a connection joint at the root end for connecting the rotor blade to the rotor hub. The connection joint includes a plurality of connecting elements integrated into the root end of the rotor blade and including an eye that defines a bore through the root end of the rotor blade. The connecting elements may be formed from folded fiber rovings wherein the fold forms the eye. A method of making a rotor blade having the connecting element integrated therein, and a method of making the connecting elements are also disclosed.