Wind Turbine Blade Flange Hybrid Composite T-Bolt Connection
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Solution Overview
Problem
The challenge lies in effectively transferring loads from the fiber composite rotor blades to the metal rotor hub in wind turbines, as conventional designs face difficulties due to the disparate material properties and dynamic load spectra, particularly at the blade root section where loads are concentrated.
Innovation Solution
A T-bolt connection using a hybrid glass fiber/carbon fiber matrix in the flange section of the rotor blade, where carbon fibers are oriented parallel to the blade's longitudinal axis, enhancing stiffness, breaking strength, and bearing strength, allowing for closer spacing of bores and increased number of T-bolt connections, thereby improving static and fatigue strength and reducing material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional monocoque type rotor blade with glass fiber reinforced plastic is used, then the blade structure is simple and easy to manufacture, but the load transfer from the fiber composite structure to the metal rotor hub is difficult due to substantially different material properties
Solution Approach 1:
The patent applies composite materials by using a hybrid fiber reinforcement structure in the flange section, combining glass fibers and carbon fibers in a matrix material. This composite approach enables effective load transfer from the fiber composite blade structure to the metal rotor hub by creating a transition zone with optimized material properties that bridge the gap between dissimilar materials.
Solution Approach 2:
The patent implements local quality by providing a flange section at the blade root with hybrid fiber reinforcement (glass and carbon fibers) while the rest of the blade uses conventional glass fiber reinforcement. This localized enhancement of material properties at the critical connection zone improves load transfer strength without unnecessarily increasing complexity throughout the entire blade structure.
2Strength
If the root section of the rotor blade is made with conventional glass fiber reinforced plastic, then the material usage is high and weight is increased, but the joint stiffness and strength of the T-bolt connection is insufficient
Solution Approach 1:
The patent uses hybrid fiber composite materials in the flange section, combining glass fibers and carbon fibers. Carbon fibers provide high stiffness and strength-to-weight ratio, enabling reduced material usage while maintaining or improving joint stiffness and strength of the T-bolt connection compared to conventional glass fiber reinforced plastic.
Solution Approach 2:
The patent changes the material parameters in the flange section by introducing carbon fibers with different mechanical properties (higher modulus and strength) compared to conventional glass fiber reinforced plastic. This parameter change allows for optimized structural design with reduced weight while achieving the required joint stiffness and strength.
3Strength
If glass fiber reinforced plastic is used in the root section, then material usage is high, but the breaking strength and bearing strength are insufficient for optimal T-bolt connection design
Solution Approach 1:
The patent employs hybrid fiber composite materials combining glass and carbon fibers in the flange section. Carbon fibers contribute superior breaking strength and bearing strength properties, allowing the T-bolt connection to be designed with optimal performance while reducing the total quantity of material required compared to conventional glass fiber reinforced plastic.
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 configuration enhances the joint stiffness and strength of the T-bolt connection, reduces dynamic loads, and allows for a lighter and cheaper rotor blade and hub design by minimizing material usage while improving fatigue resistance and load distribution.
Implementation Method 1
The joint portion is fabricated from a hybrid material including glass fibers and carbon fibers embedded in a matrix material
Implementation Method 2
the carbon fibers are oriented substantially parallel to the longitudinal axis of the rotor blade
Data Source
Figure 1~2
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Figure 5~6
AI summary
A rotor blade (140) for a wind turbine (100) includes a flange section configured to connect the rotor blade to a rotor hub (130). The flange section is formed from a hybrid material including glass fibers (10) and carbon fibers (15) embedded in a matrix material (20). The carbon fibers are oriented substantially parallel to a longitudinal axis of the rotor blade.