Wind Turbine Blade Root Reinforcing Ring Stress Distribution
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Solution Overview
Problem
Existing wind turbine blade roots experience unbalanced load distribution and potential structural damage due to severe loads, as stress is concentrated through longitudinal reinforcing elements interacting only via annular shell material, leading to potential damage even with minor defects.
Innovation Solution
A wind turbine blade root design featuring an annular structure with first and second longitudinal reinforcing elements connected by a reinforcing ring with threaded holes, allowing for improved stress distribution and load transmission through the ring, rather than solely through the longitudinal elements, and enabling connection to the hub via screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If longitudinal reinforcing elements interact only via annular shell material, then the blade root structure is simpler, but stress distribution becomes unbalanced and force concentrations occur leading to structural damage
Solution Approach 1:
A reinforcing ring is introduced as an intermediary element between the longitudinal reinforcing elements. This ring acts as a mediator that distributes loads evenly among the longitudinal elements, preventing force concentrations and stress imbalances that would otherwise occur through the annular shell material alone.
Solution Approach 2:
The solution transitions from a two-dimensional interaction through the annular shell to a three-dimensional load distribution system by adding the reinforcing ring. This creates an additional structural dimension that enables more effective stress distribution across multiple loading paths.
2Device complexity
If threaded bushings serve as both longitudinal reinforcing elements and fastening elements, then the number of components is reduced, but load distribution becomes severely unbalanced
Solution Approach 1:
The solution separates the functions of longitudinal reinforcement and fastening into distinct components. The longitudinal reinforcing elements focus on load transmission, while the reinforcing ring with threaded holes handles the fastening function. This segmentation allows each component to be optimized for its specific function, resulting in balanced load distribution.
Solution Approach 2:
The reinforcing ring serves as an intermediary that decouples the fastening function from the longitudinal reinforcing elements. By providing separate threaded holes in the ring, the fastening load is distributed independently from the longitudinal load paths, preventing the severe unbalance that occurs when both functions are combined in single bushings.
3Device complexity
If longitudinal reinforcing elements transmit stress through annular shell material only, then the structure is simpler, but force concentrations occur even with microscopic defects
Solution Approach 1:
The reinforcing ring acts as a protective intermediary that distributes forces evenly across all longitudinal reinforcing elements. This prevents force concentrations that would otherwise concentrate on specific points in the annular shell material, where microscopic defects could initiate damage or propagation.
Solution Approach 2:
The reinforcing ring provides preemptive load distribution that cushions against potential force concentrations before they can cause damage. By distributing loads evenly across multiple elements through the ring, the system prevents the buildup of critical stress concentrations that could exploit microscopic defects.
Data Source
AI summary
A wind turbine blade root having: an annular structure extending about a main axis and made of a composite material including a matrix and reinforcing fibers; first longitudinal reinforcing elements, which are incorporated in the annular structure, extend in the direction of the main axis, and are spaced apart in a circle about the main axis; and an annular reinforcing element connecting the first longitudinal reinforcing elements and having first coupling portions for connection to the first longitudinal reinforcing elements.