Wind Turbine Blade Lifting Points and Load Distribution
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Solution Overview
Problem
Conventional handling techniques for large wind turbine blades are problematic due to the lack of a direct fixed connection, leading to potential damage and compromised structural integrity during lifting, especially with dynamically operative structures like trailing edge flaps.
Innovation Solution
A wind turbine blade structure with multiple lifting points and a load-bearing internal structure that includes lift openings and locking elements for secure attachment to lifting members, providing effective load distribution and minimizing stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional slings are used to encircle the blade, then the blade can be lifted, but the blade is susceptible to relative sliding and potential damage to delicate structures
Solution Approach 1:
The blade is divided into multiple lifting points (typically 2-4 points) along its length, each with dedicated lifting lugs or eyes. This segmentation allows the lifting load to be distributed across multiple fixed connection points rather than relying on a single encircling sling, preventing sliding and concentrating stress at designed locations.
Solution Approach 2:
Dedicated lifting lugs, eyes, or brackets are introduced as intermediary components between the blade structure and the lifting sling. These intermediaries provide fixed connection points that transfer lifting forces directly to the blade's load-bearing structure, eliminating the sliding problem associated with direct sling contact and protecting delicate trailing edge structures.
2Ease of operation
If slings are arranged to lift the blade, then lifting can be performed, but damaging forces may be exerted on the trailing edge and blade structure
Solution Approach 1:
Lifting connection points (lugs, eyes, or brackets) are pre-installed on the blade structure during manufacturing, positioned to optimize load distribution. This preliminary action ensures that when lifting occurs, forces are applied at predetermined locations designed to handle such loads, preventing damage to the trailing edge and other delicate structures.
Solution Approach 2:
Dedicated lifting lugs, eyes, or brackets serve as intermediary components that interface between the lifting sling and the blade structure. These intermediaries are strategically positioned away from delicate trailing edge structures and are designed to bear lifting loads, thereby preventing direct contact between slings and vulnerable blade portions.
3Strength
If the blade structure is designed for operating position loading, then it performs well during operation, but it is not optimized for lifting loads constrained at the central region
Solution Approach 1:
The blade structure incorporates locally reinforced lifting points with increased material thickness, stiffening ribs, or integrated lifting lugs/eyes at specific locations. These local quality enhancements provide high load-bearing capacity at lifting points while maintaining the overall blade design optimized for operational aerodynamic loads, allowing the structure to handle both operational and lifting loads effectively.
Data Source
AI summary
A wind turbine blade 2 is formed with structures allowing its lifting by a lifting apparatus 4, the blade comprising upper and lower blade shells and an internal load-bearing structure comprising an internal spar 16 or internal webs, a plurality of lifting points 20 arranged about the blade center of gravity, comprising openings for receiving lifting members 24 of a lifting apparatus insertable therein into structures 22 secured to the load-bearing structure, and with a locking connection being established between the lifting members 24 and the load-bearing structure 16.